Document:

<PAGE>   1

                                                                    EXHIBIT 10.5

                                  OFFICE LEASE

                                     between

 OTR, AN OHIO GENERAL PARTNERSHIP, AS NOMINEE OF THE STATE TEACHERS RETIREMENT
      BOARD OF OHIO, A STATUTORY ORGANIZATION CREATED BY THE LAWS OF OHIO

                                   (Landlord)

                                      and

                               CHEMCONNECT, INC.

                             a Delaware Corporation

                                    (Tenant)

                                  for Premises

                              44 Montgomery Street
                           San Francisco, California

<PAGE>   2

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
<S>                                                                                               <C>
ARTICLE I - SUMMARY AND CERTAIN DEFINITIONS.................................................       1
        1.1  Building.......................................................................       1
        1.2  Premises.......................................................................       1
        1.3  Rentable Area of the Premises..................................................       1
        1.4  Lease Year.....................................................................       1
        1.5  Lease Term.....................................................................       1
        1.6  Commencement Date..............................................................       1
        1.7  Expiration Date................................................................       1
        1.8  Base Rent......................................................................       1
        1.9  Tenant's Percentage Share......................................................       1
        1.10  Security Deposit..............................................................       1
        1.11  Tenant's Permitted Use........................................................       1
        1.12  Business Hours................................................................       1
        1.13  Landlord's Address For Notices................................................       1
        1.14  Tenant's Address For Notices..................................................       2
        1.15  Brokers.......................................................................       2
        1.16  Guarantors....................................................................       2

ARTICLE II - PREMISES.......................................................................       2
        2.1  Lease of Premises..............................................................       2
        2.2  Acceptance of Premises.........................................................       2

ARTICLE III - PREMISES......................................................................       2
        3.1  Term...........................................................................       2

ARTICLE IV - RENTAL.........................................................................       2
        4.1  Definitions....................................................................       2
             4.1.1  Base Year...............................................................       2
             4.1.2  Property Taxes..........................................................       2
             4.1.3  Operating Expenses......................................................       4
             4.1.4  Exclusions from Operating Expenses......................................       4
             4.1.5  Adjustment..............................................................       4
        4.2  Base Rent......................................................................       4
             4.2.1  Rent Adjustment.........................................................       4
             4.2.2  Tax and Operating Expense Adjustment....................................       4
             4.2.3  Tax Exempt Tenant.......................................................       4
        4.3  Adjustment Procedure; Estimates................................................       5
             4.3.1  Estimates...............................................................       5
             4.3.2  Landlord's Statement....................................................       5
             4.3.3  Termination.............................................................       5
        4.4  Review of Landlord's Statement.................................................       5
             4.4.1  Notice..................................................................       6
             4.4.2  Records.................................................................       6
             4.4.3  Landlord's Review; Reconciliation.......................................       6
        4.5  Payment........................................................................       6
        4.6  Late Charge; Interest..........................................................       6
        4.7  Additional Rent................................................................       7
        4.8  Additional Taxes...............................................................       7

ARTICLE V - SECURITY DEPOSIT................................................................       7

ARTICLE VI - USE OF PREMISES................................................................       7
        6.1  Tenant's Permitted Use.........................................................       7
        6.2  Compliance With Laws and Other Requirements....................................       7
             6.2.1  Applicable Law..........................................................       7
             6.2.2  No Violation............................................................       7
        6.3  Hazardous Materials............................................................       8
             6.3.1  Prohibition.............................................................       8
             6.3.2  Remediation.............................................................       8
             6.3.3  Additional Documents....................................................       8
</TABLE>

                                       i
<PAGE>   3
<TABLE>
<CAPTION>
<S>                                                                                               <C>
             6.3.4  Environmental Laws......................................................       8
             6.3.5  Hazardous Materials.....................................................       8
             6.3.6  Handle..................................................................       8
             6.3.7  Regulatory Authority....................................................       8

ARTICLE VII - UTILITIES AND SERVICES........................................................       9
        7.1  Building Services..............................................................       9
             7.1.1  Elevator Service........................................................       9
             7.1.2  HVAC....................................................................       9
             7.1.3  Water...................................................................       9
             7.1.4  Janitorial and Cleaning.................................................       9
             7.1.5  Electricity.............................................................       9
             7.1.6  Payments................................................................       9
        7.2  Interruption of Service........................................................      10
        7.3  Utility Deregulation...........................................................      10

ARTICLE VIII - MAINTENANCE AND REPAIRS......................................................      10
        8.1  Landlord's Obligations.........................................................      10
        8.2  Tenant's Obligations...........................................................      10
        8.3  Landlord's Rights..............................................................      11

ARTICLE IX - ALTERATIONS, ADDITIONS AND IMPROVEMENTS........................................      11
        9.1  Landlord's Consent; Conditions.................................................      11
        9.2  Performance of Alterations Work................................................      11
        9.3  Liens..........................................................................      11
        9.4  Lease Termination..............................................................      12

ARTICLE X - INDEMNIFICATION AND INSURANCE...................................................      12
        10.1  Indemnification...............................................................      12
             10.1.1  Tenant.................................................................      12
             10.1.2  Landlord...............................................................      13
             10.1.3  No Limitation..........................................................      13
        10.2  Property Insurance............................................................      13
             10.2.1  Tenant All-Risk........................................................      13
             10.2.2  Tenant Business Interruption...........................................      13
             10.2.3  Landlord All-Risk......................................................      13
        10.3  Liability Insurance...........................................................      13
             10.3.1  Tenant.................................................................      13
             10.3.2  Alcohol................................................................      13
             10.3.3  Estimates..............................................................      14
        10.4  Workers' Compensation Insurance...............................................      14
        10.5  Policy Requirements...........................................................      14
        10.6  Waiver of Subrogation.........................................................      14
        10.7  Failure to Insure.............................................................      14

ARTICLE XI - DAMAGE OR DESTRUCTION..........................................................      14
        11.1  Total Destruction.............................................................      14
        11.2  Partial Destruction of Premises...............................................      14
        11.3  Exceptions to Landlord's Obligations..........................................      15
        11.4  Waiver........................................................................      15

ARTICLE XII - CONDEMNATION..................................................................      15
        12.1  Taking........................................................................      15
        12.2  Award.........................................................................      15
        12.3  Temporary Taking..............................................................      15

ARTICLE XIII - RELOCATION...................................................................      15

ARTICLE XIV - ASSIGNMENT AND SUBLETTING.....................................................      15
        14.1  Restriction...................................................................      15
        14.2  Notice to Landlord............................................................      16
             14.2.1  Statement..............................................................      16
             14.2.2  Original Documents.....................................................      16
</TABLE>

<PAGE>   4

<TABLE>
<CAPTION>
<S>                                                                                              <C>
        14.3  Landlord's Recapture Rights...................................................      16
        14.4  Landlord's Consent; Standards.................................................      16
        14.5  Additional Rent...............................................................      17
        14.6  Landlord's Costs..............................................................      17
        14.7  Continuing Liability of Tenant................................................      17
        14.8  Non-Waiver....................................................................      17

ARTICLE XV - DEFAULT AND REMEDIES...........................................................      17
        15.1  Events of Default By Tenant...................................................      17
             15.1.1  Failure to Pay Rent....................................................      17
             15.1.2  Abandonment............................................................      17
             15.1.3  Failure to Perform.....................................................      18
             15.1.4  Bankruptcy.............................................................      18
             15.1.5  Misstatement...........................................................      18
        15.2  Landlord's Right To Terminate Upon Tenant Default.............................      18
        15.3  Mitigation of Damages.........................................................      18
        15.4  Landlord's Right to Continue Lease Upon Tenant Default........................      19
        15.5  Right of Landlord to Perform..................................................      19
        15.6  Default Under Other Leases....................................................      19
        15.7  Non-Waiver....................................................................      19
        15.8  Cumulative Remedies...........................................................      19
        15.9  Default by Landlord...........................................................      20

ARTICLE XVI - ATTORNEYS' FEES; INDEMNIFICATION..............................................      20
        16.1  Attorneys' Fees...............................................................      20
        16.2  Indemnification...............................................................      20

ARTICLE XVII - SUBORDINATION AND ATTORNMENT.................................................      20
        17.1  Subordination.................................................................      20
        17.2  Attornment....................................................................      21
        17.3  Mortgagee Protection..........................................................      21

ARTICLE XVIII - MISCELLANEOUS...............................................................      21
        18.1  Quiet Enjoyment...............................................................      21
        18.2  Rules and Regulations.........................................................      21
        18.3  Estoppel Certificates.........................................................      22
        18.4  Entry by Landlord.............................................................      22
        18.5  Landlord's Lease Undertakings.................................................      22
        18.6  Transfer of Landlord's Interest...............................................      23
        18.7  Holdover......................................................................      23
        18.8  Notices.......................................................................      23
        18.9  Brokers.......................................................................      23
        18.10  Communications and Computer Lines............................................      24
             18.10.1  New Lines.............................................................      24
             18.10.2  Line Problems.........................................................      24
        18.11  Entire Agreement.............................................................      24
        18.12  Amendments...................................................................      24
        18.13  Successors...................................................................      24
        18.14  Force Majeure................................................................      24
        18.15  Survival of Obligations......................................................      24
        18.16  Light and Air................................................................      25
        18.17  Governing Law................................................................      25
        18.18  Severability.................................................................      25
        18.19  Captions.....................................................................      25
        18.20  Interpretation...............................................................      25
        18.21  Independent Covenants........................................................      25
        18.22  Number and Gender............................................................      25
        18.23  Time is of the Essence.......................................................      25
        18.24  Joint and Several Liability..................................................      25
        18.25  Exhibits.....................................................................      25
        18.26  Offer to Lease...............................................................      25
        18.27  No Counterclaim; Choice of Laws..............................................      25
        18.28  Rights Reserved by Landlord..................................................      25
</TABLE>
<PAGE>   5

<TABLE>
<CAPTION>
<S>                                                                                               <C>
        18.29  Asbestos.....................................................................      26
        18.30  ADR Process..................................................................      26
        18.31  Miscellaneous Signage........................................................      27
</TABLE>

                                    EXHIBITS

<TABLE>
<CAPTION>
<S>              <C>
Exhibit A        Floor Plan of Premises
Exhibit B        Work Letter Agreement
Exhibit C        Rules and Regulations
Exhibit D        None
Exhibit E        Acceptance Letter
</TABLE>

<PAGE>   6

                                  OFFICE LEASE

        THIS OFFICE LEASE ("Lease"), dated September 20, 1999, is made and
entered into by and between OTR, AN OHIO GENERAL PARTNERSHIP, as Nominee of The
State Teachers Retirement Board of Ohio, a statutory organization created by the
laws of Ohio ("Landlord"), and CHEMCONNECT, INC. a Delaware corporation
("Tenant") upon the following terms and conditions:

        ARTICLE I - SUMMARY AND CERTAIN DEFINITIONS

        Unless the context otherwise specifies or requires, the following terms
shall have the meanings specified herein:

        1.1 BUILDING. The term "Building" shall mean that certain office
building located at 44 Montgomery Street in San Francisco, California, commonly
known as 44 MONTGOMERY STREET together with any related land, improvements,
common areas, driveways, sidewalks and landscaping.

        1.2 PREMISES. The term "Premises" shall mean Suite 280 in the Building,
as more particularly outlined on the "Floor Plan" attached hereto as Exhibit "A"
and incorporated herein by reference. As used herein, "Promises" shall not
include any storage area in the Building or rooftop area on the Building, which
areas shall (if applicable) be leased or rented pursuant to separate written
agreements.

        1.3 RENTABLE AREA OF THE PREMISES. The term "Rentable Area of the
Premises" shall mean One Thousand Three Hundred and Twenty Eight (1,328) square
feet, which Landlord and Tenant have stipulated as the Rentable Area of the
Premises.

        1.4 LEASE YEAR. The term "Lease Year" shall mean such consecutive twelve
(12) month period following the Commencement Date.

        1.5 LEASE TERM. The term of this Lease ("Lease Term") shall be for a
period of two consecutive Lease Years one month and seventeen days following the
Commencement Date, unless sooner terminated as otherwise provided in this Lease.

        1.6 COMMENCEMENT DATE. Subject to adjustment as provided in Section 3.1,
the term "Commencement Date" shall mean the sooner of October 15, 1999, or upon
occupancy of the Premises.

        1.7 EXPIRATION DATE. Subject to adjustment as provided in Section 3.1,
the term "Expiration Date" shall mean December 31, 2001.

        1.8 BASE RENT. Subject to adjustment as provided in Article 4, the term
"Base Rent" shall mean the following amounts for the following periods:

<TABLE>
<CAPTION>
Period                Monthly Base Rent      Annual Rate/RSF       Annual Base Rent
------                -----------------      ---------------       ----------------
<S>                      <C>                    <C>                   <C>
10/15/99-11/30/00        $3,873.33              $35.00                $46,480.00
12/01/00-12/31/01        $4,094.67              $37.00                $49,136.00
</TABLE>

        1.9 TENANT'S PERCENTAGE SHARE. Subject to adjustment by Acceptance
letter, the term "Tenant's Percentage Share" shall mean 0.21% with respect to
increases in Property Taxes and Operating Expenses (as such terms are
hereinafter defined). Landlord may reasonably recompute Tenant's Percentage
Share from time to time to reflect reconfigurations, additions or modifications
to the Premises or Building.

        1.10 SECURITY DEPOSIT. The term "Security Deposit" shall mean $5,000
delivered by Tenant to Landlord to secure Tenant's performance of its
obligations hereunder.

        1.11 TENANT'S PERMITTED USE. The term "Tenant's Permitted Use" shall
mean general and administrative office use, and no other use.

        1.12 BUSINESS HOURS. The term "Business Hours" shall mean the hours of
8:00 A.M. to 6:00 P.M., Monday through Friday, and 9:00 A.M. to 1:00 P.M.,
Saturdays (federal and state holidays excepted). "Holidays" are defined to be
the following days: New Years Day,

                                       1
<PAGE>   7

Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day,
and to the extent of utilities or services provided by union members engaged at
the Building, such other holidays observed by such unions.

        1.13 LANDLORD'S ADDRESS FOR NOTICES. The term "Landlord's Address for
Notices" shall mean OTR c/o Seagate Properties, Inc., 44 Montgomery Street,
Suite 1710, San Francisco, California 94104, Attn: Property Manager, with a copy
(but which copy shall not constitute notice) to OTR, 275 Broad Street, Columbus,
Ohio, Attn: Director, Real Estate.

        1.14 TENANT'S ADDRESS FOR NOTICES. The term "Tenant's Address for
Notices" shall mean 44 Montgomery Street, Suite 250, San Francisco, CA 94104.

        1.15 BROKERS. The term "Brokers" shall mean Seagate Properties, Inc.

        1.16 GUARANTORS. The term "Guarantors" shall not be applicable to this
Lease.

                            ARTICLE II --- PREMISES

        2.1 LEASE OF PREMISES. Commencing on the Commencement Date, Landlord
agrees to and shall lease the Premises to Tenant, and Tenant agrees to and shall
lease and hire the Premises from Landlord, upon all of the terms, covenants and
conditions contained in this Lease.

        2.2 ACCEPTANCE OF PREMISES. Unless otherwise specifically set forth in
this Lease, Tenant acknowledges that Landlord has not made any representation or
warranty with respect to the condition of the Premises or the Building or with
respect to the suitability or fitness of either for the conduct of Tenant's
Permitted Use or for any other purpose. Prior to Tenant's taking possession of
the Premises, Landlord or its designee and Tenant will walk the Premises for the
purpose of reviewing the condition of the Premises. Within ten (10) business
days after such review, Landlord and Tenant shall execute and deliver to each
other duplicate original counterparts of the Acceptance Letter. Except as is
expressly set forth in this Lease or Work Letter Agreement, or as may be
expressly set forth in the Acceptance Letter, Tenant agrees to accept the
Premises in its "as is" physical condition without any agreements,
representations, understandings or obligations on the part of Landlord to
perform any alterations, repairs or improvements (or to provide any allowance
for same). Notwithstanding the foregoing, Landlord represents that as of the
Commencement Date, all Building operating systems pertinent to the Premises are
in good working repair.

                            ARTICLE III --- PREMISES

        3.1 TERM. Except as otherwise provided in this Lease, the Lease Term
shall be for the period described in Section l.5 of this Lease, commencing on
the Commencement Date described in Section 1.6 of this Lease and ending on the
Expiration Date described in Section 1.7 of this Lease; provided, however, that,
for any reason, Landlord is unable to deliver possession of the Premises on the
date described in Section 1.6 of this Lease, Landlord shall not be liable for
any damage caused thereby, nor shall the Lease be void or voidable, but, rather,
the Lease Term shall commence upon, and the Commencement Date shall be the date
that possession of the Premises is so tendered to Tenant (except for
Tenant-caused delays which shall not be deemed to delay commencement of the
Lease Term), and, unless Landlord elects otherwise, the Expiration Date
described in Section 1.7 of this Lease shall be extended by an equal number of
days.

                             ARTICLE IV --- RENTAL

        4.1 DEFINITIONS. Unless the context otherwise specifies or requires, the
following terms shall have the meanings specified herein:

             4.1.1. Base Year. The term "Base Year" shall mean calendar year
2000.

             4.1.2. Property Taxes. The term "Property Taxes" shall mean the
aggregate amount of all real estate taxes, assessments (whether they be general
or special), sewer rents and charges, transit taxes, taxes based upon the
receipt of rent and any other federal, state or local governmental charge,
general, special, ordinary or extraordinary (but not including income or
franchise taxes, capital stock, inheritance, estate, gift, or any other taxes
imposed upon or measured by Landlord's gross income or profits, unless the same
shall be imposed in lieu of real estate taxes or other ad valorem taxes), which
Landlord shall pay or become obligated to pay

<PAGE>   8

in connection with the Building, or any part thereof. Property Taxes shall also
include all fees and costs, including attorneys' fees, appraisals and
consultants' fees, incurred by Landlord in seeking to obtain a reassessment,
reduction of, or a limit on the increase in, any Property Taxes, but the total
of said fees and costs shall not exceed the amount of any reduction in Property
Taxes actually granted. If due to Landlord's gross negligence it fails to timely
pay any installment of Property Taxes, and as a direct consequence thereof the
taxing authority assesses a late fee or penalty, said late fee or penalty shall
not be included in Property Taxes. Property Taxes for any calendar year shall be
Property Taxes which are due for payment or paid in such year, rather than
Property Taxes which are assessed or become a lien during such year. Property
Taxes shall include any tax, assessment, levy, imposition or charge imposed upon
Landlord and measured by or based in whole or in part upon the Building or the
rents or other income from the Building, to the extent that such items would be
payable if the Building was the only property of Landlord subject to same and
the income received by Landlord from the Building was the only income of
Landlord. Property Taxes shall also include any personal property taxes imposed
upon the furniture, fixtures, machinery, equipment, apparatus, systems and
appurtenances of Landlord used in connection with the Building.

             4.1.3. Operating Expenses. The term "Operating Expenses" shall mean
all costs, fees, disbursements and expenses paid or incurred by or on behalf of
Landlord in the operation, ownership, maintenance, insurance, management,
replacement and repair of the Building (excluding Property Taxes) including
without limitation:

                  (i) Premiums for property, casualty, liability, earthquake,
Rent interruption or other types of insurance carried by Landlord to the extent
carried by other institutional owners and operators of first class office.

                  (ii) Salaries, wages, and other amounts paid or payable for
personnel including the Building manager, superintendent, operation and
maintenance staff, and other employees of Landlord involved in the maintenance
and operation of the Building, including contributions and premiums towards
fringe benefits, unemployment, disability and worker's compensation insurance,
pension plan contributions and similar premiums and contributions and the total
charges of any independent contractors or property managers engaged in the
operation, repair, care, maintenance and cleaning of any portion of the
Building.

                  (iii) Cleaning expenses, including without limitation
janitorial services, window cleaning, and garbage and refuse plants.

                  (iv) Landscape expenses, including without limitation
irrigation, trimming, mowing, fertilizing, seeding, and replacing plants.

                  (v) Heating, ventilating, air conditioning and steam/utilities
expenses, including fuel, gas, electricity, water, sewer, telephone, and other
services.

                  (vi) Maintaining operating, repairing and replacing components
of equipment or machinery, including without limitation heating, refrigeration,
ventilation, electrical, plumbing, mechanical, elevator, escalator, sprinklers,
fire/life safety, security and energy management system, including service
contractors, maintenance contracts, supplies and parts.

                  (vii) Other items of repair or maintenance of elements of the
Building.

                  (viii) The costs of policing, security and supervision of the
Building.

                  (ix) Fair market rental and other costs with respect to the
management office for the Building.

                  (x) The cost of the rental of any machinery or equipment and
the cost of supplies used in the maintenance and operation of the Building.

                  (xi) Audit fees and the cost of accounting services incurred
in the preparation of statements referred to in this Lease and financial
statements, and in the computation of the rents and charges payable by tenants
of the Building.

<PAGE>   9

                  (xii) Capital expenditures (a) made primarily to reduce
Operating Expenses or to comply with any laws or other governmental requirements
applicable to the Building, or (b) for replacements (as opposed to additions or
new improvements) of items located in the common areas of the Building, required
to keep such areas in good condition; provided all such permitted capital
expenditures (together with reasonable financing charges) shall be amortized for
purposes of this Lease over the shorter of (x) their useful lives, (y) the
period during which the reasonably estimated savings in Operating Expenses
equals the expenditures, or (z) three (3) years.

                  (xiii) Legal fees and expenses.

                  (xiv) Payments under any easement, operating agreement,
declaration, restrictive covenant, or instrument pertaining to the sharing of
costs in any planned development.

                  (xv) A fee for the administration and management of the
Building as reasonably determined by Landlord from time to time.

             4.1.4. Exclusions from Operating Expenses. Operating Expenses shall
not include costs of alteration of the premises of tenants of the Building,
depreciation charges, interest and principal payments on mortgages, ground
rental payments, real estate brokerage and leasing commissions, expenses
incurred in enforcing obligations of tenants of the Building, salaries and other
compensation of executive officers of the managing agent of the Building senior
to the Building manager, costs of any special service provided to any one tenant
of the Building but not to tenants of the Building generally, and costs of
marketing or advertising the Building.

             4.1.5. Adjustment. If the Building does not have one hundred
percent (100%) occupancy during an entire calendar year, including the Base
Year, then the variable cost component of "Property Tax" and "Operating
Expenses" shall be equitably adjusted so that the total amount of Property Tax
and Operating Expenses equals the total amount which would have been paid or
incurred by Landlord had the Building been one hundred percent (100%) occupied
for the entire calendar year. In no event shall Landlord be entitled to receive
from Tenant and any other tenants in the Building an aggregate amount in excess
of actual Operating Expenses as a result of the foregoing provision.

        4.2 BASE RENT.

             4.2.1. Rent Adjustment. During the Lease Term, Tenant shall pay to
Landlord as rental for the Premises the Base Rent described in Section 1.8
above, subject to adjustment (herein called the "Rent Adjustment") as follows:
per the Base Rent schedule in Section 1.8 above.

             4.2.2. Tax and Operating Expense Adjustment. In addition to the
Rent Adjustment, during each calendar year subsequent to the Base Year, the Base
Rent shall be increased by (collectively, the "Tax and Operating Expense
Adjustment"): (i) Tenant's Percentage Share of the total dollar increase, if
any, in Property Taxes for such year over Property Taxes for the Base Year; and
(ii) Tenant's Percentage Share of the total dollar increase, if any, in
Operating Expenses paid or incurred by Landlord during such year over Operating
Expenses paid or incurred by Landlord during the Base Year. A decrease in
Property Taxes or Operating Expenses below the Base Year amounts shall not
decrease the amount of the Base Rent due hereunder or give rise to a credit in
favor of Tenant.

             4.2.3. Tax Exempt Tenant. If Tenant's Additional Rent as finally
determined for any calendar year exceeds the total payments made by Tenant on
account thereof, Tenant shall pay Landlord the deficiency within ten (10) days
of Tenant's receipt of Landlord's statement. If the total payments made by
Tenant on account thereof exceed Tenant's Additional Rent as finally determined
for such year, Tenant's excess payment shall be credited toward the rent next
due from Tenant under this Lease. For any partial calendar year at the beginning
or end of the Term, Additional Rent shall be prorated on the basis of a 365-day
year by computing Tenant's Share of the increases in Operating Costs and Taxes
for the entire year and then prorating such amount for the number of days during
such year included in the Term. Notwithstanding the termination of this Lease,
Landlord shall pay to Tenant or Tenant shall pay

<PAGE>   10

to Landlord, as the case may be, within ten (10) days after Tenant's receipt of
Landlord's final statement for the calendar year in which this Lease terminates,
the difference between Tenant's Additional Rent for that year, as finally
determined by Landlord, and the total amount previously paid by Tenant on
account thereof.

        If for any reason Base Taxes or Taxes for any year during the Term are
reduced, refunded or otherwise changed, Tenant's Additional Rent shall be
reduced, refunded or adjusted accordingly. If Taxes are temporarily reduced as a
result of space in the Building being leased to a tenant that is entitled to an
exemption from property taxes or other taxes, then for purposes of determining
Additional Rent for each year in which Taxes are reduced by any such exemption,
Taxes for such year shall be calculated on the basis of the amount the Taxes for
the year would have been in the absence of the exemption. The obligations of
Landlord to refund any overpayment of Additional Rent and of Tenant to pay any
Additional Rent not previously paid shall survive the expiration of the Term.
Notwithstanding anything to the contrary in this Lease, if there is at any time
a decrease in Taxes below the amount of the Taxes for the Base Year, then for
purposes of calculating Additional Rent for the year in which such decrease
occurs and all subsequent periods, Base Taxes shall be reduced to equal the
Taxes for the year in which the decrease occurs.

        4.3 ADJUSTMENT PROCEDURE; ESTIMATES. The Tax and Operating Expense
Adjustment shall be determined and paid as follows:

             4.3.1. Estimates. During each calendar year subsequent to the Base
Year, Landlord shall give Tenant written notice of its estimate of any increased
amounts payable under Section 4.2.2 for that calendar year. On or before the
first day of each calendar month during the calendar year, Tenant shall pay to
Landlord one-twelfth (1/12th) of such estimated amounts; provided, however,
that, not more often than quarterly, Landlord may, by written notice to Tenant,
revise its estimate for such year, and subsequent payments by Tenant for such
year shall be based upon such revised estimate.

             4.3.2. Landlord's Statement. Within one hundred twenty (120) days
after the close of each calendar year or as soon thereafter as is practicable,
Landlord shall deliver to Tenant a statement of that year's Property Taxes and
Operating Expenses, and the actual Tax and Operating Expense Adjustment to be
made pursuant to Section 4.2.2 for such calendar year, as determined by Landlord
(the "Landlord's Statement"). Such Landlord's Statement shall be binding upon
Tenant, except as specifically provided in Section 4.4 below. If the amount of
the actual Tax and Operating Expense Adjustment is more than the estimated
payments for such calendar year made by Tenant, Tenant shall pay the deficiency
to Landlord within five (5) days of receipt of Landlord's Statement. If the
amount of the actual Tax and Operating Expense Adjustment is less than the
estimated payments for such calendar year made by Tenant, any excess shall be
credited against Rent (as hereinafter defined) next payable by Tenant under this
Lease or, if the Lease Term has expired, any excess shall be paid to Tenant. No
delay in providing the Statement shall act as a waiver of Landlord's right to
increase in payment pursuant to the Tax and Operating Expense Adjustment.

             4.3.3. Termination. If this Lease shall terminate on a day other
than the end of a calendar year, the amount of the Tax and Operating Expense
Adjustment to be paid that is applicable to the calendar year in which such
termination occurs shall be prorated on the basis of the number of days from
January 1 of the calendar year to the termination date bears to 365. The
termination of this Lease shall not affect the obligations of Landlord and
Tenant pursuant to Section 4.3.2 to be performed after such termination.

        4.4 REVIEW OF LANDLORD'S STATEMENT. Provided that Tenant is not then in
default beyond any applicable cure period of its obligations to pay Base Rent,
additional rent described in Section 4.2.2 or any other payments required to be
made by it under this Lease, and provided further that Tenant strictly complies
with the provisions of this Section 4.4, Tenant shall have the right, once each
calendar year, to reasonably review supporting data for any portion of a
Landlord's Statement (provided, however, Tenant may not have an audit or review
right to all documentation relating to Building operations as this would far
exceed the relevant information necessary to properly document a pass-through
billing statement, but real estate tax statements, and information on utilities,
repairs, maintenance and insurance will be available), in accordance with the
following procedure:

<PAGE>   11

             4.4.1. Notice. Tenant shall, within ten (10) business days after
any such Landlord's Statement is delivered, deliver a written notice to Landlord
specifying the portions of the Landlord's Statement that are claimed to be
incorrect, and Tenant shall simultaneously pay to Landlord all amounts due from
Tenant to Landlord as specified in the Landlord's Statement, Except as expressly
set forth below, in no event shall Tenant be entitled to withhold, deduct, or
offset any monetary obligation of Tenant to Landlord under the Lease (including,
without limitation, Tenant's obligation to make all payments of Base Rent and
all payments of Tenant's Tax and Operating Expense Adjustment) pending the
completion of and regardless of the results of any review of records under this
Section 4.4. The right of Tenant under this Section 4.4 may only be exercised
once for any Landlord's Statement, and if Tenant fails to meet any of the above
conditions as a prerequisite to the exercise of such right, the right of Tenant
under this Section 4.4 for a particular Landlord's Statement shall be deemed
waived.

             4.4.2. Records. Tenant acknowledges that Landlord maintains its
records for the Building at Landlord's manager's corporate offices presently
located at the address set forth in Section 1.12 and Tenant agrees that any
review of records under this Section 4.4 shall be at the sole expense of Tenant
and shall be conducted by an independent firm of certified public accountants of
national standing. Tenant acknowledges and agrees that any records reviewed
under this Section 4.4 constitute confidential information of Landlord, which
shall not be disclosed to anyone other than the accountants performing the
review and the principals of Tenant who receive the results of the review. The
disclosure of such information to any other person, whether or not caused by the
conduct of Tenant, shall constitute a material breach of this Lease.

             4.4.3. Landlord's Review; Reconciliation. Any errors disclosed by
the review shall be promptly corrected by Landlord, provided, however, that if
Landlord disagrees with any such claimed errors, Landlord shall have the right
to cause another review to be made by an independent form of certified public
accountants of national standing. In the event of a disagreement between the two
accounting firms, the review that discloses the least amount of deviation from
the Landlord's Statement shall be deemed to be correct. In the event that the
results of the review of records (taking into account, if applicable, the
results of any additional review caused by Landlord) reveal that Tenant has
overpaid obligations for a preceding period, the amount of such overpayment
shall be credited against Tenant's subsequent installment obligations to pay the
estimated Tax and Operating Expense Adjustment. In the event that such results
show that Tenant has underpaid its obligations for a preceding period, Tenant
shall be liable for Landlord's actual accounting fees, and the amount of such
underpayment shall be paid by Tenant to Landlord with the next succeeding
installment obligation of estimated Tax and Operating Expense Adjustment.

        4.5 PAYMENT. Concurrently with the execution hereof, Tenant shall pay
Landlord Base Rent for the first calendar month of the Lease Term. Thereafter
the Base Rent described in Section 1.8, as adjusted in accordance with Section
4.2, shall be payable in advance on the first day of each calendar month. If the
Commencement Date is other than the first day of a calendar month, the prepaid
Base Rent for such partial month shall be prorated in the proportion that the
number of days this Lease is in effect during such partial month bears to the
total number of days in the calendar month. All Rent, and all other amounts
payable to Landlord by Tenant pursuant to the provisions of this Lease, shall be
paid to Landlord, without notice, demand, abatement, deduction or offset, in
lawful money of the United States at Landlord's office in the Building or to
such other person or at such other place as Landlord may designate from time to
time by written notice given to Tenant. No payment by Tenant or receipt by
Landlord of a lesser amount than the correct Rent due hereunder shall be deemed
to be other than a payment on account; nor shall any endorsement or statement on
any check or any letter accompanying any check or payment be deemed to effect or
evidence an accord and satisfaction; and Landlord may accept such check or
payment without prejudice to Landlord's right to recover the balance or pursue
any other remedy in this Lease or at law or in equity provided.

        4.6 LATE CHARGE; INTEREST. Tenant acknowledges that the late payment of
Base Rent or any other amounts payable by Tenant to Landlord hereunder (all of
which shall constitute additional rental to the same extent as Base Rent) will
cause Landlord to incur administrative costs and other damages, the exact amount
of which would be impracticable or extremely difficult to ascertain. Landlord
and Tenant agree that if Landlord does not receive any such payment on or before
five (5) days after the date the payment is due, Tenant shall pay to Landlord,
as additional rent, (a) a late charge equal to five percent (5%) of the overdue
amount to

<PAGE>   12

cover such additional administrative costs; and (b) interest on the delinquent
amounts at the lesser of the maximum rate permitted. by law (if any) or twelve
percent (12%) per annum from the date due to the date paid.

        4.7 ADDITIONAL RENT. For purposes of this Lease, all amounts payable by
Tenant to Landlord pursuant to this Lease, whether or not denominated as such,
shall constitute additional rental hereunder. Such additional rental, together
with the Base Rent, Rent Adjustment, and Tax and Operating Expense Adjustment,
shall sometimes be referred to in this Lease as "Rent".

        4.8 ADDITIONAL TAXES. Notwithstanding anything in Section 4.1.2 to the
contrary, Tenant shall reimburse Landlord upon demand for any and all taxes
payable by or imposed upon Landlord upon or with respect to: any fixtures or
personal property located in the Premises; any leasehold improvements made in or
to the Premises by or for Tenant; the Rent payable hereunder, including, without
limitation, any gross receipts tax, license fee or excise tax levied by any
governmental authority; the possession, leasing, operation, management,
maintenance, alteration, repair, use or occupancy of any portion of the Premises
(including without limitation any applicable possessory interest taxes); or this
transaction or any document to which Tenant is a party creating or transferring
an interest or an estate in the Premises.

                          ARTICLE V - SECURITY DEPOSIT

        Upon the execution of this Lease, Tenant shall deposit with Landlord the
Security Deposit described in Section 1.10 above. The Security Deposit is made
by Tenant to secure the faithful performance of all the terms, covenants and
conditions of this Lease to be performed by Tenant. If Tenant shall default with
respect to any covenant or provision hereof, Landlord may use, apply or retain
all or any portion of the Security Deposit to cure such default or to compensate
Landlord for any loss or damage which Landlord may suffer thereby. If Landlord
so uses or applies all or any portion of the Security Deposit, Tenant shall
immediately upon written demand deposit cash with Landlord in an amount
sufficient to restore the Security Deposit to the full amount hereinabove
stated. Landlord shall not be required to keep the Security Deposit separate
from its general accounts and Tenant shall not be entitled to interest on the
Security Deposit. Within thirty (30) days after the expiration of the Lease Term
and the vacation of the Premises by Tenant, the Security Deposit, or such part
as has not been applied to cure any default of Tenant, shall be returned to
Tenant.

                          ARTICLE VI - USE OF PREMISES

        6.1 TENANT'S PERMITTED USE. Tenant shall use the Premises only for
Tenant's Permitted Use as set forth in Section 1.11 above and shall not use or
permit the Premises to be used for any other purpose. Tenant shall, at its sole
cost and expense, obtain all governmental licenses and permits required to allow
Tenant to conduct Tenant's Permitted Use. Landlord disclaims any warranty that
the Premises are suitable for Tenant's use and Tenant acknowledges that it has
had a full opportunity to make its own determination in this regard.

        6.2 COMPLIANCE WITH LAWS AND OTHER REQUIREMENTS.

             6.2.1. Applicable Law. Tenant shall cause the Premises to comply in
all material respects with all laws, ordinances, regulations and directives of
any governmental authority having jurisdiction including, without limitation,
any certificate of occupancy and any law, ordinance, regulation, covenant,
condition or restriction affecting the Building or the Premises which in the
future may become applicable to the Premises (collectively "Applicable Law").

             6.2.2. No Violation. Tenant shall not use the Premises, or permit
the Premises to be used, in any manner which: (a) violates any Applicable Law;
(b) causes or is reasonably likely to cause damage to the Building or the
Premises; (c) violates a requirement or condition of any fire and extended
insurance policy covering the Building and/or the Premises, or increases the
cost of such policy; (d) constitutes or is reasonably likely to constitute a
nuisance, annoyance or inconvenience to other tenants or occupants of the
Building or its equipment, facilities or systems; (e) interferes with, or is
reasonably likely to interfere with, the transmission or reception of microwave,
television, radio, telephone or other communication

<PAGE>   13

signals by antennae or other facilities located in the Building; or (f) violates
the Rules and Regulations described in Article XVIII.

             6.3 HAZARDOUS MATERIALS.

                  6.3.1. Prohibition. No Hazardous Materials (as defined
herein), shall be Handled (as also deemed herein), upon, about, above or beneath
the Premises or any portion of the Building by or on behalf of Tenant, its
subtenants or its assignees, or their respective contractors, clients, officers,
directors, employees, agents, or invitees. Any such Hazardous Materials so
Handled shall be known as Tenant's Hazardous Materials. Notwithstanding the
foregoing, normal quantities of Tenant's Hazardous Materials customarily used in
the conduct of general administrative and executive office activities (e.g.,
copier fluids and cleaning supplies) may be Handled at the Premises without
Landlord's prior written consent. Tenant's Hazardous Materials shall be Handled
at all times in compliance with the manufacturer's instructions therefor and all
applicable Environmental Law (as defined herein).

                  6.3.2. Remediation. Notwithstanding the obligation of Tenant
to indemnify Landlord pursuant to this Lease, Tenant shall, at its sole cost and
expense, promptly take all actions required by any Regulatory Authority (as
defined herein), or necessary for Landlord to make full economic use of the
Premises or any portion of the Building, which requirements or necessity arises
from the Handling of Tenant's Hazardous Materials upon, about, above or beneath
the Premises or any portion of the Building. Such actions shall include, but not
be limited to, the investigation of the environmental condition of the Premises
or any portion of the Building, the preparation of any feasibility studies or
reports and the performance of any cleanup, remedial, removal or restoration
work. Tenant shall take all actions necessary to restore the Premises or any
portion of the Building to the condition existing prior to the introduction of
Tenant's Hazardous Materials, notwithstanding any less stringent standards or
remediation allowable under applicable Environmental Laws. Tenant shall
nevertheless obtain Landlord's written approval prior to undertaking any actions
required by this Section, which approval shall not be unreasonably withheld so
long as such actions would not potentially have a material adverse long-term or
short-term effect on the Premises or any portion of the Building.

                  6.3.3. Additional Documents. Tenant agrees to execute
affidavits, representations, and the like from time to time at Landlord's
request stating Tenant's best knowledge and belief regarding the presence of
Hazardous Materials on the Premises.

                  6.3.4. Environmental Laws. As used herein, "Environmental
Laws" means and includes all now and hereafter existing statutes, laws,
ordinances, codes, regulations, rules, rulings, orders, decrees, directives,
policies and requirements by any Regulatory Authority regulating, relating to,
or imposing liability or standards of conduct concerning public health and
safety or the environment.

                  6.3.5. Hazardous Materials. As used herein, "Hazardous
Materials" means: (a) any material or substance: (i) which is defined or becomes
defined as a "hazardous substance", "hazardous waste," "infectious waste,"
"chemical mixture or substance," or "air pollutant" under Environmental Laws;
(ii) containing petroleum, crude oil or any fraction thereof; (iii) containing
polychlorinated biphenyls (PCB's); (iv) containing asbestos; (v) which is
radioactive; or (vi) which is infectious; or (b) any other material or substance
displaying toxic, reactive, ignitable or corrosive characteristics, as all such
terms are used in their broadest sense, and are defined, or become defined by
environmental laws; or (c) materials which cause a nuisance upon or waste to the
Premises or any portion of the Building.

                  6.3.6. Handle. As used herein, "Handle," "handle," "Handled,"
"handled," "Handling," or "handling" shall mean any installation, handling,
generation, storage, treatment, use, disposal, discharge, release, manufacture,
refinement, presence, migration, emission, abatement, removal, transportation,
or any other activity of any type in connection with or involving Hazardous
Materials.

                  6.3.7. Regulatory Authority. As used herein, "Regulatory
Authority" shall mean any federal, state or local governmental agency,
commission, board or political subdivision.

<PAGE>   14

                      ARTICLE VII - UTILITIES AND SERVICES

        7.1 BUILDING SERVICES. As long as Tenant is not in monetary default
under this Lease, Landlord agrees to furnish or cause to be furnished to the
Premises the following utilities and services, subject to the conditions and
standards set forth herein:

             7.1.1. Elevator Service. Non-attended automatic elevator service
(if the Building has such equipment serving the Premises), in common with
Landlord and other tenants and occupants and their agents and invitees.

             7.1.2. HVAC. During Business Hours, such air conditioning, heating
and ventilation as, in Landlord's reasonable judgment, are required for the
comfortable use and occupancy of the Premises; provided, however, that if Tenant
shall require heating, ventilation or air conditioning in excess of that which
Landlord shall be required to provide hereunder, Landlord may provide such
additional heating, ventilation or air conditioning at such rates and upon such
additional conditions as shall be determined by Landlord from time to time.

             7.1.3. Water. Water for drinking and if rest rooms are within the
Premises, rest room purposes.

             7.1.4. Janitorial and Cleaning. Reasonable janitorial and cleaning
services, provided that the Premises are used exclusively for office purposes
and are kept reasonably in order by Tenant. If the Premises are not used
exclusively as offices, Landlord, at Landlord's sole discretion, may require
that the Premises be kept clean and in order by Tenant, at Tenant's expense, to
the satisfaction of Landlord and by persons approved by Landlord; and, in all
events, Tenant shall pay to Landlord the cost of removal of Tenant's refuse and
rubbish, to the extent that the same exceeds the refuse and rubbish attendant to
normal office usage.

             7.1.5. Electricity. At all reasonable times, electric current as
required for building standard lighting and fractional horsepower office
machines; provided, however, that: (i) without Landlord's consent, Tenant shall
not install, or permit the installation, in the Premises of any computers, word
processors, electronic data processing equipment or other type of equipment or
machines which will increase Tenant's use of electric current in excess of that
which Landlord is obligated to provide hereunder (provided, however, that the
foregoing shall not preclude the use of personal computers or similar office
equipment); (ii) if Tenant shall require electric current which may disrupt the
provision of electrical service to other tenants, Landlord may refuse to grant
its consent or may condition its consent upon Tenant's payment of the cost of
installing and providing any additional facilities required to furnish such
excess power to the Premises and upon the installation in the Premises of
electric current meters to measure the amount of electric current consumed, in
which latter event Tenant shall pay for the cost of such meter(s) and the cost
of installation, and repair thereof, as well as for all excess electric current
consumed at the rates charged by the applicable local public utility, plus a
reasonable amount to cover the additional expenses incurred by Landlord in
keeping account of the electric current so consumed; and (iii) if Tenant's
increased electrical requirements will materially affect the temperature level
in the Premises or the Building, Landlord's consent may be conditioned upon
Tenant's requirement to pay such amounts as will be incurred by Landlord to
install and operate any machinery or equipment necessary to restore the
temperature level to that otherwise required to be provided by Landlord,
including but not limited to the cost of modifications to the air conditioning
system. Landlord shall not, in any ways be liable or responsible to Tenant for
any loss or damage or expense which Tenant may incur or sustain if, for any
reasons beyond Landlord's reasonable control, either the quantity or character
of electric service is changed or is no longer available or suitable for
Tenant's requirements. Tenant covenants that at all times its use of electric
current shall never exceed the capacity of the feeders, risers or electrical
installations of the Building. If submetering of electricity in the Building
will not be permitted under future laws or regulations, the Rent will then be
equitably and periodically adjusted to include an additional payment to Landlord
reflecting the cost to Landlord for furnishing electricity to Tenant in the
Premises.

             7.1.6. Payments. Any amounts which Tenant is required to pay to
Landlord pursuant to this Section 7. l shall be payable upon demand by Landlord
and shall constitute additional rent.

<PAGE>   15

        7.2 INTERRUPTION OF SERVICE. Landlord shall not be liable for any
failure to furnish, stoppage of, or interruption in furnishing any of the
services or utilities described in Section 7.1, when such failure is caused by
accident, breakage, repairs, strikes, lockouts, labor disputes, labor
disturbances, governmental regulation, civil disturbances, acts of war,
moratorium or other governmental action, or any other cause beyond Landlord's
reasonable control, and, in such event, Tenant shall not be entitled to any
damages nor shall any failure or interruption abate or suspend Tenant's
obligation to pay Rent, Base Rent and additional rent required under this Lease
or constitute or be construed as a constructive or other eviction of Tenant.
Further, in the event any governmental authority or public utility promulgates
or revises any law, ordinance, rule or regulation, or issues mandatory controls
or voluntary controls relating to the use or conservation of energy, water, gas,
light or electricity, the reduction of automobile or other emissions, or the
provision of any other utility or service, Landlord may take any reasonably
appropriate action to comply with such law, ordinance, rule, regulation,
mandatory control or voluntary guideline and Tenant's obligations hereunder
shall not be affected by any such action of Landlord. The parties acknowledge
that safety and security devices, services and programs provided by Landlord, if
any, while intended to deter crime and ensure safety, may not in given instances
prevent theft or other criminal acts, or ensure safety of persons or property.
The risk that any safety or security device, service or program may not be
effective, or may malfunction, or be circumvented by a criminal, is assumed by
Tenant with respect to Tenant's property and interests, and Tenant shall obtain
insurance coverage to the extent Tenant desires protection against such criminal
acts and other losses, as further described in this Lease. Tenant agrees to
cooperate in any reasonable safety or security program developed by Landlord or
required by Law.

        7.3 UTILITY DEREGULATION.

             7.3.1. Landlord Controls Selection. Landlord has advised Tenant
that presently Pacific Gas & Electric ("Electric Service Provider") is the
utility company selected by Landlord to provide electricity service for 44
Montgomery Skeet. Notwithstanding the foregoing, if permitted by law, Landlord
shall have the right at any time and from time to time during the Lease Term to
either contract for service from a different company or companies providing
electricity service (each such company shall hereinafter be referred to as an
"Alternate Service Provider") or continue to contract for service from the
Electric Service Provider.

             7.3.2. Tenant Shall Give Landlord Access. Tenant shall cooperate
with Landlord, the Electric Service Provider, and any Alternate Service Provider
at all times and, as reasonably necessary, shall allow Landlord, Electric
Service Provider, and any Alternate Service Provider reasonable access to 44
Montgomery Street's electric lines, feeders, risers, wiring and any other
machinery within the Premises.

                     ARTICLE VIII - MAINTENANCE AND REPAIRS

        8.1 LANDLORD'S OBLIGATIONS. Except as expressly provided in Sections 8.2
and 8.3 below, Landlord shall maintain the Building in reasonable order and
repair throughout the Lease Term; provided, however, that Landlord shall not be
liable for any failure to make any repairs or to perform any maintenance unless
such failure shall persist for an unreasonable time after written notice of the
need for such repairs or maintenance is given to Landlord by Tenant. Except as
provided in Article XI, there shall be no abatement of Rent, nor shall there be
any liability of Landlord, by reason of any injury or inconvenience to, or
interference with, Tenant's business or operations arising from the making of,
or failure to make, any maintenance or repairs in or to any portion of the
Building.

        8.2 TENANT'S OBLIGATIONS. During the Lease Term, Tenant shall, at its
sole cost and expense, maintain the Premises in good order and repair
(including, without limitation, the carpet, wall-covering, doors, plumbing and
other fixtures, equipment, alterations and improvements, whether installed by
Landlord or Tenant). Further, Tenant shall be responsible for, and upon demand
by Landlord shall promptly reimburse Landlord for, any damage to any portion of
the Building or the Premises caused by (a) Tenant's activities in the Building
or the Premises; (b) the performance or existence of any alterations, additions
or improvements made by Tenant in or to the Premises; (c) the installation, use,
operation or movement of Tenant's property in or about the Building or the
Premises; or (d) any act or omission by Tenant or its officers, partners,
employees, agents, contractors or invitees.

<PAGE>   16

        8.3 LANDLORD'S RIGHTS. Landlord and its contractors shall have the
right, at all reasonable times and upon prior written, oral or telephonic notice
to Tenant at the Premises, other than in the case of any emergency in which case
no notice shall be required, to enter upon the Premises to make any repairs to
the Premises or the Building reasonably or deemed reasonably necessary by
Landlord and to erect such equipment, including scaffolding, as is reasonably
necessary to effect such repairs.

              ARTICLE IX - ALTERATIONS, ADDITIONS AND IMPROVEMENTS

        9.1 LANDLORD'S CONSENT; CONDITIONS. Tenant shall not make or permit to
be made any alterations, additions, or improvements in or to the Premises
("Alterations") without the prior written consent of Landlord, which consent,
with respect to non-structural alterations, shall not be unreasonably withheld,
and which consent with respect to any alterations which may affect the
structural or safety components of the Building, may be given or withheld in
Landlord's sole and absolute discretion. Landlord may impose as a condition to
making any Alterations such requirements as Landlord in its sole discretion
deems necessary or desirable including without limitation: Tenant's submission
to Landlord, for Landlord's prior written approval, of all plans and
specifications relating to the Alterations; Landlord's prior written approval of
the time or times when the Alterations are to be performed; Landlord's prior
written approval of the contractors and subcontractors performing work in
connection with the Alterations; employment of union contractors and
subcontractors who shall not cause labor disharmony; Tenant's receipt of all
necessary permits and approvals from all governmental authorities having
jurisdiction over the Premises prior to the construction of the Alterations;
Tenant's delivery to Landlord of such bonds and insurance as Landlord shall
reasonably require; and Tenant's payment to Landlord of all costs and expenses
incurred by Landlord because of Tenant's Alterations, including but not limited
to costs incurred in reviewing the plans and specifications for, and the
progress of, the Alterations. Tenant is required to provide Landlord written
notice of whether the Alterations include the Handling of any Hazardous
Materials and whether these materials are of a customary and typical nature for
industry practices. Upon completion of the Alterations, Tenant shall provide
Landlord with copies of as-built plans. Neither the approval by Landlord of
plans and specifications relating to any Alterations nor Landlord's supervision
or monitoring of any Alterations shall constitute any warranty by Landlord to
Tenant of the adequacy of the design for Tenant's intended use or the proper
performance of the Alterations.

        9.2 PERFORMANCE OF ALTERATIONS WORK. All work relating to the
Alterations shall be performed in compliance with the plans and specifications
approved by Landlord, all applicable laws, ordinances, rules, regulations and
directives of all governmental authorities having jurisdiction (including
without limitation Title 24 of the California Administrative Code) and the
requirements of all carriers of insurance on the Premises and the Building, the
Board of Underwriters, Fire Rating Bureau, or similar organization. All work
shall be performed in a diligent, first class manner and so as not to
unreasonably interfere with any other tenants or occupants of the Building. All
costs incurred by Landlord relating to the Alterations shall be payable to
Landlord by Tenant as additional rent upon demand. No asbestos-containing
materials shall be used or incorporated in the Alterations. No lead-containing
surfacing material, solder, or other construction materials or fixtures where
the presence of lead might create a condition of exposure not in compliance with
Environmental Laws shall be incorporated in the Alterations.

        9.3 LIENS. Tenant shall pay when due all costs for work performed and
materials supplied to the Premises. Tenant shall keep Landlord, the Premises and
the Building free from all liens, stop notices and violation notices relating to
the Alterations or any other work performed for, materials furnished to or
obligations incurred by or for Tenant and Tenant shall protect, indemnify, hold
harmless and defend Landlord, the Premises and the Building of and from any and
all loss, cost, damage, liability and expense, including attorneys' fees,
arising out of or related to any such liens or notices. Further, Tenant shall
give Landlord not less than seven (7) business days prior written notice before
commencing any Alterations in or about the Premises to permit Landlord to post
appropriate notices of non-responsibility. Tenant shall also secure, prior to
commencing any Alterations, at Tenant's sole expense, a completion and lien
indemnity bond satisfactory to Landlord for such work. During the progress of
such work, Tenant shall, upon Landlord's request, furnish Landlord with sworn
contractor's statements and lien waivers covering all work theretofore
performed. Tenant shall satisfy or otherwise discharge all liens, stop notices
or other claims or encumbrances within ten (10) days after

<PAGE>   17

Landlord notifies Tenant in writing that any such lien, stop notice, claim or
encumbrance has been filed. If Tenant fails to pay and remove such lien, claim
or encumbrance within such ten (10) days, Landlord, at its election, may pay and
satisfy the same and in such event the sums so paid by Landlord, with interest
from the date of payment at the rate set forth in this Lease for amounts owed
Landlord by Tenant shall be deemed to be additional rent due and payable by
Tenant at once without notice or demand.

        9.4 LEASE TERMINATION. Except as provided herein, upon expiration or
earlier termination of this Lease Tenant shall surrender the Premises to
Landlord in the same condition as existed on the date Tenant first occupied the
Premises (whether pursuant to this Lease or an earlier lease), subject to
reasonable wear and tear. All Alterations shall become a part of the Premises
and shall become the property of Landlord upon the expiration or earlier
termination of this Lease, unless Landlord shall, by written notice given to
Tenant, require Tenant to remove some or all of Tenant's Alterations, in which
event Tenant shall promptly remove the designated Alterations and shall promptly
repair any resulting damage, all at Tenant's sole expense. All business and
trade fixtures, machinery and equipment, furniture, movable partitions and items
of personal property owned by Tenant or installed by Tenant at its expense in
the Premises shall be and remain the property of Tenant, upon the expiration or
earlier termination of this Lease, Tenant shall, at its sole expense, remove all
such items and repair any damage to the Premises or the Building caused by such
removal. If Tenant fails to remove any such items or repair such damage promptly
after the expiration or earlier termination of the Lease, Landlord may, but need
not, do so with no liability to Tenant, and Tenant shall pay Landlord the cost
thereof upon demand. Notwithstanding the foregoing to the contrary, in the event
that Landlord gives its consent, pursuant to the provisions of this Article IX,
to allow Tenant to make an Alteration in the Premises, Landlord agrees, upon
Tenant's written request, to notify Tenant in writing at the time of the giving
of such consent whether Landlord will require Tenant, at Tenant's cost, to
remove such Alteration at the end of the Lease Term.

                    ARTICLE X - INDEMNIFICATION AND INSURANCE

        10.1 INDEMNIFICATION.

             10.1.1.Tenant. Tenant agrees to protect, indemnify, hold harmless
and defend Landlord and any Mortgagee, as defined herein, and each of their
respective partners, directors, officers, agents and employees, successors and
assigns (except to the extent the losses described below are caused by the gross
negligence or intentional misconduct of Landlord, its agents and employees),
from and against:

                  (i) any and all loss, cost, damage, liability or expense as
incurred (including but not limited to reasonable attorneys' fees and legal
costs) arising out of or related to any claim, suit or judgment brought by or in
favor of any person or persons for damage, loss or expense due to, but not
limited to, bodily injury, including death or property damage sustained by such
person or persons which arises out of, is occupied by or is in any way
attributable to the use or occupancy of the Premises or any portion of the
Building by Tenant or the acts or omissions of Tenant or its agents, employees,
contractors, clients, invitees or subtenants except that caused by the sole
active negligence or willful misconduct of Landlord or its agents or employees
Such loss or damage shall include, but not be limited to, any injury or damage
to, or death of, Landlord's employees or agents or damage to the Premises or any
portion of the Building.

                  (ii) any and all environmental damages which arise from: (a)
the Handling of any Tenants Hazardous Materials, as defined in Section 6.3 or
(b) the breach of any of the provisions of this Lease. For the purpose of this
Lease, "environmental damages" shall mean (x) all claims, judgments, damages,
penalties, fines, costs, liabilities, and losses (including without limitation,
diminution in the value of the Premises or any portion of the Building, damages
for the loss of or restriction on use of rentable or usable space or of any
amenity of the Premises or any portion of the Building, and from any adverse
impact of Landlord's marketing of space); (y) all reasonable sums paid for
settlement of claims, attorneys' fees, consultants' fees and experts' fees; and
(z) all costs incurred by Landlord in connection with investigation or
remediation relating to the Handling of Tenant's Hazardous Materials, whether or
not required by Environmental Laws, necessary for Landlord to make full economic
use of the Premises or any portion of the Building, or otherwise required under
this Lease. To the extent that Landlord is held strictly liable by a court or
other governmental agency of

<PAGE>   18

competent jurisdiction under any Environmental Laws, Tenant's obligation to
Landlord and the other indemnities under the foregoing indemnification shall
likewise be without regard to fault on Tenant's part with respect to the
violation of any Environmental Law which results in liability to the indemnitee.
Tenant's obligations and liabilities pursuant to this Section 10.1 shall survive
the expiration or earlier termination of this Lease.

             10.1.2.Landlord. Landlord agrees to protect, indemnify, hold
harmless and defend Tenant from and against any and all loss, cost, damage,
liability or expense, including reasonable attorneys' fees, with respect to any
claim of damage or injury to persons or property at the Premises, caused by the
gross negligence or intentional misconduct of Landlord or its authorized agents
or employees.

             10.1.3.No Limitation. Notwithstanding anything to the contrary
contained herein, nothing shall be interpreted or used to (a) in any way affect,
limit, reduce or abrogate any insurance coverage provided by any insurers to
either Tenant or Landlord, or (b) infer or imply that Tenant is a partner, joint
venturer, agent, employee, or otherwise acting by or at the direction of
Landlord.

        10.2 PROPERTY INSURANCE.

             10.2.1.Tenant All-Risk. At all times during the Lease Term, Tenant
shall procure and maintain, at its sole expense, "all-risk" property insurance,
for damage or other loss caused by fire or other casualty or cause including,
but not limited to, vandalism and malicious mischief, theft, water damage of any
type, including sprinkler leakage, bursting of pipes, and explosion, in an
amount not less than one hundred percent (100%) of the replacement cost covering
(a) all Alterations made by or for Tenant in the Premises; and (b) Tenant's
trade fixtures, equipment and other personal property from time to time situated
in the Premises. The proceeds of such insurance shall be used for the repair or/
replacement of the property so insured, except that if not so applied or if this
Lease is terminated following a casualty, the proceeds applicable to the
leasehold improvements shall be paid to Landlord and the proceeds applicable to
Tenant's personal property shall be paid to Tenant.

             10.2.2.Tenant Business Interruption. At all times during the Lease
Term, Tenant shall procure and maintain business interruption insurance in such
amount as will reimburse Tenant for direct or indirect loss of earnings
attributable to all perils insured against in Section 10.2.1.

             10.2.3.Landlord All-Risk. Landlord shall, at all times during the
Lease Term, procure and maintain "all-risk" property insurance in the amount not
less than ninety percent (90%) of the insurable replacement cost covering the
Building in which the Premises are located and such other insurance as may be
required by a Mortgagee or otherwise desired by Landlord.

        10.3 LIABILITY INSURANCE.

             10.3.1.Tenant. At all times during the Lease Term, Tenant shall
procure and maintain, at its sole expense, commercial general liability
insurance applying to the use and occupancy of the Premises and the business
operated by Tenant. Such insurance shall have a minimum combined single limit of
liability of at least Two Million Dollars ($2,000,000) per occurrence and a
general aggregate limit of at least Two Million Dollars ($2,000,000). All such
policies shall be written to apply to all bodily injury, property damage, and
personal injury losses, and shall be endorsed to include Landlord and its
agents, beneficiaries, partners, employees, and any deed of trust holder or
mortgagee of Landlord or any ground lessor as additional insureds. Such
liability insurance shall be written as primary policies, not excess or
contributing with or secondary to any other insurance as may be available to the
additional insureds.

             10.3.2. Alcohol. Prior to the sale, storage, use or giving away of
alcoholic beverages on or from the Premises by Tenant or another person, Tenant,
at its own expense, shall obtain a policy or policies of insurance issued by a
responsible insurance company and in a form acceptable to Landlord saving
harmless and protecting Landlord and the Premises against any and all damages,
claims, liens, judgments, expenses and costs, including actual attorneys' fees,
arising under any present or future law, statute, or ordinance of the State of
California or other

<PAGE>   19

governmental authority having jurisdiction of the Premises, by reason of any
storage, sale, use or giving away of alcoholic beverages on or from the
Premises. Such policy or policies of insurance shall have a minimum combined
single limit of One Million Dollars ($1,000,000) per occurrence and shall apply
to bodily injury, fatal or nonfatal; injury to means of support; and injury to
property of any person. Such policy or policies of insurance shall name Landlord
and its agents, beneficiaries, partners, employees and any mortgagee of Landlord
or any ground lessor of Landlord as additional insureds.

             10.3.3.Estimates. Landlord shall, at all during the Lease Term,
procure and maintain commercial general liability insurance for the Building in
which the Premises are located. Such insurance shall have minimum combined
single limit of liability of at least Two Million Dollars ($2,000,000) per
occurrence, and a general aggregate limit of at least Two Million Dollars
($2,000,000).

        10.4 WORKERS' COMPENSATION INSURANCE. At all times during the Lease
Term, Tenant shall procure and maintain Workers' Compensation Insurance in
accordance with the laws of the State of California, and Employer's Liability
insurance with a limit not less than One Million Dollars ($1,000,000) Bodily
Injury Each Accident; One Million Dollars ($1,000,000) Bodily Injury By Disease
- Each Person; -- and One Million Dollars ($ 1,000,000) Bodily Injury to Disease
- Policy Limit.

        10.5 POLICY REQUIREMENTS. All insurance required to be maintained by
Tenant shall be issued by insurance companies authorized to do insurance
business in the State of California and rated not less than A-VIII in Best's
Insurance Guide. A certificate of insurance (or, at Landlord's option, copies of
the applicable policies) evidencing the insurance required under this Article X
shall be delivered to Landlord not less than thirty (30) days prior to the
Commencement Date. No such policy shall be subject to cancellation or
modification without thirty (30) days prior written notice to Landlord and to
any deed of trust holder, mortgagee or ground lessor designated by Landlord to
Tenant. Tenant shall furnish Landlord with a replacement certificate with
respect to any insurance not less than thirty (30) days prior to the expiration
of the current policy. Tenant shall have the right to provide the insurance
required by this Article X pursuant to blanket policies, but only if such
blanket policies expressly provide coverage to the Premises and Landlord as
required by this Lease pursuant to a per-location endorsement.

        10.6 WAIVER OF SUBROGATION. Each party hereby waives any right of
recovery against the other for injury or loss due to hazards covered by
insurance or required to be covered, to the extent of the injury or loss covered
thereby. Any policy of insurance to be provided by Tenant or Landlord pursuant
to this Article X shall contain a clause denying the applicable insurer any
right of subrogation against the other party.

        10.7 FAILURE TO INSURE. If Tenant fails to maintain any insurance which
Tenant is required to maintain pursuant to this Article X, Tenant shall be
liable to Landlord for any loss or cost resulting from such failure to maintain.
Tenant may not self-insure against any risks required to be covered by insurance
without Landlord's prior written consent, which consent may be given or withheld
in Landlord's sole and absolute discretion.

                       ARTICLE XI - DAMAGE OR DESTRUCTION

        11.1 TOTAL DESTRUCTION. Except as provided in Section 11.3 below, this
Lease shall, at Landlord's election, terminate if the Building is totally
destroyed.

        11.2 PARTIAL DESTRUCTION OF PREMISES. If the Premises are damaged by any
casualty and, in Landlord's opinion, the Premises (exclusive of any Alterations
made to the Premises by Tenant) can be restored to its pre-existing condition
within two hundred seventy (270) days after the date of the damage or
destruction, Landlord shall, upon written notice from Tenant to Landlord of such
damage, except as provided in Section 11.3, promptly and with due diligence
repair any damage to the Premises (exclusive of any Alterations to the Premises
made by Tenant, which shall be promptly repaired by Tenant at its sole expense)
and, until such repairs are completed, the Rent shall be abated from the date of
damage or destruction in the same proportion that the rentable area of the
portion of the Premises which is unusable by Tenant in the conduct of its
business bears to the total rentable area of the Premises. If such repairs
cannot, in Landlord's opinion, be made within said two hundred seventy (270) day
period, then Landlord

<PAGE>   20

may, at its option, exercisable by written notice given to Tenant within thirty
(30) days after the date of the damage or destruction, elect to make the repairs
within a reasonable time after the damage or destruction, in which event this
Lease shall remain in full force and effect but the Rent shall be abated as
provided in the preceding sentence; if Landlord does not so elect to make the
repairs, then either Landlord or Tenant shall have the right, by written notice
given to the other within sixty (60) days after the date of the damage or
destruction, to terminate this Lease as of the date of the damage or
destruction.

        11.3 EXCEPTIONS TO LANDLORD'S OBLIGATIONS. Notwithstanding anything to
the contrary contained in this Article XI, Landlord shall have no obligation to
repair the Premises if either: (a) the Building in which the Premises are
located is so damaged as to require repairs to the Building exceeding twenty
percent (20%) of the full insurable value of the Building; or (b) Landlord
elects to demolish the Building in which the Premises are located; or (c) the
damage or destruction occurs less than two (2) years prior to the Expiration
Date, exclusive of option periods. Further, Tenant's Rent shall not be abated if
either (i) the damage or destruction is repaired within five (5) business days
after Landlord receives written notice from Tenant of the casualty, or (ii)
Tenant, or any officers, partners, employees, agents or invitees of Tenant, or
any assignee or subtenant of Tenant, is, in whole or in part, responsible for
the damage or destruction. Notwithstanding the foregoing, Landlord shall make
such repairs if the entire damage can be repaired within ninety (90) days from
the date of partial destruction.

        11.4 WAIVER. The provisions contained in this Lease shall supersede any
laws (whether statutory, common law or otherwise) now or hereafter in effect
relating to damage, destruction, self-help or termination, including California
Civil Code Sections 1932 and 1933.

                           ARTICLE XII - CONDEMNATION

        12.1 TAKING. If the entire Premises or so much of the Premises as to
render the balance unusable by Tenant shall be taken by condemnation, sale in
lieu of condemnation or in any other manner for any public or quasi-public
purpose (collectively "Condemnation"), and if Landlord, at its option, is unable
or unwilling to provide substitute premises containing at least as much rentable
area as described in Section 1.2 above, then this Lease shall terminate on the
date that title or possession to the Premises is taken by the condemning
authority, whichever is earlier

        12.2 AWARD. In the event of any Condemnation, the entire award for such
taking shall belong to Landlord. Tenant shall have no claim against Landlord or
the award for the value of any unexpired term of this Lease or otherwise. Tenant
shall be entitled to independently pursue a separate award in a separate
proceeding for Tenant's relocation costs directly associated with the taking,
provided such separate award does not diminish Landlord's award.

        12.3 TEMPORARY TAKING. No temporary talking of the Premises shall
terminate this Lease or entitle Tenant to any abatement of the Rent payable to
Landlord under this Lease; provided, further, that any award for such temporary
taking shall belong to Tenant to the extent that the award applies to any time
period during the Lease Term and to Landlord to the extent that the award
applies to any time period outside the Lease Term.

                            ARTICLE XIII - RELOCATION

        Landlord shall have the right, at its option upon not less than thirty
(30) days prior written notice to Tenant, to relocate Tenant and to substitute
for the Premises described above and the premises which Tenant subleases from
Compaq Corporation commonly letdown as Suite 250 ("Sublease Premises"), other
space in the Building containing at least as much rentable area as the Premises
and Sublease Premises described in Section 1.2 above. If Tenant is already in
occupancy of the Premises, then Landlord shall approve in advance the relocation
expenses for purposes of reimbursement for Tenant's reasonable moving and
telephone relocation expenses and for reasonable quantities of new stationery
upon submission to Landlord of receipts for such expenditures incurred by
Tenant.

                     ARTICLE XIV - ASSIGNMENT AND SUBLETTING

        14.1 RESTRICTION. Without the prior written consent of Landlord, Tenant
shall not, either voluntarily or by operation of law, assign, encumber, or
otherwise transfer this Lease

<PAGE>   21

or any interest herein, or sublet the Premises or any part thereof, or permit
the Premises to be occupied by anyone other than Tenant or Tenant's employees
(any such assignment, encumbrance, subletting, occupation or transfer is
hereinafter referred to as a "Transfer"). For purposes of this Lease the term
"Transfer" shall also include (a) if Tenant is a partnership the withdrawal or
change, voluntary, involuntary or by operation of law, of a majority of the
partners, or a transfer of a majority of partnership interests, within a twelve
month period, or the dissolution of the partnership, and (b) if Tenant is a
closely held corporation (i.e. whose stock is not publicly held and not traded
through an exchange or over the counter) or a limited liability company, the
dissolution, merger, consolidation, division, liquidation or other
reorganization of Tenant, or within a twelve month period: (i) the sale or other
transfer of more than an aggregate of 50% of the voting securities of Tenant
(other than to immediate family members by reason of gift or death) or (ii) the
sale, mortgage, hypothecation or pledge of more than an aggregate of 50% of
Tenant's net assets. A Transfer in violation of the foregoing shall be void and,
at Landlord's option, shall constitute a material breach of this Lease.
Notwithstanding anything contained in this Article XIV to the contrary, Tenant
shall have the right to assign the Lease or sublease the Premises, or any part
thereof, to an "Affiliate" without the prior written consent of Landlord, but
upon at least twenty (20) days' prior written notice to Landlord, provided that
said Affiliate is not in default under any other lease for space in a property
that is owned by Landlord or managed by Seagate or any of its affiliates. For
purposes of this provision, the term "Affiliate" shall mean any corporation or
other entity controlling, controlled by, or under common control with (directly
or indirectly) Tenant, including, without limitation, any parent corporation
controlling Tenant or any subsidiary that Tenant controls. The term "control,"
as used herein, shall mean the power to direct or cause the direction of the
management and policies of the controlled entity through the ownership of more
than fifty percent (50%) of the voting securities in such controlled entity.
Notwithstanding anything contained in this Article XIV to the contrary, Tenant
expressly covenants and agrees not to enter into any lease, sublease, license,
concession or other agreement for use, occupancy or utilization of the Premises
which provides for rental or other payment for such use, occupancy or
utilization based in whole or in part on the net income or profits derived by
any person from the property leased, used, occupied or utilized (other than an
amount based on a fixed percentage or percentages of receipts or sales), and
that any such purported lease, sublease, license, concession or other agreement
shall be absolutely void and ineffective as a conveyance of any right or
interest in the possession, use, occupancy or utilization of any part of the
Premises.

        14.2 NOTICE TO LANDLORD. If Tenant desires to assign this Lease or any
interest herein, or to sublet all or any part of the Premises, then at least
fifteen (15) days but not more than one hundred eighty (180) days prior to the
effective date of the proposed assignment or subletting, Tenant shall submit to
Landlord in connection with Tenant's request for Landlord's consent:

             14.2.1.Statement. A statement containing (a) the name and address
of the proposed assignee or subtenant; (b) such financial information with
respect to the proposed assignee or subtenant as Landlord shall reasonably
require; (c) the type of use proposed for the Premises; and (d) all of the
principal terms of the proposed assignment or subletting; and

             14.2.2.Original Documents. Four (4) originals of the assignment or
sublease on a form approved by Landlord and four (4) originals of the Landlord's
Consent to Sublease or Assignment and Assumption of Lease and Consent.

        14.3 LANDLORD'S RECAPTURE RIGHTS. At any time within fifteen (15)
business days after Landlord's receipt of all (but not less than all) of the
information and documents described in Section 14.02 above, Landlord may, at its
option by written notice to Tenant, elect to: (a) sublease the Premises or the
portion thereof proposed to be sublet by Tenant upon the same terms as those
offered to the proposed subtenant; (b) take an assignment of the Lease upon the
same terms as those offered to the proposed assignee; or (c) terminate the Lease
in its entirety or as to the portion of the Premises proposed to be assigned or
sublet, with a proportionate adjustment in the Rent payable hereunder if the
Lease is terminated as to less than all of the Premises. If Landlord does not
exercise any of the options described in the preceding sentence, then, during
the above-described twenty (20) business day period, Landlord shall either
consent or deny its consent to the proposed assignment or subletting.

        14.4 LANDLORD'S CONSENT; STANDARDS. Landlord's consent to a proposed
assignment or subletting shall not be unreasonably withheld; but, in addition to
any other

<PAGE>   22

grounds for denial, Landlord's consent shall be deemed reasonably withheld if,
in Landlord's good faith judgment: (a) the proposed assignee or subtenant does
not have the financial strength to perform its obligations under this Lease or
any proposed sublease; (b) the business and operations of the proposed assignee
or subtenant are not of comparable quality to the business and operations being
conducted by other tenants in the Building; (c) the proposed assignee or
subtenant intends to use any part of the Premises for a purpose not permitted
under this Lease; (d) either the proposed assignee or subtenant, or any person
which directly or indirectly controls, is controlled by, or is under common
control with the proposed assignee or subtenant occupies space in the Building,
or is negotiating with Landlord to lease space in the Building; (e) the proposed
assignee or subtenant is disreputable; or (f) the use of the Premises or the
Building by the proposed assignee or subtenant would, in Landlord's reasonable
judgment, impact the Building in a negative manner, including but not limited to
significantly increasing the pedestrian traffic in and out of the Building or
requiring any alterations to the Building to comply with applicable laws; (g)
the subject space is not regular in shape with appropriate means of ingress and
egress suitable for normal renting purposes; (h) the transferee is a government
(or agency or instrumentality thereof), or (i) Tenant has failed to cure a
default at the time Tenant requests consent to the proposed Transfer.

        14.5 ADDITIONAL RENT. If Landlord consents to any such assignment or
subletting, seventy-five percent (75%) of the amount by which all sums or other
economic consideration received by Tenant in Connection with such assignment or
subletting, whether denominated as rental or otherwise of standard marketing
expenses consistent with the then current market conditions in the San Francisco
Financial District, exceeds, in the aggregate, the total sum which Tenant is
obligated to pay Landlord under this Lease (prorated to reflect obligations
allocable to less than all of the Premises under a sublease) shall be paid to
Landlord promptly after receipt as additional Rent under the Lease without
affecting or reducing any other obligation of Tenant hereunder.

        14.6 LANDLORD'S COSTS. If Tenant shall Transfer this Lease or all or any
part of the Premises or shall request the consent of Landlord to any Transfer,
Tenant shall pay to Landlord as additional rent Landlord's costs related
thereto, including Landlord's reasonable attorneys' fees and a minimum fee to
Landlord of Five Hundred Dollars ($500.00).

        14.7 CONTINUING LIABILITY OF TENANT. Notwithstanding any Transfer,
Tenant shall remain as fully and primarily liable for the payment of Rent and
for the performance of all other obligations of Tenant contained in this Lease
to the same extent as if the Transfer had not occurred; provided, however, that
any act or omission of any transferee, other than Landlord, that violates the
terms of this Lease shall be deemed a violation of this Lease by Tenant.

        14.8 NON-WAIVER. The consent by Landlord to any Transfer shall not
relieve Tenant, or any person claiming through or by Tenant, terms, of the
obligation to obtain the consent of Landlord, pursuant to this Article XIV, to
any further Transfer. In the event of an assignment or subletting, Landlord may
collect rent from the assignee or the subtenant without waiving any rights
hereunder and collection of the rent from a person other than Tenant shall not
be a waiver of any of Landlord's rights under this Article XIV, an acceptance of
assignee or subtenant as Tenant, or a release of Tenant from the performance of
Tenant's obligations under this Lease. If Tenant shall default under this Lease
and fail to cure within the time permitted, Landlord is irrevocably authorized,
as Tenant's agent and attorney-in-fact, to direct any transferee to make all
payments under or in connection with the Transfer directly to Landlord (which
Landlord shall apply towards Tenant's obligations under this Lease) until such
default is cured.

                        ARTICLE XV - DEFAULT AND REMEDIES

        15.1 EVENTS OF DEFAULT BY TENANT. The occurrence of any of the following
shall constitute a material default and breach of this Lease by Tenant:

             15.1.1.Failure to Pay Rent. The failure by Tenant to pay Base Rent
or make any other payment required to be made by Tenant hereunder as and when
due.

             15.1.2.Abandonment. The abandonment of the Premises by Tenant or
the vacation of the Premises by Tenant.

<PAGE>   23

             15.1.3.Failure to Perform. The failure by Tenant to observe or
perform any other provision of this Lease to be observed or performed by Tenant,
other than those described in Sections 15.1.1 and 15.1.2 above, if such failure
continues for ten (10) days after written notice thereof by Landlord to Tenant;
provided, however, that if the nature of the default is such that it cannot be
cured within the ten (10) day period, no default shall exist if Tenant commences
the curing of the default within the ten (10) day period and thereafter
diligently prosecutes the same to completion. The ten (10) day notice described
herein shall be in lieu of, and not in addition to, any notice required under
Section 1161 of the California Code of Civil Procedure or any other law now or
hereafter in effect requiring that notice of default be given prior to the
commencement of an unlawful detainer or other legal proceeding.

             15.1.4.Bankruptcy. The making by Tenant or its Guarantor of any
general assignment for the benefit of creditors, the filing by or against Tenant
or its Guarantor of a petition under any federal or state bankruptcy or
insolvency laws (unless, in the case of a petition filed against Tenant or its
Guarantor the same is dismissed within thirty (30) days after filing); the
appointment of a trustee or receiver to take possession of substantially all of
Tenant's assets at the Premises or Tenant's interest in this Lease or the
Premises, when possession is not restored to Tenant within thirty (30) days; or
the attachment, execution or other seizure of substantially all of Tenant's
assets located at the Premises or Tenant's interest in this Lease or the
Premises, if such seizure is not discharged within thirty (30) days.

             15.1.5.Misstatement. Any material misrepresentation herein, or
material misrepresentation or omission in any financial statements or other
materials provided by Tenant or any Guarantor in connection with negotiating or
entering into this Lease or in connection with any Transfer under Section 14.1.

        15.2 LANDLORD'S RIGHT TO TERMINATE UPON TENANT DEFAULT. In the event of
any default by Tenant as provided in Section 15.1 above, Landlord shall have the
right to terminate this Lease and recover possession of the Premises by giving
written notice to Tenant of Landlord's election to terminate this Lease, in
which event Landlord shall be entitled to receive from Tenant: (a) the worth at
the time of award of any unpaid Rent which had been earned at the time of such
on award; plus (b) the worth at the time of award of the amount by which the
unpaid Rent which would have been earned after termination until the time of
award exceeds the amount of such rental loss Tenant proves could have been
reasonably avoided; plus (c) the worth at the time of award of the amount by
which the unpaid Rent for the balance of the term after the time of award
exceeds the amount of such rental loss that Tenant proves could be reasonably
avoided; plus (d) any other amount necessary to compensate Landlord for all the
detriment proximately caused by Tenant's failure to perform its obligations
under this Lease or which in the ordinary course of things would be likely to
result therefrom; and (e) at Landlord's election, such other amounts in addition
to or in lieu of the foregoing as may be permitted from time to time by
applicable law. As used in subsections (a) and (b) above, "worth at the time of
award" shall be computed by allowing interest on such amounts at the then
highest lawful rate of interest, but in no event to exceed one percent (1%) per
annum plus the rate established by the Federal Reserve Bank of San Francisco on
advances made to banks under Sections 13 and 13a of the Reserve Act ("discount
rate") prevailing at the time of award. As used in subsection (c) above, "worth
at the time of award" shall be computed by discounting such amount by (x) the
discount rate of the Federal Reserve Bank of San Francisco prevailing at the
time of award plus (y) one percent (1%).

        15.3 MITIGATION OF DAMAGES. If Landlord terminates this Lease or
Tenant's right to possession of the Premises, Landlord shall have no obligation
to mitigate Landlord's damages except to the extent required by applicable law.
If Landlord has not terminated this Lease or Tenant's right to possession of the
Premises, Landlord shall have no obligation to mitigate under any circumstances
and may permit the Premises to remain vacant or abandoned. If Landlord is
required to mitigate damages as provided herein: (a) Landlord shall be required
only to use reasonable efforts to mitigate, which shall not exceed such efforts
as Landlord generally uses to lease other space in the Building, (b) Landlord
will not be deemed to have failed to mitigate if Landlord or its affiliates
lease any other portions of the Building or other projects owned by Landlord or
its affiliates in the same geographic area, before reletting the Premises or any
portion of the Premises, and (c) any failure to mitigate as described herein
with respect to any period of time shall only reduce the Rent and other amounts
to which Landlord is entitled hereunder by the reasonable rental value of the
Premises during such period. In recognition that the value of the Building is
dependent on the rental rates and terms of leases

<PAGE>   24

therein, Landlord's rejection of a prospective replacement tenant based on an
offer of rentals below Landlord's published rates for new leases of comparable
space at the Building at the time in question, or at Landlord's option, below
the rates provided in this Lease, or containing terms less favorable than those
contained herein, shall not give rise to a claim by Tenant that Landlord failed
to mitigate Landlord's damages.

        15.4 LANDLORD'S RIGHT TO CONTINUE LEASE UPON TENANT DEFAULT. In the
event of a default of this Lease by Tenant, and if Landlord does not elect to
terminate this Lease as provided in Section 15.2 above, Landlord may, from time
to time, without terminating this Lease, enforce all of its rights and remedies
under this Lease or at law or in equity. Without limiting the foregoing,
Landlord has the remedy described in California Civil Code Section 1951.4
(Landlord may continue this Lease in effect after Tenant's default and recover
Rent as it becomes due, if Tenant has the right to Transfer, subject only to
reasonable limitations). In the event Landlord re-lets the Premises, to the
fullest extent permitted by law, the proceeds of any reletting shall be applied
first to pay to Landlord all costs and expenses of such reletting (including
without limitation, costs and expenses of retaking or repossessing the Premises,
removing persons and property therefrom, securing new tenants, including
expenses for redecoration, alterations and other costs in connection with
preparing the Premises for the new tenant, and if Landlord shall maintain and
operate the Premises, the costs thereof) and receivers' fees incurred in
connection with the appointment of and performance by a receiver to protect the
Premises and Landlord's interest under this Lease and any necessary or
reasonable alterations; second, to the payment of any indebtedness of Tenant to
Landlord other than Rent due and unpaid hereunder, third, to the payment of Rent
due and unpaid hereunder; and the residue, if any, shall be held by Landlord and
applied in payment of other or future obligations of Tenant to Landlord as the
same may become due and payable, and Tenant shall not be entitled to receive any
portion of such revenue.

        15.5 RIGHT OF LANDLORD TO PERFORM. All covenants and agreements to be
performed by Tenant under this Lease shall be performed by Tenant at Tenants
sole cost and expense. If Tenant shall fail to pay any sum of money, other than
Rent, required to be paid by it hereunder or shall fail to perform any other act
on its part to be performed hereunder, Landlord may, but shall not be obligated
to, make any payment or perform any such other act on Tenant's part to be made
or performed, without waiving or releasing Tenant of its obligations under this
Lease. Any sums so paid by Landlord and all necessary incidental costs, together
with interest thereon at the lesser of the maximum rate permitted by law if any
or twelve percent (12%) per annum from the date of such payment, shall be
payable to Landlord as additional rent on demand and Landlord shall have the
same rights and remedies in the event of nonpayment as in the case of default by
Tenant in the payment of Rent.

        15.6 DEFAULT UNDER OTHER LEASES. If the term of any lease, other than
this Lease, heretofore or hereafter made by Tenant for any office space in the
Building shall be terminated or terminable after the making of this Lease
because of any default by Tenant under such other lease, such fact shall empower
Landlord, at Landlord's sole option, to terminate this Lease by notice to Tenant
or to exercise any of the rights or remedies set forth in Section 15.2.

        15.7 NON-WAIVER. Nothing in this Article shall be deemed to affect
Landlord's rights to indemnification for liability or liabilities arising prior
to termination of this Lease or Tenant's right to possession for personal injury
or property damages under the indemnification clause or clauses contained in
this Lease. No acceptance by Landlord of a lesser sum than the Rent then due
shall be deemed to be other than on account of the earliest installment of such
rent due, nor shall any endorsement or statement on any check or any letter
accompanying any check or payment as rent be deemed an accord and satisfaction,
and Landlord may accept such check or payment without prejudice to Landlord's
right to recover the balance of such installment or pursue any other remedy in
the Lease provided. The delivery of keys to any employee of Landlord or to
Landlord's agent or any employee thereof shall not operate as a termination of
this Lease or a surrender of the Premises.

        15.8 CUMULATIVE REMEDIES. The specific remedies to which Landlord may
resort under the terms of the Lease are cumulative and are not intended to be
exclusive of any other remedies or means of redress to winch it may be lawfully
entitled in case of any breach or threatened breach by Tenant of any provisions
of the Lease. In addition to the other remedies provided in the Lease, Landlord
shall be entitled to a restraint by injunction of the violation or

<PAGE>   25

attempted or threatened violation of any of the covenants, conditions or
provisions of the Lease or to a decree compelling specific performance of any
such covenants, conditions or provisions.

        15.9 DEFAULT BY LANDLORD. Landlord's failure to perform or observe any
of its obligations under this Lease shall constitute a default by Landlord under
this Lease only if such failure shall continue for a period of thirty (30) days
(or the additional time, if any, which is reasonably necessary to promptly and
diligently cure the failure) after Landlord receives written notice from Tenant
specifying the default. The notice shall give in reasonable detail the nature
and extent of the failure and shall identify the Lease provision(s) containing
the obligation(s). If Landlord shall default in the performance of any of its
obligations under this Lease (after notice and opportunity to cure as provided
herein), Tenant may pursue any remedies available to it under the law and this
Lease, except that in no event shall Landlord be liable for punitive damages,
lost profits, business interruption, speculative, consequential or other such
damages. In recognition that Landlord must receive timely payments of Rent and
operate the Building, Tenant shall have no right of self-help to perform repairs
or any other obligation of Landlord, and shall have no right to withhold,
set-off, or abate Rent, except as specifically set forth in this Lease.

                 ARTICLE XVI - ATTORNEYS' FEES; INDEMNIFICATION

        16.1 ATTORNEYS' FEES. If either Landlord or Tenant shall commence any
action or other proceeding against the other arising out of, or relating to,
this Lease or the Premises, the prevailing party shall be entitled to recover
from the losing party, in addition to any other relief, its actual attorneys'
fees irrespective of whether or not the action or other proceeding is prosecuted
to judgment and irrespective of any court schedule of reasonable attorneys'
fees. In addition, Tenant shall reimburse Landlord, upon demand, for all
reasonable attorneys' fees incurred in collecting Rent or otherwise seeking
interpretation of this Lease or enforcement against Tenant, its sublessees and
assigns, of Tenants obligations under this Lease.

        16.2 INDEMNIFICATION. Should Landlord be made a party to any litigation
instituted by Tenant against a party other than Landlord, or by a third party
against Tenant, Tenant shall indemnify, hold harmless and defend Landlord from
any and all loss, cost, liability, damage or expense incurred by Landlord,
including attorneys' fees, in connection with the litigation.

                   ARTICLE XVII - SUBORDINATION AND ATTORNMENT

        17.1 SUBORDINATION. This Lease, and the rights of Tenant hereunder, are
and shall be subject and subordinate to the interests of (i) all present and
future ground leases and master leases of all or any part of the Building; (ii)
present and future mortgages and deeds of trust encumbering all or any part of
the Building; (iii) all past and future advances made under any such mortgages
or deeds of trust; and (iv) all renewals, modifications, replacements and
extensions of any such ground leases, master leases, mortgages and deeds of
trust; provided, however, that any lessor under any such ground lease or master
lease or any mortgagee or beneficiary under any such mortgage or deed of trust
(any such lessor, mortgagee or beneficiary is hereinafter referred to as a
"Mortgagee") shall have the right to elect, by written notice given to Tenant,
to have this Lease made superior in whole or in part to any such ground lease,
master lease, mortgage or deed of trust (or subject and subordinate to such
ground lease, master lease, mortgage or deed of trust but superior to any junior
mortgage or junior deed of trust). Upon demand, Tenant shall execute,
acknowledge and deliver any instruments reasonably requested by Landlord or any
such Mortgagee to effect the purposes of this Section 17.1. Such instruments may
contain, among other things, provisions to the effect that such Mortgagee
(hereafter, for the purposes of this Section 17.1, a "Successor Landlord") shall
(a) not be liable for any act or omission of Landlord or its predecessors, if
any, prior to the date of such Successor Landlord's succession to Landlord's
interest under this Lease; (b) not be subject to any offsets or defenses which
Tenant might have been able to assert against Landlord or its predecessors, if
any, prior to the date of such Successor Landlord's succession to Landlord's
interest under this Lease; (c) not be liable for the return of any security
deposit under the Lease unless the same shall have actually been deposited with
such Successor Landlord; (d) be entitled to receive notice of any Landlord
default under this Lease plus a reasonable opportunity to cure such default
prior to Tenant having any right or ability to terminate this Lease as a result
of such Landlord default; (e) not be bound by any rent or additional rent which
Tenant might have paid for more than the current month to Landlord; (f) not be
bound by any amendment or modification of the Lease or

<PAGE>   26

any cancellation of the same made without Successor Landlord's prior written
consent; (g) not be bound by any obligation to make any payment to Tenant which
was required to be made prior to the time such Successor Landlord succeeded to
Landlord's interest, and (h) not be bound by any obligation under the Lease to
perform any work or to make any improvements to the demised Premises. Any
obligations of any Successor Landlord under its respective lease shall be
non-recourse as to any assets of such Successor Landlord other than its interest
in the Building and its related improvements. Not withstanding the foregoing,
Tenant's Subordination shall only be effective as to the extent that the future
Mortgagee agrees that this Lease shall survive the termination of the
Mortgagee's interest by lapse of time, foreclosure or otherwise so long as
Tenant is not in default under this Lease.

        17.2 ATTORNMENT. If the interests of Landlord under the Lease shall be
transferred to any superior Mortgagee or Successor Landlord or other purchaser
or person taking title to the Building by reason of the termination of any
superior lease or the foreclosure of any superior mortgage or deed of trust,
Tenant shall be bound to such Successor Landlord under all of the terms,
covenants and conditions of the Lease for the balance of the term thereof
remaining and any extensions or renewals thereof which may be effected in
accordance with any option therefor in the Lease, with the same force and effect
as if Successor Landlord were the landlord under the Lease, and Tenant shall
attorn to and recognize as Tenant's landlord under this Lease such Successor
Landlord, as its landlord, said attornment to be effective and self-operative
without the execution of any further instruments upon Successor Landlord's
succeeding to the interest of Landlord under the Lease. Tenant acknowledges that
Landlord is (a) the assignee of the lessor's interest in that certain Ground
Lease dated June 11, 1963 ("Existing Ground Lease") for the land underlying the
Building, and (b) the assignee of the lessee's interest in the Ground Lease.
Upon expiration or termination of the Existing Ground Lease, Tenant will attorn
to and continue to recognize Landlord as the landlord under this Lease. Tenant
shall, upon demand, execute any documents reasonably requested by any such
person to evidence the adornment described in this Section 17.2. Concurrently,
upon written request from Tenant, and provided Tenant is not in default under
this Lease, Landlord agrees to use diligent, commercially reasonable efforts to
obtain a Non-Disturbance Agreement from the Successor Landlord. Such
Non-Disturbance Agreement may be embodied in the Mortgagee's customary form of
Subordination and Non-Disturbance Agreement. If, after exerting diligent,
commercially reasonable efforts, Landlord is unable to obtain a Non-Disturbance
Agreement from any such Mortgagee, Landlord shall have no further obligation to
Tenant with respect thereto.

        17.3 MORTGAGEE PROTECTION. Tenant agrees to give any Mortgagee, by
registered or certified mail, a copy of any notice of default served upon
Landlord by Tenant, provided that prior to such notice Tenant has been notified
in writing (by way of service on Tenant of a copy of Assignment of Rents and
Leases, or otherwise) of the address of such Mortgagee (hereafter the "Notified
Party"). Tenant further agrees that if Landlord shall have failed to cure such
default within twenty (20) days after such notice to Landlord (or if such
default cannot be cured or corrected within that time, then such additional time
as may be necessary if Landlord has commenced within such twenty (20) days and
is diligently pursuing the remedies or steps necessary to cure or correct such
default), then the Notified Party shall have an additional thirty (30) days
within which to cure or correct such default (or if such default cannot be cured
or corrected within that time, then such additional time as may be necessary if
the Notified Party has commenced within such thirty (30) days and is diligently
pursuing the remedies or steps necessary to cure or correct such default). Until
the time allowed, as aforesaid, for the Notified Party to cure such default has
expired without cure, Tenant shall have no right to, and shall not, terminate
this Lease on account of Landlord's default.

                          ARTICLE XVIII - MISCELLANEOUS

        18.1 QUIET ENJOYMENT. Provided that Tenant performs all of its
obligations hereunder, Tenant shall have and peaceably enjoy the Premises during
the Lease Term free of claims by or through Landlord, subject to all of the
terms and conditions contained in this Lease.

        18.2 RULES AND REGULATIONS. The Rules and Regulations attached hereto as
Exhibit C are hereby incorporated by reference herein and made a part hereof.
Tenant shall abide by, and faithfully observe and comply with the Rules and
Regulations and any reasonable and non-discriminatory amendments, modifications
and/or additions thereto as may hereafter be adopted and published by written
notice to tenants by Landlord for the safety, care, security, good order and/or
cleanliness of the Premises and/or the Building. Landlord shall not be liable

<PAGE>   27

to Tenant for any violation of such rules and regulations by any other tenant or
occupant of the Building.

        18.3 ESTOPPEL CERTIFICATES. Tenant agrees at any time and from time to
time, upon not less than ten (10) business days prior written notice from
Landlord, to execute, acknowledge and deliver to Landlord a statement in writing
addressed and certifying to Landlord, to any current or prospective Mortgagee or
any assignee thereof, to any prospective purchaser of the land, improvements or
both comprising the Building, and to any other party designated by Landlord,
that this Lease is unmodified and in full force and effect (or if there have
been modifications, that the same is in full force and effect as modified and
stating the modifications); that Tenant has accepted possession of the Premises,
which are acceptable in all respects, and that any improvements required by the
terms of this Lease to be made by Landlord have been completed to the
satisfaction of Tenant; that Tenant is in full occupancy of the Premises; that
no rent has been paid more than thirty (30) days in advance; that the first
month's Base Rent has been paid; that Tenant is entitled to no free rent or
other concessions except as stated in this Lease; that Tenant has not been
notified of any previous assignment of Landlord's or any predecessor landlord's
interest under this Lease; the dates to which Base Rent, additional rental and
other charges have been paid; that Tenant, as of the date of such certificate,
has no charge, lien or claim of setoff under this Lease or otherwise against
Base Rent, additional rental or other charges due or to become due under this
Lease; that Landlord is not in default in performance of any covenant, agreement
or condition contained in this Lease; or any other matter relating to this Lease
or the Premises or, if so, specifying each such default. If there is a Guaranty
under this Lease, said Guarantor shall confirm the validity of the Guaranty by
joining in the execution of the Estoppel Certificate or other documents so
requested by Landlord or Mortgagee. In addition, in the event that such
certificate is being given to any Mortgagee, such statement may contain any
other provisions customarily required by such Mortgagee including, without
limitations an agreement on the part of Tenant to furnish to such Mortgagee,
written notice of any Landlord default and a reasonable opportunity for such
Mortgagee to cure such default prior to Tenant being able to terminate this
Lease. Any such statement delivered pursuant to this Section may be relied upon
by Landlord or any Mortgagee, or prospective purchaser to whom it is addressed
and such statement, if required by its addressee, may so specifically state. If
Tenant does not execute, acknowledge and deliver to Landlord the statement as
and when required herein, Landlord is hereby granted an irrevocable power of
attorney, coupled with an interest, to execute such statement on Tenant's
behalf, which statement shall be binding on Tenant to the same extent as if
executed by Tenant.

        18.4 ENTRY BY LANDLORD. Landlord may enter the Premises at all
reasonable times to: inspect the same; exhibit the same to prospective
purchasers, Mortgagees or tenants; determine whether Tenant is complying with
all of its obligations under this Lease; supply janitorial and other services to
be provided by Landlord to Tenant under this Lease; post notices of
non-responsibility; and make repairs or improvements in or to the Building or
the Premises; provided, however, that all such work shall be done as promptly as
reasonably possible and so as to cause as little interference to Tenant as
reasonably possible. Tenant hereby waives any claim for damages for any injury
or inconvenience to, or interference with, Tenant's business, any loss of
occupancy or quiet enjoyment of the Premises or any other loss occasioned by
such entry. Landlord at all times shall have and retain a key with which to
unlock all of the doors in, on or about the Premises (excluding Tenant's vaults,
safes and similar areas designated by Tenant in writing in advance), and
Landlord shall have the right to use any and all means by which Landlord may
deem proper to open such doors to obtain entry to the Premises, and any entry to
the Premises obtained by Landlord by any such means, or otherwise, shall not
under any circumstances be or construed to be a forcible or unlawful entry into
or a detainer of the Premises or an eviction, actual or constructive, of Tenant
from any part of the Premises. Such entry by Landlord shall not act as a
termination of Tenant's duties under this Lease. If Landlord shall be required
to obtain entry by means other than a key provided by Tenant, the cost of such
entry shall be payable by Tenant to Landlord as additional rent.

        18.5 LANDLORD'S LEASE UNDERTAKINGS. Notwithstanding anything to the
contrary contained in this Lease or in any exhibits, Riders or addenda hereto
attached (collectively the "Lease Documents"), it is expressly understood and
agreed by and between the parties hereto that: (a) the recourse of Tenant or its
successors or assigns against Landlord with respect to the alleged breach by or
on the part of Landlord of any representation, warranty, covenant, undertaking
or agreement contained in any of the Lease Documents or otherwise arising out of
Tenant's use of the Premises or the Building (collectively, "Landlord's Lease

<PAGE>   28

Undertaking") shall extend only to Landlord's interest in the real estate of
which the Premises demised under the Lease Documents are a part ("Landlord's
Real Estate") and not to any other assets of Landlord or its beneficiaries; and
(b) no personal liability or personal responsibility of any sort with respect to
any of Landlord's Lease Undertakings or any alleged breach thereof is assumed
by, or shall at any time be asserted or enforceable against, Landlord, OTR," an
Ohio general partnership, Seagate Properties, Inc., Seagate Realty Advisors, or
against any of their respective directors, officers, employees, agents,
constituent partners, beneficiaries, trustees or representatives. Tenant
acknowledges that this Lease is executed by certain general partners of OTR
and/or Seagate Realty Advisors, not individually but solely on behalf of, and as
the authorized nominee and agent for, the State Teachers Retirement Board of
Ohio, and Tenant and all persons dealing with Landlord waive any right to bring
a cause of action against the individuals executing this Lease on behalf of
Landlord and must look solely to the assets of State Teachers Retirement Board
of Ohio for the enforcement of any claim against Landlord.

        18.6 TRANSFER OF LANDLORD'S INTEREST. In the event of any transfer of
Landlord's interest in the Building, Landlord shall be automatically freed and
relieved from all applicable liability with respect to performance of any
covenant or obligation on the part of Landlord under this Lease occurring after
the date of such transfer, provided any deposits or advance rents held by
Landlord are turned over to the grantee and said grantee expressly assumes,
subject to the limitations of this Lease, all the terms, covenants and
conditions of this Lease to be performed on the part of Landlord, it being
intended hereby that the covenants and obligations contained in this Lease on
the part of Landlord shall, subject to all the provisions of this Lease, be
binding on Landlord, its successors and assigns, only during their respective
periods of ownership.

        18.7 HOLDOVER. If Tenant holds possession of the Premises after the
expiration or termination of the Lease Term, by lapse of time or otherwise,
Tenant shall become a tenant at sufferance upon all of the terms contained
herein, except as to Lease Term and Rent. During such holdover period, Tenant
shall pay to Landlord a monthly rental equivalent to one hundred fifty percent
(150%) of the Rent payable by Tenant to Landlord with respect to the last month
of the Lease Term and Rent for the first sixty (60) days after expiration or
termination of the Lease; after the first sixty (60) day period after
expiration, Tenant shall pay to Landlord a monthly rental equivalent to two
hundred percent (200%) of the Rent payable by Tenant to Landlord with respect to
the last month of the Lease Term. The monthly rent payable for such holdover
period shall in no event be construed as a penalty or as liquidated damages for
such retention of possession. Without limiting the foregoing Tenant hereby
agrees to indemnify, defend and hold harmless Landlord, its beneficiary, and
their respective agents, contractors and employees, from and against any and all
claims, liabilities, actions, losses, damages (including without limitation,
direct, indirect, incidental and consequential) and expenses (including, without
limitation, court costs and reasonable attorneys' fees) asserted against or
sustained by any such party and arising from or by reason of such retention of
possession, which obligations shall survive the expiration or termination of the
Lease Term.

        18.8 NOTICES. All notices which Landlord or Tenant may be required, or
may desire, to serve on the other may be served, as an alternative to personal
service, by mailing the same by registered or certified mail, postage prepaid,
addressed to Landlord at the address for Landlord get forth in Section 1.13
above and to Tenant at the address for Tenant set forth in Section 1.14 above,
or, from and after the Commencement Date, to Tenant at the Premises whether or
not Tenant has departed from, abandoned or vacated the Premises, or addressed to
such other address or addresses as either Landlord or Tenant may from time to
time designate to the other in writing. Any notice shall be deemed to have been
served at the time the same was posted.

        18.9 BROKERS. The parties recognize as the broker(s) who procured this
Lease the firm(s) specified in Section 1.15 and agree that Landlord shall be
solely responsible for the payment of any brokerage commissions to said
broker(s), and that Tenant shall have no responsibility therefor unless written
provision to the contrary has been made a part of this Lease. If Tenant has
dealt with any other person or real estate broker in respect to leasing,
subleasing or renting space in the Building, Tenant shall be solely responsible
for the payment of any fee due said person or firm and Tenant shall protect,
indemnify, hold harmless and defend Landlord from any liability in respect
thereto.

<PAGE>   29

        18.10 COMMUNICATIONS AND COMPUTER LINES. Tenant may, in a manner
consistent with the provisions and requirements of this Lease, install,
maintain, replace, remove or use any communications or computer wires, cables
and related devices (collectively the "Lines") at the Building in or serving the
Premises, provided: (a) Tenant shall obtain Landlord's prior written consent,
which consent may be conditioned as required by Landlord, (b) if Tenant at any
time uses any equipment that may create an electromagnetic field exceeding the
normal insulation ratings of ordinary twisted pair riser cable or cause
radiation higher than normal background radiation, the Lines therefor (including
riser cables) shall be appropriately insulated to prevent such excessive
electromagnetic fields or radiation, and (c) Tenant shall pay all costs in
connection therewith. Landlord reserves the right to require that Tenant remove
any Lines which are installed in violation of these provisions.

             18.10.1. NEW LINES. Landlord may (but shall not have the obligation
to): (a) install new Lines at the Property, and (b) create additional space for
Lines at the Property, and adopt reasonable and uniform rules and regulations
with respect to the Lines.

             18.10.2. LINE PROBLEMS. Notwithstanding anything to the contrary
contained in this Lease, Landlord reserves the right to require that Tenant
remove any or all Lines installed by or for Tenant within or serving the
Premises. Tenant shall not, without the prior written consent of Landlord in
each instance, grant to any third party a security interest or lien in or on the
Lines, and any such security interest or lien granted without Landlord's written
consent shall be null and void. Except to the extent arising from the
intentional or negligent acts of Landlord or Landlord's agents or employees,
Landlord shall have no liability for damages arising from, and Landlord does not
warrant that Tenant's use of any Lines will be free from the following,
(collectively called "Line Problems"): (a) any eavesdropping or wire-tapping by
unauthorized parties, (b) any failure of any Lines to satisfy Tenants
requirements, or (c) any shortages, failures, variations, interruptions,
disconnections, loss or damage caused by the installation, maintenance,
replacement, use or removal of Lines by or for other tenants or occupants at the
Property. Under no circumstances shall any Line Problems be deemed an actual or
constructive eviction of Tenant, render Landlord liable to Tenant for abatement
of Rent; or relieve Tenant from performance of Tenant's obligations under this
Lease. Landlord in no event shall be liable for damages by reason of loss of
profits, business interruption or other consequential damage arising from any
Line Problems.

        18.11 ENTIRE AGREEMENT. This Lease contains all of the agreements and
understandings relating to the leasing of the Premises and the obligations of
Landlord and Tenant in connection with such leasing. Landlord has not made, and
Tenant is not relying upon, any warranties, or representations, promises or
statements made by Landlord or any agent of Landlord, except as expressly set
forth herein. This Lease supersedes any and all prior agreements and
understandings between Landlord and Tenant and alone expresses the agreement of
the parties.

        18.12 AMENDMENTS. This Lease shall not be amended, changed or modified
in any way unless in writing executed by Landlord and Tenant. Landlord shall not
have waived or released any of its rights hereunder unless in writing and
executed by Landlord.

        18.13 SUCCESSORS. Subject to the limitations expressly provided herein,
this Lease and the obligations of Landlord and Tenant contained herein shall
bind and benefit the successors and assigns of the parties hereto.

        18.14 FORCE MAJEURE. Landlord shall incur no liability to Tenant with
respect to, and shall not be responsible for any failure to perform, any of
Landlord's obligations hereunder if such failure is caused by any reason beyond
the control of Landlord including, but not limited to, strike, labor trouble,
governmental rule, regulations, ordinance, statute or interpretation, or by
fire, earthquake, civil commotion, or failure or disruption of utility services.
The amount of time for Landlord to perform any of Landlord's obligations shall
be extended by the amount of time Landlord is delayed in performing such
obligation by reason of any force majeure occurrence whether similar to or
different from the foregoing types of occurrences.

        18.15 SURVIVAL OF OBLIGATIONS. Any obligations of Tenant accruing prior
to the expiration of the Lease shall survive the expiration or earlier
termination of the Lease, and Tenant shall promptly perform all such obligations
whether or not this Lease has expired or been terminated.

<PAGE>   30

        18.16 LIGHT AND AIR. No diminution or shutting off of any light, air or
view by any structure now or hereafter erected shall in any manner affect this
Lease or the obligations of Tenant hereunder, or increase any of the obligations
of Landlord hereunder.

        18.17 GOVERNING LAW. This Lease shall be governed by, and construed in
accordance with, the laws of the State of California.

        18.18 SEVERABILITY. In the event any provision of this Lease is found to
be unenforceable, the remainder of this Lease shall not be affected, and any
provision found to be invalid shall be enforceable to the extent permitted by
law. The parties agree that in the event two different interpretations may be
given to any provision hereunder, one of which will render the provision
unenforceable, and one of which will render the provision enforceable, the
interpretation rendering the provision enforceable shall be adopted.

        18.19 CAPTIONS. All captions, headings, titles, numerical references and
computer highlighting are for convenience only and shall have no effect on the
interpretation of this Lease.

        18.20 INTERPRETATION. Tenant acknowledges that it has read and reviewed
this Lease and that it has had the opportunity to confer with counsel in the
negotiation of this Lease. Accordingly, this Lease shall be construed neither
for nor against Landlord or Tenant, but shall be given a fair and reasonable
interpretation in accordance with the plain meaning of its terms and the intent
of the parties.

        18.21 INDEPENDENT COVENANTS. Each covenant, agreement, obligation or
other provision of this Lease to be performed by Tenant are separate and
independent covenants of Tenant, and not dependent on any other provision of the
Lease.

        18.22 NUMBER AND GENDER. All terms and words used in this Lease,
regardless of the number or gender in which they are used, shall be deemed to
include the appropriate number and gender, as the context may require.

        18.23 TIME IS OF THE ESSENCE. Time is of the essence of this Lease and
the performance of all obligations hereunder.

        18.24 JOINT AND SEVERAL LIABILITY. If Tenant comprises more than one
person or entity, or if this Lease is guaranteed by any party, all such persons
shall be jointly and severally liable for payment of rents and the performance
of Tenant's obligations hereunder.

        18.25 EXHIBITS. Exhibits A (Floor Plan), B (Work Letter Agreement), C
(Rules and Regulations), and E (Acceptance Letter), and are incorporated into
this Lease by reference and made a part hereof.

        18.26 OFFER TO LEASE. The submission of this Lease to Tenant or its
broker or other agent, does not constitute an offer to Tenant to lease the
Premises. This Lease shall have no force and effect until (a) it is executed and
delivered by Tenant to Landlord, and (b) it is fully reviewed, executed and
delivered by Landlord to Tenant; provided, however, that upon execution of this
Lease by Tenant and delivery to Landlord, such execution and delivery by Tenant
shall, in consideration of the time and expense incurred by Landlord in
reviewing the Lease and Tenant's credit, constitute an offer by Tenant to Lease
the Premises upon the terms and conditions set forth herein (which offer to
Lease shall be irrevocable for twenty (20) business days following the date of
delivery).

        18.27 NO COUNTERCLAIM; CHOICE OF LAWS. It is mutually agreed that in the
event Landlord commences any summary proceeding for non-payment of Rent, Tenant
will not interpose any counterclaim of whatever nature or description in any
such proceeding. In addition, Tenant hereby submits to local jurisdiction in the
State of California and agrees that any action by Tenant against Landlord shall
be instituted in the State of California and that Landlord shall have personal
jurisdiction over Tenant for any action brought by Landlord against Tenant in
the State of California.

        18.28 RIGHTS RESERVED BY LANDLORD. Landlord reserves the following
rights exercisable without notice (except as otherwise expressly provided to the
contrary in this Lease) and without being deemed an eviction or disturbance of
Tenant's use or possession of the

<PAGE>   31

Premises or giving rise to any claim for set-off or abatement of Rent: (a) to
change the name or street address of the Building; (b) to install, affix and
maintain all signs on the exterior and/or interior of the Building; (c) to
designate and/or approve prior to installation, all types of signs, window
shades, blinds, drapes, awnings or other similar items, and all internal
lighting that may be visible from the exterior of the Premises and,
notwithstanding the provisions of Article IX, the design, arrangement, style,
color and general appearance of the portion of the Premises visible from the
exterior, and contents thereof, including, without limitation, furniture,
fixtures, equipment, art work, wall coverings, carpet and decorations, and all
changes, additions and removals thereto, shall, at all times have the appearance
of premises having the same type of exposure and used for substantially the same
purposes that are generally prevailing in comparable office buildings in the
area; (d) to change the arrangement of entrances, doors, corridors, elevators
and/or stairs in the Building, provided no such change shall materially
adversely affect access to the Premises; (e) to grant any party the exclusive
right to conduct any business or render any service in the Building, provided
such exclusive right shall not operate to prohibit Tenant from using the
Premises for the purposes permitted under this Lease; (f) to prohibit the
placement of vending or dispensing machines of any kind in or about the Premises
other than for use by Tenant's employees; (g) to prohibit the placement of video
or other electronic games in the Premises; (h) to have access for Landlord and
other tenants of the Building to any mail chutes and boxes located in or on the
Premises according to the rules of the United States Post Office and to
discontinue any mail chute business in the Building; (i) to close the Building
after normal business hours, except that Tenant and its employees and invitees
shall be entitled to admission at all times under such rules and regulations as
Landlord prescribes for security purposes; (j) to install, operate and maintain
security systems which monitor, by close circuit television or otherwise, all
persons entering or exiting the Building; (k) to install and maintain pipes,
ducts, conduits, wires and structural elements located in the Premises which
serve other parts or other tenants of the Building; and (l) to retain at all
times master keys or pass keys to the Premises. Any violation of this provision
shall be deemed a material breach of this Lease.

        18.29 ASBESTOS. Tenant acknowledges that it has been expressly disclosed
to Tenant by Landlord's Managing Agent that the Building and the Premises
contain asbestos containing materials ("ACM"). The acknowledgment by Tenant of
the ACM does not in any manner impose any liability or responsibility on Tenant
for removal, treatment, or abatement of such ACM or any responsibility
whatsoever regarding such ACM provided, however, that Tenant shall comply with
all applicable laws and regulations in connection with any work in the Premises
including, but not limited to, work which requires entry into the ceiling.

        18.30 ADR PROCESS. If Landlord and Tenant are unable for any reason to
timely agree on (i) the Prevailing Rental Rate referenced in Section 3.2.1, if
applicable, or (ii) the correction of alleged errors in Landlord's Statement as
provided in Section 4.4. or (iii) the amount of Base Rent to be abated if an
interruption of services or utilities occurs as described in Section 7.2 or an
impairment to the Premises occurs due to Landlord's failure to maintain or
repair as described in Section 8.2 (collectively, "SPECIFIED Disputes"), then
Landlord and Tenant agree that all Specified Disputes shall be resolved pursuant
to the neutral binding alternative dispute resolution process ("ADR PROCESS")
described below. Landlord and Tenant (acting together or individually) shall
submit a notice of a Specified Dispute ("NOTICE OF DISPUTE") to JAMS (defined
below) which Notice sets forth the details of the dispute and requests JAMS to
implement the ADR Process set forth below.

        (A) ADR Process. The Notice of Dispute shall be delivered to the San
Francisco office of Judicial Arbitration and Mediation Service ("JAMS") for
binding resolution pursuant to the ADR Process. The ADR Process shall be
conducted according to the following procedure:

                  (i) The ADR Process shall be conducted in San Francisco,
California.

                  (ii) JAMS shall promptly select a single retired California
Superior Court Judge to be the hearing officer ("HEARING OFFICER"). The Hearing
Officer shall not have any actual or perceived conflict of interest with
Landlord or Tenant, any affiliate or subsidiary or their respective counsel and
absent any conflict, neither Landlord or Tenant shall have the right to object
to the Hearing Officer. The Hearing Officer shall have extensive and recent
civil trial experience and shall not have been primarily a criminal courts judge
during

<PAGE>   32

his/her career. The first hearing day shall be scheduled not later than thirty
(30) calendar days following appointment of the Hearing Officer and the hearing
process shall be concluded within thirty (30) calendar days from commencement.

                  (iii) The Hearing Officer shall preside over the ADR Process,
shall accept relevant evidence, and may (in her/her discretion) hear live
testimony of the parties and their expert and other witnesses, examine and
cross-examine the parties and their witnesses, allow counsel to examine and
cross-examine witnesses, hear arguments of counsel, and otherwise conduct and
control a hearing as if he/she were sitting as a California Superior Court Judge
without a jury. At the conclusion of the hearing, the Hearing Officer shall
orally announce a tentative decision as to the disagreement(s) which form the
basis of the Specified Dispute(s). In announcing the tentative decision and in
rendering the Final Award (defined below), the Hearing Officer shall be required
to follow California law in the interpretation of any document or agreement
(including this Lease), in admitting evidence and in fashioning a remedy. The
Hearing Officer shall not have the power or authority to award any amount in the
nature or character of punitive or exemplary damages, but shall have the power
to issue an award for compensatory damages based on breach or default of the
Lease, shall have the power to issue injunctive or other equitable relief where
appropriate, shall have the power to issue a judgment for unlawful detainer of
the Premises, and shall have the power to issue an award for attorneys' fees and
costs as allowed by this Lease.

                  (iv) Within ten (l0) calendar days following conclusion of the
oral hearing, the Hearing Officer shall prepare and deliver to each of the
parties a written decision, accompanied by a statement of facts, law, underlying
reasons and conclusions necessary to fully explain his/her decision ("FINAL
AWARD"). If the Final Award requires payment by one party of any amount of money
to the other party, the Hearing Officer shall require that payment be made
within thirty (30) calendar days following issuance of the Final Award, and, if
payment is not timely made, the Final Award shall provide the party to whom
payment is due with the right but not the obligation to seek immediate
enforcement of the Final Award by a court of competent jurisdiction.

                  (v) The Final Award shall be binding on each party to the
dispute, shall be admissible in any court of law for any purpose reasonably
related thereto (including, but not limited to, for the purpose of determining
whether or not a breach or default under the Lease has occurred), and either
party may petition the California Superior Court to enter the Final Award as the
final judgement and award of the court and/or to enforce enforcement of a Final
Award.

                  (vi) Each party shall pay one-half of the fees and costs for
JAMS and the Hearing Officer. If advance payment or deposit is required prior to
commencement of the ADR Process, each party to the dispute hereby represents and
warrants that it will timely pay and deposit said amount. The failure to timely
pay any amounts requested by the Hearing Officer or JAMS shall constitute an
immediate and material event of default and if said amounts are not timely paid
following receipt of a five (5) business day notice and demand to pay, the
Hearing Officer shall be required (without the taking of any evidence or
testimony) to issue a Final Award in favor of the party to the dispute timely
paying its fees, on the terms and conditions requested by said party, which
shall be final and binding.

        18.31 MISCELLANEOUS SIGNAGE. Upon move-in, Tenant shall receive from
Landlord at Landlord's cost:

    l)  One suite sign insert which includes insert and one line of verbiage

    2)  One elevator lobby strip

    3)  One main lobby strip for each 750 square feet leased

    4)  Two suite keys and two restroom guest keys

All signage shall be in accordance with Building Standard signage specification
and is subject to Landlord's prior approval. Additional signage and keys may be
purchased through Seagate Properties, Inc.

        IN WITNESS WHEREOF, the parties hereto have executed this lease as of
the date first above written.

<PAGE>   33

LANDLORD:                              TENANT:

OTR, an Ohio general                   CHEMCONNECT, INC., A DELAWARE
partnership, as Nominee of The         CORPORATION
State Teachers Retirement
Board of Ohio, a statutory
organization created by the
laws of Ohio                           By:
                                          --------------------------------------
By: SEAGATE REALTY ADVISORS, A         Its:
    CALIFORNIA GENERAL                     -------------------------------------
    PARTNERSHIP, ITS DULY              Date:
    AUTHORIZED AGENT                        ------------------------------------

By:
   -----------------------------------
Its:
    ----------------------------------
Date:
     ---------------------------------

<PAGE>   34

                                    EXHIBIT A

                             FLOOR PLAN OF PREMISES

This Exhibit A is attached to and made a part of that certain Lease dated
September 20, 1999, by and between OTR, AND OHIO GENERAL PARTNERSHIP, AS NOMINEE
FOR THE STATE TEACHER'S RETIREMENT BOARD OF OHIO, a statutory organization
created by the laws of Ohio, as Landlord, and CHEMCONNECT, INC. a Delaware
corporation as Tenant, in the Building commonly referred to as 44 Montgomery
Street.

                            [Diagram of Leased Space]

                                    EXHIBIT A
<PAGE>   35

                                    EXHIBIT B

                              WORK LETTER AGREEMENT

        This Work Letter Agreement ("Work Letter") is executed simultaneously
with that certain Office Lease (the "Lease") between CHEMCONNECT, INC., a
Delaware corporation as "Tenant", and OTR, an Ohio general partnership, as
Nominee of The State Teachers Retirement Board of Ohio, a statutory organization
created by the laws of Ohio, as "Landlord", relating to demised premises
("Premises") at the building commonly known as 44 MONTGOMERY STREET (the
"Building"), which Premises are more fully identified in the Lease. Capitalized
terms used herein, unless otherwise defined in this Work Letter, shall have the
respective meanings ascribed to them m the Lease.

        For and in consideration of the agreement to lease the Premises and the
mutual covenants contained herein and in the Lease, Landlord and Tenant hereby
agree as follows:

        1. Tenant's Initial Plans; the Work. Tenant desires Landlord to perform
certain leasehold improvement work in the Premises in substantial accordance
with the plan or plans (collectively, the "Initial Plan") which if not attached
hereto as Schedule 1, both Landlord and Tenant shall make a good faith effort to
have a mutually acceptable Initial Plan drawn within fifteen (15) days hereof,
and will then be made an attachment to the Lease. Such work, as shown in the
Initial Plan and as more fully detailed in the Working Drawings (as defined and
described in Paragraph 2 below), shall be hereinafter referred to as the "Work".
Not later than September 15, 1999, Tenant shall furnish to Landlord such
additional plans, drawings, specifications and finish details as Landlord may
reasonably request to enable Landlord's architects and engineers to prepare
mechanical, electrical and plumbing plans and to prepare the Working Drawings,
including a final telephone layout and special electrical connection
requirements, if any. All plans, drawings, specifications and other details
describing the Work which have been or are hereafter furnished by or on behalf
of Tenant shall be subject to Landlord's approval, which Landlord agrees shall
not be unreasonably withheld. Landlord shall not be deemed to have acted
unreasonably if it withholds its approval of any plans, specifications, drawings
or other details or of any Additional Work (as defined in Paragraph 7 below)
because, in Landlord's reasonable opinion, the work, as described in any such
item, or the Additional Work, as the case may be: (a) is likely to adversely
affect Building systems, the structure of the Building or the safety of the
Building and/or its occupants; (b) might impair Landlord's ability to furnish
services to Tenant or other tenants in the Building; (c) would increase the cost
of operating the Building; (d) would violate any governmental laws, rules or
ordinances (or interpretations thereof); (e) contains or uses hazardous or toxic
materials or substances; (f) would adversely affect the appearance of the
Building; (g) might adversely affect another tenant's premises; (h) is
prohibited by any ground lease affecting the Building or any mortgage, trust
deed or other instrument encumbering the Building; or (i) is likely to be
substantially delayed because of unavailability or shortage of labor or
materials necessary to perform such work or the difficulties or unusual nature
of such work. The foregoing reasons, however, shall not be the only reasons for
which Landlord may withhold its approval, whether or not such other reasons are
similar or dissimilar to the foregoing. Neither the approval by Landlord of the
Work or the Initial Plan or any other plans, drawings, specifications or other
items associated with the Work nor Landlord's performance, supervision or
monitoring of the Work shall constitute any warranty by Landlord to Tenant of
the adequacy of the design for Tenant's intended use of the Premises.

        2. Working Drawings. If necessary for the performance of the Work and
not included as part of the Initial Plan attached hereto, Landlord shall prepare
or cause to be prepared final working drawings and specifications for the Work
(the "Working Drawings") based on and consistent with the Initial Plan and the
other plans, drawings, specifications, finish details and other information
furnished by Tenant to Landlord and approved by Landlord pursuant to Paragraph 1
above. So long as the Working Drawings are consistent with the Initial Plan,
Tenant shall approve the Working Drawings within three (3) days after receipt of
same from Landlord by initialing and returning to Landlord each sheet of the
Working Drawings or by executing Landlord's approval form then in use, whichever
method of approval Landlord may designate.

        3. Performance of the Work; Allowance. Except as hereinafter provided to
the contrary, Landlord shall cause the performance of the Work (except as may be
stated or shown otherwise in the Working Drawings) building standard materials,
quantities and

                                    EXHIBIT B
                                       1
<PAGE>   36

procedures then in use by Landlord ("Building Standards"). Landlord shall pay
for a portion of the "Cost of the Work" (as defined below) in an amount not to
exceed $6,000.00 (the "Allowance"), and Tenant shall pay for the entire Cost of
the Work in excess of the Allowance. Tenant shall not be entitled to any credit,
abatement or payment from Landlord in the event that the amount of the Allowance
specified above exceeds the Cost of the Work. For purposes of this Agreement,
the term "Cost of the Work" shall mean and include any and all costs expenses of
the Work, including, without limitation, the cost of the Working Drawings and of
all labor (including overtime) and materials constituting the Work.

        4. Payment. Prior to commencing the Work, Landlord shall submit to
Tenant a written statement of the total Cost of the Work (which shall include
the amount of any overtime projected as necessary to substantially complete the
Work by the Commencement Date specified in the Lease) as then known by Landlord,
and such statement shall indicate the amount, if any, by which the total Cost of
the Work exceeds the Allowance (the "Excess Costs"). Tenant agrees, within three
(3) days after submission to it of such statement, to execute and deliver to
Landlord, in the form then in use by Landlord, an authorization to proceed with
the Work, and Tenant shall also then pay to Landlord an amount equal to the
Excess Costs. No Work shall be commenced until Tenant has fully complied with
the preceding provisions of this Paragraph 4. In the event, and each time, that
any change order by Tenant unknown field condition, delay caused by acts beyond
Landlord's control or other event or circumstance causes the Cost of the Work to
be increased after the time that Landlord delivers to Tenant the aforesaid
initial statement of the Cost of the Work, Landlord shall deliver to Tenant a
revised statement of the total Cost of the Work, indicating the revised
calculation of the Excess Costs, if any. Within three (3) days after submission
to Tenant of any such revised statement, Tenant shall pay to Landlord an amount
equal to the Excess Costs, as shown in such revised statement, less the amounts
previously paid by Tenant to Landlord on account of the Excess Costs, and
Landlord shall not be required to proceed further with the Work until Tenant has
paid such amount. Delays in the performance of the Work resulting from the
failure of Tenant to comply with the provisions of this Paragraph 4 shall be
deemed to be delays caused by Tenant.

        5. Substantial Completion. Landlord shall cause the Work to be
substantially completed on or before the scheduled date of commencement of the
term of the Lease as specified in Section 1.6 of the Lease, subject to delays
caused by strikes, lockouts, boycotts or other labor problems, casualties,
discontinuance of any utility or other service required for performance of the
Work, unavailability or shortages of materials or other problems in obtaining
materials necessary for performance of the Work or any other matter beyond the
control of Landlord (or beyond the control of Landlord's contractors or
subcontractors performing the Work) and also subject to "Tenant Delays" (as
defined and described in Paragraph 6 of this Work Letter). The Work shall be
deemed to be "substantially completed" for all purposes under this Work Letter
and the Lease if and when Landlord's architect issues a written certificate to
Landlord and Tenant, certifying that the Work has been substantially completed
(i.e., completed except for "punchlist" items listed in such architect's
certificate) in substantial compliance with the Working Drawings, or when Tenant
first takes occupancy of the Premises, whichever first occurs. If the Work is
not deemed to be substantially completed on or before the scheduled date of the
commencement of the term of the Lease as specified in Section 1.6 of the Lease,
(a) Landlord agrees to use reasonable efforts to complete the Work as soon as
practicable thereafter, (b) the Lease shall remain in full force and effect, (c)
Landlord shall not be deemed to be in breach or default or the Lease or this
Work Letter as a result thereof and Landlord shall have no liability to Tenant
as a result of any delay in occupancy (whether for damages, abatement of Rent or
otherwise), and (d) except in the event of Tenant Delays, and notwithstanding
anything contained in the Lease to the contrary, the Commencement Date of the
Lease Term as specified in Section 1.6 of the Lease shall be extended to the
date on which the Work is deemed to be substantially completed and the
Expiration Date of the Lease Term as specified in Section 1.7 of the Lease shall
be extended by an equal number of days. At the request of either Landlord or
Tenant in the event of such extensions in the commencement and expiration dates
of the term of the Lease, Tenant and Landlord shall execute and deliver an
amendment to the Lease reflecting such extensions. Landlord agrees to use
reasonable diligence to complete all punchlist work listed in the aforesaid
architect's certificate promptly after substantial completion.

        6. Tenant Delays. There shall be no extension of the scheduled
commencement or expiration date of the term of the Lease (as otherwise
permissibly extended under Paragraph 5 above) if the Work has not been
substantially completed on said scheduled

                                    EXHIBIT B
                                       2
<PAGE>   37

commencement date by reason of any delay attributable to Tenant ("Tenant
Delays"), including without limitation:

             (i) the failure of Tenant to furnish all or any plans, drawings,
specifications, finish details or the other information required under Paragraph
1 above on or before the date stated in Paragraph 1;

             (ii) the failure of Tenant to grant approval of the Working
Drawings within the time required under Paragraph 2 above;

             (iii) the failure of Tenant to comply with the requirements of
Paragraph 4 above;

             (iv) Tenant's requirements for special work or materials, finishes,
or installations other than the Building Standards or Tenant's requirement for
special construction staging or phasing;

             (v) the performance of any Additional Work (as defined in Paragraph
7 below) requested by Tenant or the performance of any work in the Premises by
any person, firm or corporation employed by or on behalf of Tenant, or any
failure to complete or delay in completion of such work; or

             (vi) any other act or omission of Tenant that causes a delay.

        7. Additional Work. Upon Tenant's request and submission by Tenant (at
Tenant's sole cost and expense) of the necessary information and/or plans and
specifications for work other than the Work described in the Working Drawings
("Additional Work") and the approval by Landlord of such Additional Work, which
approval Landlord agrees shall not be unreasonably withheld, Landlord shall
perform such Additional Work, at Tenant's sole cost and expense, subject,
however, to the following provisions of this Paragraph 7. Prior to commencing
any Additional Work requested by Tenant, Landlord shall submit to Tenant a
written statement of the cost of such Additional Work, which cost shall include
a fee payable to Landlord in the amount of 15% of the total cost of such
Additional Work as compensation to Landlord for monitoring the Additional Work
and for administration, overhead and field supervision associated with the
Additional Work. (such fee being hereinafter referred to as "Landlord's
Additional Compensation"), and, concurrently with such statement of cost,
Landlord shall also submit to Tenant a proposed tenant extra order (the "TEO")
for the Additional Work in the standard form then in use by Landlord. Tenant
shall execute and deliver to Landlord such TEO and shall pay to Landlord the
entire cost of the Additional Work, including Landlord's Additional Compensation
(as reflected in Landlord's statement of such cost), within five (5) days after
Landlord's submission of such statement and TEO to Tenant. If Tenant fails to
execute or deliver such TEO or pay the entire cost of such Additional Work
within such 5-day period, then Landlord shall not be obligated to do any of the
Additional Work and may proceed to do only the Work, as specified in the Working
Drawings.

        8. Charges and Fees. Tenant shall pay Landlord a construction
management/supervisory fee in an amount equal to twelve percent (12%) of the
direct cost of the materials and labor for the Work (and all change orders with
respect thereto) to defray Landlord's administrative and overhead expenses
incurred to review the Plans and coordinate with architects, engineers, general
contractors and, if necessary, the Tenant's on-site project manager regarding
the staging and progression of the Work.

        9. Tenant Access. Landlord, in Landlord's reasonable discretion and upon
request by Tenant, may grant to Tenant a license to have access to the Premises
prior to the date designated in the Lease for the commencement of the term of
the Lease to allow Tenant to do other work required by Tenant to make the
Premises ready for Tenant's use and occupancy (the "Tenant's Pre-Occupancy
Work"). It shall be a condition to the grant by Landlord and continued
effectiveness of such license that:

             (i) Tenant shall give to Landlord a written request to have such
access to the Premises not less than five (5) days prior to the date on which
such access will commence, which written request shall contain or shall be
accompanied by each of the following items, all in form and substance reasonably
acceptable to Landlord: (a) a detailed description of and schedule

                                    EXHIBIT B
                                       3
<PAGE>   38

for Tenant's Pre-Occupancy Work; (b) the names and addresses of all contractors,
subcontractors and material suppliers and all other representatives of Tenant
who or which will be entering the Premises on behalf of Tenant to perform
Tenant's Pre-Occupancy Work or will be supplying materials for such work, and
the approximate number of individuals, itemized by trade, who will be present in
the Premises; (c) copies of all contracts, subcontracts and material purchase
orders pertaining to Tenant's Pre-Occupancy Work; (d) copies of all plans and
specifications pertaining to Tenant's Pre-Occupancy Work; (e) copies of all
licenses and permits in connection with the performance of Tenant's
Pre-Occupancy Work; (f) certificates of insurance (in amounts satisfactory to
Landlord and with the parties identified in, or required by, the Lease named as
additional insureds) and instruments of indemnification against all claims,
costs, expenses, damages and liabilities which may arise in connection with
Tenant's Pre-Occupancy Work; and (g) assurances of the ability of Tenant to pay
for all of Tenant's Pre-Occupancy Work; and/or a letter of credit or other
security deemed appropriate by Landlord securing Tenant's lien-free completion
of Tenant's Pre-Occupancy Work.

             (ii) Such pre-term access by Tenant and its representatives shall
be subject to scheduling by Landlord.

             (iii) Tenant's employees, agents, contractors, workmen, mechanics,
suppliers and invitees shall work in harmony and not interfere with Landlord or
Landlord's agents in performing the Work and any Additional Work in the
Premises, Landlord's work in other premises and in common areas of the Building,
or the general operation of the Building. If at any time any such person
representing Tenant shall cause or threaten to cause such disharmony or
interference, including labor disharmony, and Tenant fails to immediately
institute and maintain such corrective actions as directed by Landlord, then
Landlord may withdraw such license upon twenty-four (24) hours' prior written
notice to Tenant.

                  (a) Any such entry into and occupancy of the Premises by
Tenant or any person or entity working for or on behalf of Tenant shall be
deemed to be subject to all of the terms, covenants, conditions and provisions
of the Lease, specifically including the provisions of Section IX thereof
(regarding Tenant's improvements and alterations to the Premises), and excluding
only the covenant to pay Rent. Landlord shall not be liable for any injury, loss
or damage which may occur to any of Tenant's Pre-Occupancy Work made in or about
the Premises or to property placed therein prior to the commencement of the term
of the Lease, the same being at Tenant's sole risk and liability. Tenant shall
be liable to Landlord for any damage to the Premises or to any portion of the
Work or Additional Work caused by Tenant or any of Tenant's employees, agents,
contractors, workmen or suppliers. In the event that the performance of Tenant's
Pre-Occupancy Work causes extra costs to Landlord or requires the use of
elevators during hours other than 7:00 a.m. to 6:00 p.m. on Monday through
Friday (excluding holidays) or of other Building services, Tenant shall
reimburse Landlord for such extra cost and/or shall pay Landlord for such
elevator service or other Building services at Landlord's standard rates then in
effect.

        10. Lease Provisions. The terms and provisions of the Lease, insofar as
they are applicable to this Work Letter, are hereby incorporated herein by
reference. All amounts payable by Tenant to Landlord hereunder shall be deemed
to be additional Rent under the Lease and, upon any default in the payment of
same, Landlord shall have all of the rights and remedies provided for in the
Lease.

        11. Miscellaneous.

             (i) This Work Letter shall be governed by the laws of the state of
California.

             (ii) This Work Letter may not be amended except by a written
instrument signed by the party or parties to be bound thereby.

             (iii) Any person signing this Work Letter on behalf of Tenant
warrants and represents he/she has authority to sign and deliver this Work
Letter and bind Tenant.

             (iv) Notices under this Work Letter shall be given in the same
manner as under the Lease.

                                    EXHIBIT B
                                       4
<PAGE>   39

             (v) The headings set forth herein are for convenience only.

             (vi) This Work Letter sets forth the entire agreement of Tenant and
Landlord regarding the Work.

             (vii) In the event that the final working drawings and
specifications are included as part of the Initial Plan attached hereto, or in
the event Landlord performs the Work without the necessity of preparing working
drawings and specifications, then whenever the term "Working Drawings" is used
in this Agreement, such term shall be deemed to refer to the Initial Plan and
all supplemental plans and specifications approved by Landlord.

             (viii) Lessor recommends that the Premises' HVAC systems and
distribution be re-engineered and rebalanced anytime modifications are made to
Lessee's Premises. In the event Lessee elects not to re-engineer and/or
rebalance the HVAC systems, then Lessee shall have deemed to have accepted the
HVAC in its current as-is condition at the date of execution of this document,
and should it be deemed necessary, at anytime during the Term, to modify the
distribution of the HVAC to the Premises, all costs associated shall be at
Lessee's sole cost and expense.

        12. Exculpation of Landlord and Seagate. Notwithstanding anything to the
contrary contained in this Lease or in any exhibits, Riders or addenda hereto
attached (collectively the "Lease Documents"), it is expressly understood and
agreed by and between the parties hereto that: (a) the recourse of Tenant or its
successors or assigns against Landlord with respect to the alleged breach by or
on the part of Landlord of any representation, warranty, covenant, undertaking
or agreement contained in any of the Lease Documents or otherwise arising out of
Tenant's use of the Premises or the Building (collectively, "Landlord's Lease
Undertaking") shall extend only to Landlord's interest in the real estate of
which the Premises demised under the Lease Documents are a part ("Landlord's
Real Estate") and not to any other assets of Landlord or its beneficiaries; and
(b) no personal liability or personal responsibility of any sort with respect to
any of Landlord's Lease Undertakings or any alleged breach thereof is assumed
by, or shall at any time be asserted or enforceable against, Landlord, OTR, an
Ohio general partnership, Seagate Properties, Inc., Seagate Realty Advisors, or
against any of their respective directors, officers, employees, agents,
constituent partners, beneficiaries, trustees or representatives. Tenant
acknowledges that this Lease is executed by certain general partners of OTR
and/or Seagate Realty Advisors, not individually but solely on behalf of, and as
the authorized nominee and agent for, the State Teachers Retirement Board of
Ohio, and Tenant and all persons dealing with Landlord waive any right to bring
a cause of action against the individuals executing this Lease on behalf of
Landlord and must look solely to the assets of State Teachers Retirement Board
of Ohio for the enforcement of any claim against Landlord.

        IN WITNESS WHEREOF, this Work Letter Agreement is executed as of the
aforementioned date.

LANDLORD:                              TENANT:

OTR, an Ohio general                   CHEMCONNECT, INC., A DELAWARE
partnership, as Nominee of The         CORPORATION
State Teachers Retirement
Board of Ohio, a statutory
organization created by the
laws of Ohio                           By:
                                          --------------------------------------
By: SEAGATE REALTY ADVISORS, A         Its:
    CALIFORNIA GENERAL                     -------------------------------------
    PARTNERSHIP, ITS DULY              Date:
    AUTHORIZED AGENT                        ------------------------------------

By:
   -----------------------------------
Its:
    ----------------------------------
Date:
     ---------------------------------

                                    EXHIBIT B
                                       5
<PAGE>   40

                                   SCHEDULE I

                             COPIES OF INITIAL PLAN

The Premises is located adjacent to Suite 250 in the west wing of the Building
and bounded by a public corridor to the north and east of the Premises. Please
see floor plan below:

                            [Diagram of Leased Space]

                                   SCHEDULE I
<PAGE>   41

                                    EXHIBIT C

                              RULES AND REGULATIONS

        1. The sidewalks, entrances, passages, courts, elevators, vestibules,
stairways, corridors or halls shall not be obstructed or used for any purpose
other than ingress and egress. The halls, passages, entrances, elevators,
stairways, balconies and roof are not for the use of the general public, and
Landlord shall in all cases retain the right to control or prevent access
thereto by all persons whose presence in the judgment of Landlord shall be
prejudicial to the safety, character, reputation or interests of Landlord and
its tenants, provided that nothing herein contained shall be to prevent such use
by persons with whom the tenant normally deals in the ordinary course of its
business unless such persons are engaged in illegal activities. No tenant and no
employees of any tenant shall go upon the roof of the Building without the
written consent of Landlord.

        2. No awnings or other projections shall be attached to the outside
walls or surfaces of the Building nor shall the interior or exterior of any
windows be coated without the prior written consent of Landlord. Except as
otherwise specifically approved by Landlord, all electrical ceiling fixtures
hung in offices or spaces within the Building must be fluorescent and of
quality, type, design and bulb color approved by Landlord. Tenant shall not
place anything or allow anything to be placed near the glass of any window,
door, partition or wall which may appear unsightly from outside the Premises.

        3. No sign, picture, plaque, advertisement, notice or other material
shall be exhibited, painted, inscribed or affixed by any tenant or any part of,
or so as to be seen from the outside of, the Premises or the Building without
the prior written consent of Landlord. In the event of the violation of the
foregoing by any tenant, Landlord may remove the same without any liability, and
may charge the expense incurred in such removal to the tenant violating this
rule. Interior signs on doors and the directory tablet shall be inscribed,
painted or affixed for each tenant by Landlord at the expense of such tenant,
and shall be of a size, color and style acceptable to Landlord.

        4. The toilets and wash basins and other plumbing fixtures shall not be
used for any purpose other than those for which they were constructed, and no
sweepings, rubbish, rags or other substances shall be thrown therein. All damage
resulting from any misuse of the fixtures shall be borne by the tenant who, or
whose servants, employees, agents, visitors or licensees, shall have caused the
same.

        5. No tenant or its officers, agents, employees or invitees shall mark,
paint, drill into, or in any way deface any part of the Premises or the
Building. No boring, cutting or stringing of wires or laying of linoleum or
other similar floor coverings shall be permitted except with the prior written
consent of Landlord and as Landlord may direct.

        6. No bicycles, vehicles or animals of any kind shall be brought into or
kept in or about the Premises and no cooking shall be done or permitted by any
tenant on the Premises except that microwave cooking in a UL-approved microwave
oven and the preparation of coffee, tea, hot chocolate and similar items for the
tenant and its employees and business visitors shall be permitted. Tenant shall
not cause or permit any unusual or objectionable odors to escape from the
Premises

        7. The Premises shall not be used for manufacturing or for the storage
of merchandise except as such storage may be incidental to the use of the
Premises for general office purposes. No tenant shall engage or pay any
employees on the Premises except those actually working for such tenant on the
Premises nor advertise for laborers giving an address at the Premises. The
Premises shall not be used for lodging or sleeping or for any immoral or illegal
Purposes.

        8. No tenant or its officers, agents, employees or invitees shall make,
or permit to be made any unseemly or disturbing noises, sounds or vibrations or
disturb or interfere with occupants of this or neighboring buildings or Premises
or those having business with them whether by the use of any musical instrument,
radio, phonograph, unusual noise, or in any other way.

                                    EXHIBIT C
                                       1
<PAGE>   42

        9. No tenant or its officers, agents, employees or invitees shall throw
anything out of doors, balconies or down the passageways.

        10. Tenant shall not maintain armed security in or about the Premises
nor possess any weapons, explosives, combustibles or other hazardous devices in
or about the Building and/or Premises.

        11. No tenant or its officers, agents, employees or invitees shall at
any time use, bring or keep upon the Premises any flammable, combustible,
explosive, foul or noxious fluid, chemical or substance, or do or permit
anything to be done in the leased Premises, or bring or keep anything therein,
which shall in any way increase the rate of fire insurance on the Building, or
on the property kept therein, or obstruct or interfere with the rights of other
tenants, or in any way injure or annoy them, or conflict with the regulations of
the Fire Department or the fire laws, or with any insurance policy upon the
Building, or any part thereof, or with any rules and ordinances established by
the Board of Health other governmental authority.

        12. No additional locks or bolts of any kind shall be placed upon any of
the doors or windows by any tenant, nor shall any changes be made in existing
locks or the mechanism thereof. Each tenant must, upon the termination of this
tenancy, restore to Landlord all keys of stores, offices, and toilet rooms,
either furnished to, or otherwise procured by, such tenant, and in the event of
the loss of any keys so furnished, such tenant shall pay to Landlord the cost of
replacing the same or of changing the lock or locks opened by such lost key if
Landlord shall deem it necessary to make such change.

        13. All removals, or the carrying in or out of any safes, freight,
furniture, or bulky matter of any description must take place during the hours
which Landlord may determine from time to time. The moving of safes or other or
bulky matter of any kind must be made upon previous notice to the manager of the
Building and under his or her supervision, and the persons employed by any
tenant for such work must be acceptable to Landlord. Landlord reserves the right
to inspect all safes, freight or other bulky articles to be brought into the
Building and to exclude from the Building all safes, freight or other bulky
articles which violate any of these Rules and Regulations or the Lease of which
these Rules and Regulations are a part. Landlord reserves the right to prohibit
or impose conditions upon the installation on the Premises of heavy objects
which might overload the building floors. Landlord will not be responsible for
loss of or damage to any safes, freight, bulky articles or other property from
any cause, and all damage done to the Building by moving or maintaining any such
safe or other property shall be repaired at the expense of the tenant.

        14. No tenant shall purchase or otherwise obtain for use in the Premises
water, ice, towel, vending machine, janitorial, maintenance or other like
services, or accept barbering or bootblacking services, except from persons
authorized by Landlord, and at hours and under regulations fixed by Landlord.

        15. Landlord shall have the right to prohibit any advertising by any
tenant which, in Landlord's opinion, tends to impair the reputation of the
Building or its desirability as an office building and upon written notice from
Landlord any tenant shall refrain from or discontinue such advertising.

        16. Landlord reserves the right to exclude from the Building between the
hours of 10:00 p m. and 7:00 a.m. and at all hours of Saturdays, Sundays and
legal holidays all persons who do not present a pass signed by Landlord.
Landlord shall furnish passes to persons for whom any tenant requests in
writing. Each tenant shall be responsible for all persons for whom he requests
passes and shall be liable to Landlord for all acts of such persons. Landlord
shall in no case be liable for damages for any error with regard to the
admission to or exclusion from the Building of any person. In the case of
invasion, mob, riot, public excitement or other commotion, Landlord reserves the
right to prevent access to the Building during the continuance of the same, by
the closing of the gates and doors or otherwise, for the safety of the tenants
and others and the protection of the Building and the property therein.

        17. Any outside contractor employed by any tenant shall, while in the
Building, be subject to the prior written approval of Landlord and subject to
the Rules and Regulations of the Building. Tenant shall be responsible for all
acts of such persons and

                                    EXHIBIT C
                                       2
<PAGE>   43

Landlord shall not be responsible for any loss or damage to property in the
Premises, however occurring.

        18. All doors opening onto public corridors shall be kept closed, except
when in use for ingress and egress, and left locked when not in use.

        19. The requirements of tenants will be attended to only upon
application to the Office of the Building.

        20. Canvassing, soliciting and peddling in the Building are prohibited
and each tenant shall cooperate to prevent the same.

        21. All office equipment of any electrical or mechanical nature shall be
placed by tenants in the Premises in settings approved by Landlord, to absorb or
prevent any vibration, noise or annoyance.

        22. No air conditioning unit or other similar apparatus shall be
installed or used by any tenant without the written consent of Landlord.

        23. There shall not be used in any space, or in the public halls of the
Building either by any tenant or others, any hand trucks except those equipped
with rubber tires and side guards.

        24. Landlord will direct electricians as to where and how telephone and
telegraph wires are to be introduced. No boring or cutting for wires or
stringing of wires will be allowed without written consent of Landlord. The
location of telephones, call boxes and other office equipment affixed to the
Premises shall be subject to the approval of Landlord. All such work shall be
effected pursuant to permits issued by all applicable governmental authorities
having jurisdiction.

        25. No vendor with the intent of selling such goods shall be allowed to
transport or carry beverages, food, food containers, etc., on any passenger
elevators. The transportation of such items shall be via the service elevators
in such manner as prescribed by Landlord.

        26. Tenants shall cooperate with Landlord in the conservation of energy
used in or about the Building, including without rotation, cooperating with
Landlord in obtaining maximum effectiveness of the cooling system by closing
drapes or other window coverings when the sun's rays fall directly on windows of
the Premises, and closing windows and doors to prevent heat loss. Tenant shall
not obstruct, alter, or in any way impair the efficient operation of Landlord's
heating, lighting, ventilating and air conditioning system and shall not place
bottles, machines, parcels, or any other articles on the induction unit
enclosure so as to interfere with air flow. In addition, Tenant shall not
obstruct, alter, or in any way impair the proper circulation and regular
maintenance and repair of the induction unit by placing furniture less than 18
inches from the induction unit. Tenant shall not tamper with or change the
setting of any thermostats or temperature control valves, and shall in general
use heat, gas, electricity, air conditioning equipment and heating equipment in
a manner compatible with sound energy conservation practices and standards.

        27. All parking ramps and areas, pedestrian walkways, plazas, and other
public areas forming a part of the Building shall be under the sole and absolute
control of Landlord with the exclusive right to regulate and control these
areas. Tenant agrees to conform to the rules and regulations that may be
established by Landlord for these areas from time to time.

        28. Landlord reserves the right to exclude or expel from the Building
any person who, in the judgment of Landlord, is intoxicated or under the
influence of liquor or drugs, or who shall in any manner do any act in violation
of any of the rules and regulations of the Building.

        29. Tenant and its employees, agents, subtenants, contractors and
invitees shall comply with all applicable "nonsmoking" ordinances and,
irrespective of such ordinances, shall not smoke or permit smoking of
cigarettes, cigars or pipes outside of Tenant's Premises (including plaza areas)
in any portions of the Building except areas specifically designated as

                                    EXHIBIT C
                                       3
<PAGE>   44

smoking areas by Landlord. If required by applicable ordinance, Tenant shall
provide smoking areas within Tenant's Premises.

                                    EXHIBIT C
                                       4
<PAGE>   45

                                    EXHIBIT E

                            TENANT ACCEPTANCE LETTER

September 3, 1999

CHEMCONNECT, Inc.
44 Montgomery Street, Suite 250
San Francisco, CA 94104

Re:     44 Montgomery Street, Suite 280

Dear Tenants:

Please sign below to consign that you accept the Premises as complete under that
certain Lease Agreement dated September 3, 1999 by and between OTR, an Ohio
general partnership, as Nominee for the State Teachers Retirement Board of Ohio,
a statutory organization created by the laws of Ohio, and, CHEMCONNECT, INC., a
Delaware corporation and that the Commencement Date is October 15, 1999 and the
expiration date is December 31, 2001.

                                     Sincerely,

                                     SEAGATE PROPERTIES, Inc.
                                     Managing Agent

                                     By:
                                        ---------------------------------------

Acknowledged and Agreed:             Its:
                                         --------------------------------------

Tenant:                              Date:
       ----------------------------       -------------------------------------

-----------------------------------

By:
   --------------------------------
Name:
     ------------------------------
Title:
      -----------------------------
Date:
     ------------------------------

                                    EXHIBIT E<PAGE>   1
                                                                    Exhibit 10.6

                     LIGHT HOUSE CAPITAL PARTNERS II, L.P.

                               Lease Documentation

                                Table of Contents

Tab

1.      Master Equipment Lease Agreement No. 219 dated May 5, 1999

2.      Lease Line Schedule No. 01 dated May 5, 1999

3.      Software Rider dated May 5, 1999

                Software License Assignment Agreement

4.      Equipment Schedules with Summaries to Lease Line Schedule No. 01

                Equipment Schedule No. 01 dated May 5, 1999

                Equipment Schedule No. _____ dated ____________________

                Equipment Schedule No. _____ dated ____________________

                Equipment Schedule No. _____ dated ____________________

5.      Preferred Stock Purchase Warrant

<PAGE>   2

                        MASTER EQUIPMENT LEASE AGREEMENT
                      Agreement No. 219 Dated: May 5, 1999

LESSOR:       LIGHTHOUSE CAPITAL PARTNERS II, L.P., a Delaware limited
              partnership ("Lessor"), 100 Drakes Landing Road, Suite 260,
              Greenbrae, California 94904-3121

LESSEE:       CHEMCONNECT, INC., a Delaware corporation ("Lessee")

ADDRESS: 44   Montgomery Street, Suite 250, San Francisco, California 94104

        IN CONSIDERATION of the mutual covenants contained herein, the parties
agree as follows:

        1. LEASE. Lessor leases to Lessee and Lessee leases from Lessor the
personal property described in each Equipment Schedule executed pursuant hereto,
subject to the terms and conditions of this Master Equipment Lease Agreement
("Master Lease") and the applicable Lease Line Schedule (defined below). The
"Equipment" (as defined in the Lease Line Schedule) is being leased for
commercial or business purposes only, and not for personal, home, or family
purposes. The parties agree that each Lease is a "finance lease" under the
Uniform Commercial Code (as in effect in the State of California during the term
of the Lease and referred to hereafter as the "UCC").

        2. LEASE LINE SCHEDULE. "Lease Line Schedule" means a Lease Line
Schedule in the form of EXHIBIT A, signed by Lessor and Lessee and incorporating
by reference the terms and provisions of this Master Lease.

        3. EQUIPMENT SCHEDULES. "Equipment Schedule" means an Equipment Schedule
in the form of EXHIBIT B, signed by Lessor and Lessee and incorporating, by
reference, the terms and provisions of this Master Lease and the applicable
Lease Line Schedule. Each Equipment Schedule shall constitute a separate and
independent lease (a "Lease"); the original of such Lease shall consist of the
signed Equipment Schedule and a copy of the Master Lease and applicable Lease
Line Schedule. Capitalized terms used, but not defined, in this Master Lease
have the meanings given to such terms in the applicable Lease Line Schedule or
Equipment Schedule, as the case may be.

        4. TERM AND RENTALS.

           (a) ACCEPTANCE. The Lease shall commence with respect to Equipment
described on the Equipment Schedule upon the Acceptance Date. The "Acceptance
Date" shall be the date upon which Lessee executes a Delivery and Acceptance
Certificate in the form of EXHIBIT C.

           (b) TERM AND PAYMENT OF RENT. The lease term for the Equipment shall
be the "Lease Term" set forth in the Equipment Schedule which shall commence on
the "Commencement Date" (as defined in the Lease Line Schedule). Lessee agrees
to pay to Lessor the "Rental Payments" for the Lease Term, in the amounts and at
the times set forth in the Equipment Schedule.

           (c) INTERIM PERIOD. If the Acceptance Date does not fall on the
Commencement Date, then Lessee agrees to pay to Lessor "Interim Rent" for the
period commencing on the Acceptance Date through and including the day preceding
the Commencement Date (the "Interim Period"). The Interim Rent payment for the
Interim Period shall accrue at the "Interim Rate" (as defined in the Lease Line
Schedule) and shall be due and payable in full on the Commencement Date.

           (d) LEASE TERMINATION. Lessee may terminate the Lease at the
expiration of the Lease Term or any renewal term (the "Lease Termination") by
submitting to Lessor a Notice of Election in the form of EXHIBIT D. If a Notice
of Election is not submitted by Lessee to Lessor during the "Advance Notice
Period" (as defined in the Lease Line Schedule), then the Lease Term or any
renewal Term will be automatically extended for an additional period equal to
the "Automatic Extension Period" (as defined in the Lease Line Schedule). The
Lease will continue to automatically extend until Lessee submits to Lessor a
Notice of Election. The Lease may only be terminated as

                                       1.
<PAGE>   3

expressly provided in this Section, in the applicable Lease Line Schedule or in
the applicable Equipment Schedule. Lessee agrees to continue paying rent for the
Equipment in the amount of the Rental Payment set forth in the Equipment
Schedule until the later of (i) the expiration of the Lease Term, any renewal
term and any Automatic Extension Period and (ii) either (A) the purchase option
price is paid pursuant to SECTION 6(a), or (B) a mutually agreed renewal of the
Lease takes effect pursuant to SECTION 6(b), or (C) the Equipment is returned in
the manner and condition prescribed in SECTION 6(c), in each case after delivery
of a Notice of Election.

           (e) NET LEASE. Each Equipment Schedule shall be a net lease, and
Lessee's obligation to pay all rent and other sums thereunder shall be absolute
and unconditional, and shall not be subject to any abatement, reduction,
set-off, defense, counterclaims, interruption, deferment or recoupment, for any
reason whatsoever.

        5. LATE FEE. Lessee shall pay a late charge on any rent payments or
other sums due hereunder which are past due, in the amount specified in the
Lease Line Schedule, payable on demand. In addition, interest shall accrue daily
at the "Default Rate" (as defined in the Lease Line Schedule), or if such rate
exceeds the maximum rate allowed by law, then at such maximum rate, and shall be
payable on demand.

        6. LEASE TERMINATION OPTIONS. Upon Lease Termination, Lessee will have
the option to purchase the Equipment, renew the term of the Lease, or return the
Equipment to Lessor, as set forth below. Lessee shall specify its election of a
Lease Termination Option in the Notice of Election.

           (a) PURCHASE OPTION. If Lessee exercises the option to purchase,
then, provided no Event of Default has occurred and is then continuing, Lessee
shall at the expiration of the Lease Term, renewal term or extension, as the
case may be, purchase the Equipment. The purchase price shall be the Equipment's
then fair market value ("FMV"). FMV, as applied to a purchase option, shall be
determined by Lessor based on the price a willing buyer would pay and a willing
seller would accept (neither buyer nor seller being under compulsion to act) for
the Equipment as installed and in use, giving due consideration to its
condition, utility, revenue-producing capability, and replacement costs. If
Lessee fails to agree with Lessor's good faith determination of the FMV, Lessee
shall nevertheless pay Lessor's invoice and provide Lessor with a written
request for a determination of the FMV with or prior to such payment. Within ten
(10) days after such request Lessor and Lessee shall agree on an appraiser to
determine the FMV or, lacking such agreement, shall each tender the name of an
appraiser. The appraiser(s) shall, within thirty (30) days, either agree on the
FMV or select a third appraiser, to form a committee to determine the FMV.
Determination by the appraiser(s) shall be final and binding on both parties.
Within fifteen (15) days after such determination, Lessor shall refund any
excess received over the FMV, and/or Lessee shall pay any additional amount of
the FMV above the amount previously paid. Each party shall bear the fees and
expenses of any appraiser which it names and share equally the fees and expenses
of any appraiser(s) jointly selected. If the appraised FMV is within 5% of the
amount invoiced by Lessor, then Lessee shall pay all appraiser fees and
expenses. The purchase option price shall be paid not later than the last day of
the Lease Term.

           (b) RENEWAL. If Lessee exercises the option to renew this Lease, such
renewal shall be upon the terms and conditions of this Master Lease and the
applicable Lease Line Schedule, for a rental period and rental amount to be
agreed upon by Lessee and Lessor.

           (c) RETURN. If the Notice of Election specifies return of the
Equipment, Lessee at its own risk and expense (i) will immediately return the
Equipment to Lessor in the same condition as when delivered, ordinary wear and
tear excepted, at such location as Lessor shall designate provided, however,
that Lessee's expense shall be limited to the cost of returning the Equipment
(including expenses relating to the provision of insurance) to Lessor's address
as set forth herein; and (ii) will, on request from Lessor, use best efforts to
obtain from the Equipment supplier (or other maintenance service supplier
approved by Lessor) a certificate stating that the Equipment qualifies for
continued maintenance service at the standard rates and terms then in effect.

        7. USE; MAINTENANCE.

           (a) Lessee, at its expense, shall make all necessary site
preparations and cause the Equipment to be operated in accordance with any
applicable operating manuals and manufacturer's instructions. Notwithstanding
any transfer or assignment by Lessor and provided that no Event of Default
exists hereunder, Lessee shall have the

                                       2.
<PAGE>   4

right to quietly possess and use the Equipment as provided herein without
interference by Lessor, its assigns or any other third party claiming through or
under Lessor.

           (b) Lessee shall effect and bear the expense of all necessary repair,
maintenance, operation and replacements required to be made to maintain the
Equipment in good condition, reasonable wear and tear excepted, and to comply
with all domestic and international laws to which the use and operation of the
Equipment may be or become subject, except to the extent that failure to comply
would not have an adverse effect on the Equipment or Lessor's rights hereunder.
All replacement Equipment and parts furnished in connection with such
maintenance or repair shall immediately become the property of Lessor and part
of the Equipment for all purposes hereof. All such maintenance, repair and
replacement services shall be immediately paid for and discharged by Lessee with
the result that no lien under any applicable laws will attach to the Equipment
as a result of the performance of such services or the provision of any such
material which is enforceable by the holder thereof, except for liens that are
being contested in good faith by proceedings that are being diligently pursued
and for which adequate reserves in accordance with generally accepted accounting
principles have been created.

        8. INSURANCE. Lessee shall obtain and maintain for the Lease Term (and
any renewal term or extension), at its own expense, (a) "all risk" insurance
against loss or damage to the Equipment, (b) commercial general liability
insurance (including contractual liability, products liability and completed
operations coverage) reasonably satisfactory to Lessor, and (c) such other
insurance against such other risks of loss and with such terms, as shall in each
case be reasonably satisfactory to or reasonably required by Lessor (as to
carriers, amounts and otherwise). The amount of the "all risk" insurance shall
be greater than or equal to the Stipulated Loss Value (as defined in SECTION 9
below) of all Equipment outstanding under the Lease Line Schedule, and must
otherwise be reasonably satisfactory to Lessor as of each anniversary date of
this Lease. Any increase in the amount of such insurance coverage, other than
"all risk", reasonably requested by Lessor shall be put into effect on the next
succeeding renewal date of such insurance.

        Each "all risk" policy shall: (i) name Lessor as sole loss payee with
respect to the Equipment, (ii) provide for each insurer's waiver of its right of
subrogation against Lessor and Lessee, and (iii) provide that such insurance
shall not be invalidated by any action of, or breach of warranty by, Lessee of a
provision of any of its insurance policies, and shall waive set-off,
counterclaim or offset against Lessor.

        Each liability policy shall name Lessor as an additional insured and
provide that such insurance shall have cross-liability and severability of
interest endorsements (which shall not increase the aggregate policy limits of
Lessee's insurance).

        All insurance policies shall provide that Lessee's insurance shall be
primary without a right of contribution of Lessor's insurance, if any, or any
obligation on the part of Lessor to pay premiums of Lessee, and shall contain a
clause requiring the insurer to give Lessor at least 30 days' prior written
notice of its cancellation (other than cancellation for non-payment for which 10
days' notice shall be sufficient). Lessee shall on or prior to the date of
Equipment Schedule No. 01 and prior to each policy renewal, furnish to Lessor
certificates of insurance or other evidence satisfactory to Lessor that such
insurance coverage is in effect. Lessee further agrees to give Lessor prompt
notice of any damage to, or loss of, the Equipment, or any part thereof.

        9. LOSS OR DAMAGE. If any items of Equipment shall become lost, stolen,
destroyed, or damaged beyond repair for any reason, or in the event of
condemnation, confiscation, seizure or requisition of title to or use of such
items (collectively, an "Event of Loss"), Lessee shall, subject to the second
paragraph of this SECTION 9, promptly pay to Lessor the applicable Stipulated
Loss Value of the Equipment subject to the Event of Loss. Upon payment by Lessee
of the Stipulated Loss Value, Lessor will transfer to Lessee, "AS IS, WHERE IS,
WITHOUT RECOURSE, REPRESENTATION OR WARRANTY," all of Lessor's right, title and
interest, if any, in such items of Equipment. The "Stipulated Loss Value"
payable by Lessee under this Lease shall be an amount equal to the product of
(a) Lessor's Cost of the affected Equipment and (b) the percentage set forth in
the table attached to the applicable Lease Line Schedule as ANNEX A opposite the
Rental Payment number next following the Event of Loss. Stipulated Loss Values
and Rental Payments shall not be prorated.

Notwithstanding any other provision hereof, Lessee shall have the right to
replace an item of Equipment that is the subject of an Event of Loss, with a
replacement item of Equipment (the "Replacement Equipment") reasonably

                                       3.
<PAGE>   5

acceptable to Lessor, rather than pay the applicable Stipulated Loss Value of
such Equipment, provided that all of the following conditions precedent are
satisfied (i) no Event of Default has occurred and is continuing, (ii) Lessee
conveys to Lessor good title to the Replacement Equipment free and clear of all
liens and encumbrances, (iii) Lessee executes and delivers bills of sale, lease
supplements and such other documents relating to the Replacement Equipment that
Lessor reasonably determines are necessary to transfer title to the Replacement
Equipment to Lessor and to give notice of or to perfect Lessor's rights, title
and interest therein, (iv) the Replacement Equipment is in as good condition and
has the same fair market value and residual value, utility, and remaining useful
life as the Equipment being replaced, and (v) Lessee indemnifies Lessor against
any adverse tax consequences relating to such replacement.

        10. TITLE, INSPECTION AND LOCATION.

            (a) TITLE. Lessor and Lessee confirm their intent that title to the
Equipment shall remain in Lessor (or its successors and assigns) exclusively. If
requested by Lessor, Lessee will affix plates or markings on the Equipment and
on any operating manuals and manufacturer's instructions indicating the
interests of Lessor and its assigns therein, and Lessee will not allow any other
indicia of ownership or other interest in the Equipment to be placed on the
Equipment. Lessee shall not sell, assign, grant a security interest in, sublet,
pledge, hypothecate or otherwise encumber or suffer a lien upon or against this
Lease or the Equipment.

            (b) INSPECTION. Lessor (through any of its officers, employees or
agents) shall have the right to inspect the Equipment during regular business
hours, with reasonable notice, and in compliance with Lessee's reasonable
security procedures; provided, that such inspections will be conducted no more
often then once every six (6) months unless an Event of Default, or event which,
with notice or lapse of time or both, would become an Event of Default, has
occurred and is continuing.

            (c) LOCATION. In the case of Equipment other than mobile Equipment,
Lessee may move such Equipment from the installation address shown on the
Equipment Schedule (or any other location for which Lessee has complied with
this provision) only if (i) the new location is within the continental United
States, and (ii) Lessee gives at least 30 days' prior written notice of the
relocation and provides UCC financing statements, landlord waivers or such other
documentation as Lessor reasonably requests to protect its interest in the
Equipment. In the case of mobile equipment (including, without limitation,
lap-top computers), Lessee agrees to obtain from the person using such mobile
Equipment and deliver to Lessor, an Acknowledgment in the form of EXHIBIT F.

            (d) Lessee shall keep copies of all operating manuals and
manufacturer's instructions with respect to the Equipment in good condition at
the locations specified in SECTION 10(c).

        11. LESSEE'S REPRESENTATIONS, WARRANTIES AND WAIVERS. Upon execution of
the Master Lease and each Equipment Schedule, Lessee warrants and represents the
following:

            (a) Lessee is a corporation duly organized, validly existing and in
good standing under the laws of its state of incorporation. Lessee has full
power and authority and all necessary licenses and permits to carry on its
business as presently conducted, to own or hold under lease its properties and
to enter into this Master Lease, the Lease Line Schedule and each Equipment
Schedule and to perform its obligations thereunder; and Lessee is duly qualified
to do business as a foreign corporation and is in good standing in each
jurisdiction in which the character of its properties or the nature of its
business or the performance of its obligations under this Master Lease, the
Lease Line Schedule and any Equipment Schedule requires such qualification,
except for such jurisdictions in which failure to qualify would not have a
material adverse effect on Lessee.

            (b) The execution and delivery by Lessee of this Master Lease, the
Lease Line Schedule and each Equipment Schedule and the performance by Lessee of
its obligations thereunder have been duly authorized by all necessary corporate
action on the part of Lessee; and do not and will not contravene the provisions
of, or constitute a default (either with or without notice or lapse of time, or
both) under, or result in the creation of any lien upon, the Equipment or any
property of Lessee under any indenture, mortgage, contract or other instrument
to which Lessee is a party or by which Lessee or its properties is bound.

                                       4.
<PAGE>   6

            (c) No consent or approval of, giving of notice to, registration
with, or taking of any other action by, any state, federal, foreign or other
governmental commission, agency or regulatory authority or any other person or
entity is required for the consummation or performance by Lessee of the
transactions contemplated under this Master Lease, the Lease Line Schedule and
each Equipment Schedule.

            (d) This Master Lease, the Lease Line Schedule and each Equipment
Schedule, when executed by Lessee, constitute legal, valid and binding
agreements of Lessee enforceable against Lessee in accordance with their terms,
except as limited by any bankruptcy, insolvency, reorganization, or other
similar laws of general application affecting the enforcement of creditor or
Lessor rights and general principles of equity.

            (e) There are no actions, suits or proceedings pending or threatened
against or affecting Lessee or any property of Lessee in any court, before any
arbitrator of any kind or before or by any federal state, municipal or other
government department, commission, board, bureau, agency or instrumentality
(collectively "Governmental Body"), which, if adversely determined, would
materially adversely affect the business, financial condition, assets, or
operations of Lessee, or adversely affect the ability of Lessee to perform its
obligations under this Master Lease, the Lease Line Schedule and each Equipment
Schedule; and Lessee is not in default with respect to any order of any court,
arbitrator or Governmental Body or with respect to any material loan agreement,
debt instrument or contract with a supplier or customer of Lessee, except as
disclosed in writing to Lessor.

            (f) To the extent permitted by applicable law, Lessee waives any and
all rights and remedies to: (i) cancel this Lease; (ii) repudiate this Lease;
(iii) reject the Equipment; (iv) revoke acceptance of the Equipment; (v) recover
damages from Lessor for any breaches of warranty or for any other reason; (vi)
claim a security interest in the Equipment in Lessee's possession or control for
any reason; (vii) deduct from Rental Payments all or any part of any claimed
damages resulting from Lessor's default, if any, under this Lease; (viii) accept
partial delivery of the Equipment; (ix) "cover" by making any purchase or lease
of or contract to purchase or lease equipment in substitution for Equipment
designated in the Lease; (x) recover any direct, general, special, incidental,
indirect, exemplary or consequential damages, for any reason whatsoever; and
(xi) obtain specific performance, replevin, detinue, sequestration, claim and
delivery or the like for any Equipment identified to this Lease. To the extent
permitted by applicable law, Lessee also waives any rights now or hereafter
conferred by statute or otherwise which may require Lessor to sell, lease or
otherwise use any Equipment in mitigation of Lessor's damages or which may
otherwise limit or modify any of Lessor's rights or remedies.

        12. ASSIGNMENT BY LESSOR. LESSEE ACKNOWLEDGES THAT LESSOR MAY SELL,
ASSIGN, GRANT A SECURITY INTEREST IN, OR OTHERWISE TRANSFER ALL OR ANY PART OF
ITS RIGHTS, TITLE AND INTEREST IN THIS LEASE AND THE EQUIPMENT WITHOUT NOTICE TO
OR CONSENT OF LESSEE. Upon Lessor's written notice to Lessee that this Lease, or
the right to the Rental Payments hereunder, have been assigned, Lessee shall, if
requested, pay directly to Lessor's assignee without abatement, deduction or
set-off all amounts which become due hereunder. Lessee waives and agrees it will
not assert against Lessor's assignee any counterclaim or set-off in any action
for rent under this Lease. Upon the assignment of this Lease, Lessor's assignee
shall have and be entitled to exercise any and all rights and remedies (but none
of the obligations) of Lessor hereunder, and all references herein to Lessor
shall include Lessor's assignee. Lessee acknowledges that any assignment or
transfer by Lessor does not materially change Lessee's duties or obligations
under this Lease nor materially increase the burdens or risks imposed on Lessee.

        13. ASSIGNMENT BY LESSEE. LESSEE MAY NOT, WITHOUT LESSOR'S PRIOR WRITTEN
CONSENT, (i) ASSIGN THIS LEASE, WHETHER BY OPERATION OF LAW OR OTHERWISE, OR
SUBLEASE THE EQUIPMENT OR ANY PART THEREOF OR (ii) ASSIGN, GRANT A SECURITY
INTEREST IN, OR OTHERWISE TRANSFER ALL OR ANY PART OF ITS RIGHTS, TITLE AND
INTEREST IN AND TO THIS LEASE OR THE EQUIPMENT. In the event Lessee makes an
assignment, sublease or other transfer (to which Lessor has consented), Lessee
shall not thereby be relieved of its duties and obligations hereunder, for which
it shall remain fully responsible and liable (independent of its assignee).

Notwithstanding the foregoing, in the event of a merger, sale of substantially
all of the assets or other reorganization involving Lessee in which the
shareholders of Lessee immediately prior to such transaction own less than 50%
of the voting securities of the surviving entity or purchaser of assets (or its
parent) in such transaction, Lessor shall not

                                       5.
<PAGE>   7

withhold its consent to the assignment of this Lease to the successor entity if
each of the following conditions precedent is satisfied:

        (i) the successor entity as of the date of such assignment meets
Lessor's then current credit standards, as determined by Lessor in Lessor's sole
reasonable judgment;

        (ii) Lessee gives Lessor at least thirty (30) days prior written notice
of such merger, sale of assets or other reorganization;

        (iii) such merger, sale of assets or other reorganization does not
adversely affect the rights of Lessor;

        (iv) the corporation that results from such merger or other
reorganization or which purchases the assets in the case of a sale of assets
(the "Surviving Corporation") shall have executed and delivered to Lessor an
agreement in form and substance reasonably satisfactory to Lessor, containing an
assumption by Surviving Corporation of the due and punctual performance and
observance of each covenant and condition of Lessee in the Master Lease, Lease
Line Schedule and Equipment Schedules (the "Lease Documents") and making
representations and warranties with respect to the Surviving Corporation similar
in scope and substance to the representations and warranties made by Lessee in
the Lease Documents;

        (v) the Surviving Corporation executes any precautionary financing
statements or amendments thereto reasonably requested by Lessor; and

        (vi) immediately after giving effect of such merger, sale of assets or
other reorganization, no Event of Default or, event which with the lapse of time
or giving of notice or both, would result in an Event of Default shall have
occurred and be continuing.

        14. TAXES.

            (a) Lessee shall comply with all applicable federal, state, local,
foreign and international laws, regulations and orders relating to this Lease.
Lessee assumes liability for, and shall pay when due, and on a net after-tax
basis shall indemnify and defend Lessor against, all federal, state, local,
foreign and international fees, taxes and government charges (including, without
limitation, interest and penalties) of any nature imposed upon or in any way
relating to Lessor, Lessee, any item of Equipment or this Lease, except federal,
state and local taxes on or measured by Lessor's net income (other than any such
tax which is in substitution for or relieves Lessee from the payment of taxes it
would otherwise be obligated to pay to or reimburse Lessor for as herein
provided). Lessee shall at its expense file when due with the appropriate
authorities any and all tax and similar returns and reports required to be filed
with respect thereto or, if requested by Lessor, notify Lessor of all such
requirements and furnish Lessor with all information required for Lessor to
effect such filings, which filings shall also be at Lessee's expense. Any fees,
taxes or other charges paid by Lessor upon failure of Lessee to make such
payments shall at Lessor's option become immediately due from Lessee to Lessor.

            (b) This Lease has been entered into on the assumption that Lessor
shall be entitled to all deductions, credits, and other tax benefits as are
provided in the Internal Revenue Code of 1986, including amendments as may occur
(the "Code"), to an owner of property including, without limitation,
depreciation deductions and interest deductions with respect to any debts
incurred to finance the purchase of the Equipment. If, as a result of any acts,
omissions or misrepresentations by Lessee, Lessor's projected after-tax economic
return resulting from ownership and lease of the Equipment is reduced, then
Lessee's Rental Payments shall be increased in an amount (based on Lessor's
reasonable calculations) sufficient to provide the same net after-tax economic
return as if such acts or omissions or changes had not occurred. Appropriate
increases shall also be made in the applicable Stipulated Loss Values for this
Lease. In the event the Equipment is sold by Lessor to another party, the net
after-tax economic returns considered shall be those of such other party.

        15. EQUIPMENT WARRANTIES. Lessee acknowledges that (i) Lessee has
selected the supplier of the Equipment, (ii) Lessor acquired the goods or the
right to possession and use of the goods in connection with the Lease, and (iii)
Lessee received a copy of the contract by which Lessor acquired the Equipment or
the right to possession and use of the Equipment before signing the Lease.
LESSOR MAKES NO EXPRESS OR IMPLIED

                                       6.
<PAGE>   8

WARRANTIES INCLUDING THOSE OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE
WITH RESPECT TO THE EQUIPMENT AND DISCLAIMS THE SAME. Lessor shall have no
liability for any damages, whether direct, indirect, general, special,
incidental, exemplary or consequential, incurred by Lessee as a result of any
defect or malfunction of the Equipment. Lessee shall look solely to the
Equipment supplier for any and all claims related to the Equipment. Lessor
assigns to Lessee, for and during the Lease Term, any warranty on the Equipment
provided by the supplier. Lessor and Lessee agree that all limitations on
remedies and liability contained in this Lease represent a reasonable allocation
of risks that is part of the fundamental bargain between the parties.

        16. EVENTS OF DEFAULT. An Event of Default shall occur if Lessee (i)
fails to pay any Rental Payment or other payment required under the Lease when
due and such failure continues for a period of five (5) days after written
notice from Lessor; or (ii) fails to perform or observe any other covenant,
condition or agreement to be performed or observed by it or breaches any
provision contained in the Lease or in any other document furnished to Lessor in
connection herewith, and such failure or breach continues for a period of thirty
(30) days after written notice from Lessor; or (iii) without Lessor's consent,
attempts to assign this Lease or sell, transfer, encumber, part with possession,
or sublet any item of Equipment; or (iv) makes any representation or warranty
herein or in any document furnished by Lessee in connection herewith, which
shall have been materially false or inaccurate when made or at the time to which
such representation or warranty relates; or (v) shall commit an act of
bankruptcy or become insolvent or bankrupt or make an assignment for the benefit
of creditors or consent to the appointment of a Trustee or Receiver or either
shall be appointed for Lessee or for a substantial part of its property without
its consent, or bankruptcy reorganization, or insolvency proceedings shall be
instituted by or against Lessee, and, if instituted against Lessee, shall not be
vacated or dismissed within sixty (60) days. Any Event of Default shall be
deemed material and a substantial impairment of Lessor's interests for the
purposes of this Lease, the UCC, and any other applicable law.

        17. REMEDIES. Upon the occurrences of any Events of Default and at any
time thereafter, provided such Event of Default is then continuing, Lessor may,
in its discretion, do any one or more of the following:

            (a) cancel any or all Leases which reference this Master Lease or
the Lease Line Schedule, upon notice to Lessee;

            (b) recover any accrued and unpaid Rental Payments and other amounts
which are due and owing under the Leases so canceled on the Rental Payment Date
immediately preceding the date on which Lessor obtains possession of the
Equipment (or such earlier date as judgment is entered in favor of Lessor) (the
"Determination Date"), plus interest at the Default Rate;

            (c) with or without canceling this Lease, recover such Stipulated
Loss Value as of the Rental Payment Date immediately preceding the Determination
Date;

            (d) recover any amounts due under any indemnity then determinable,
plus interest at the Default Rate;

            (e) require that Lessee provide the return and certification of the
Equipment in accordance with SECTION 6(c) hereof;

            (f) enter the premises where such Equipment is located and take
immediate possession of and remove the same, all without liability to Lessor or
its agents for such entry;

            (g) sell any or all of the Equipment at public or private sale, with
or without notice to Lessee or advertisement, or otherwise dispose of, hold,
use, operate, lease to others or keep idle such Equipment, all free and clear of
any rights of Lessee with the exception of providing Lessee, upon written
request, an accounting of the proceeds with respect thereto; and

            (h) exercise any other right or remedy which may be available to it
under the UCC or other applicable law including the right to recover damages for
the breach hereof.

                                       7.

<PAGE>   9

        In addition, Lessee shall be liable for, and reimburse Lessor for, all
reasonable legal fees and all commercially reasonable costs and expenses
incurred by Lessor as a result of the foregoing defaults or the exercise of
Lessor's remedies, including without limitation recovering possession of the
Equipment, selling or leasing the Equipment (including broker's and sales
representative's fees and commissions), and placing any Equipment in the
condition and obtaining the certificate required by SECTION 6(c) hereof. No
remedy referred to in this Section is intended to be exclusive, but each shall
be cumulative and in addition to any other remedy referred to above or otherwise
available to Lessor at law or in equity. No express or implied waiver by Lessor
of any default shall constitute a waiver of any other default by Lessor, or a
waiver of any of Lessor's rights.

        18. INDEMNIFICATION. Lessee assumes liability for, and shall pay when
due, and shall indemnify, reimburse and hold each Indemnified Person (defined
below) harmless from and against all Claims (defined below), directly or
indirectly relating to or arising out of the acquisition, use, manufacture,
purchase, shipment, transportation, delivery, installation, lease or sublease,
ownership, operation, possession, control, storage, return or condition of any
item of Equipment (regardless of whether such item of Equipment is at the time
in the possession of Lessee), the falsity of any non-tax representation or
warranty of Lessee or Lessee's failure to comply with the terms of the Lease
during the Lease Term. The foregoing indemnity shall cover, without limitation,
(i) any Claim in connection with a design or other defect (latent or patent) in
any item of Equipment, (ii) any Claim for infringement of any patent, copyright,
trademark or other intellectual property right, or (iii) any Claim for
negligence or strict or absolute liability in tort; provided, however, that
Lessee shall not indemnify any Indemnified Person for any liability to the
extent it results from such Indemnified Person's gross negligence or willful
misconduct.

        "Claim" means all liabilities, losses, damages, actions, suits, demands,
claims of any kind and nature (including, without limitation, claims relating to
environmental discharge, cleanup or compliance), and all costs and expenses
whatsoever to the extent they may be incurred or suffered by an Indemnified
Person in connection therewith (including, without limitation, reasonable
attorneys' fees and expenses), fines, penalties (and other charges of applicable
governmental authorities), licensing fees relating to any item of Equipment,
damage to or loss of use of property (including, without limitation,
consequential or special damages to third parties or damages to Lessee's
property), or bodily injury to or death of any person (including, without
limitation, any agent or employee of Lessee).

        "Indemnified Person" means Lessor (including without limitation, each of
its partners) and each of their respective successors, assigns, agents,
officers, directors, shareholders, partners, servants, agents and employees.

        Such indemnities shall continue in full force and effect,
notwithstanding the expiration or termination of this Lease. Upon Lessor's
written demand, Lessee shall assume and diligently conduct, at its sole cost and
expense, the entire defense of any Indemnified Person against any indemnified
Claim described in this SECTION 18. Lessor may not enter into any settlement or
other compromise with respect to any Claim covered by the indemnity set forth in
this SECTION 18 without Lessee's prior written consent, which shall not be
unreasonably withheld, conditioned or delayed, and if a claim is settled or
compromised without such consent, Lessee shall not be obligated to provide
indemnification under this SECTION 18. If any Indemnified Person obtains
recovery of any of the amounts that Lessee has paid to such Indemnified Person
pursuant to the indemnity set forth in this SECTION 18, then such Indemnified
Person shall promptly pay to Lessee the amount of such recovery. Lessee shall
not settle or compromise any Claim against or involving Lessor without first
obtaining Lessor's written consent thereto, which consent shall not be
unreasonably withheld. Lessee shall give Lessor prompt notice of any occurrence,
event or condition in connection with which Lessor may be entitled to
indemnification hereunder. The provisions of this SECTION 18 are in addition to,
and not in limitation of, the provisions of SECTION 14(b).

        19. NOTICES. Any notices or demands required or permitted hereunder
shall be given to the parties in writing and by personal delivery, regular or
certified mail, facsimile or telegram at the address set forth in the Lease Line
Schedule or to such other address as the parties may hereafter substitute by
written notice given in the manner prescribed in this Section. Such notices or
demands shall be deemed given upon receipt in the case of personal delivery and
upon mailing or transmission in the case of mail, facsimile or telegram. Lessee
agrees to provide Lessor with thirty (30) days' prior written notice of (a) any
merger or consolidation with or into any other business organization, (b) any
sale, lease or other disposition of assets not in the ordinary course of
business, and (c) any other material change in Lessee's financial structure or
ownership.

                                       8.

<PAGE>   10

        20. CONFIDENTIALITY. By execution of this Lease, Lessor agrees that, in
addition to any other agreement regarding confidentiality executed by it, Lessor
will not provide or disclose to any third party any confidential information
relating to the Lease or obtained from time to time in connection with the
Lease, or relating to Lessee or its business, business prospects or affairs,
except (a) to its own directors, officers, employees, auditors, counsel and
other professional advisors and to its affiliates if Lessor reasonably
determines that any such party should have access to such information; (b) if
such information is generally available to the public; (c) if required or
appropriate in any report, statement or testimony submitted to any governmental
authority having or claiming to have jurisdiction over Lessor; (d) if required
or appropriate in response to any summons or subpoena or in connection with any
litigation, to the extent permitted or deemed advisable by counsel; (e) to
comply with any requirement or law applicable to Lessor; (f) to the extent
necessary in connection with the exercise of any right or remedy under the
Lease; (g) to any participant or assignee of Lessor or any prospective
participant or assignee, provided that such participant or assignee or
prospective participant or assignee agrees in writing to be bound by this
SECTION 20 prior to disclosure, or (h) otherwise with the prior consent of
Lessee; provided, however, that any disclosure made in violation of the Lease
shall not affect the obligations of Lessee under the Lease. Confidential
information means any information, other than information readily available in
the public domain, that is identified to Lessor as confidential or proprietary
or is otherwise reasonably known to Lessor to be information that Lessee would
expect to remain confidential, including without limitation nonpublic financial
information, projections, business plans, customer lists, trade secrets and
other proprietary information. Lessor shall inform any third party to whom it
discloses confidential information that such information is subject to a
confidentiality agreement, provided, however, that failure to do so shall not
affect the obligation of Lessee hereunder and Lessor shall not be responsible
for any action/inaction of said third party.

        21. FURTHER ASSURANCES. Lessee will promptly execute and deliver to
Lessor such further reasonable documents and take such further reasonable action
as Lessor may request in order to more effectively carry out the intent and
purpose of this Lease or an assignment of Lessor's interest herein.

        22. MISCELLANEOUS. This Lease shall be binding upon and inure to the
benefit of the parties hereto, their permitted successors and assigns. Any
provision of the Lease which is unenforceable in any jurisdiction shall, as to
such jurisdiction, be ineffective to the extent of such prohibition or
unenforceability without invalidating the remaining provisions hereof; and any
such prohibition or unenforceability in any jurisdiction shall not invalidate or
render unenforceable such provision in any other jurisdiction; provided,
however, that to the extent that the provisions of any such applicable law can
be waived, they are waived by Lessee. Time is of the essence with respect to the
Lease. The captions set forth herein are for convenience only and shall not
define or limit any of the terms hereof. THIS LEASE SHALL IN ALL RESPECTS BE
GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF
CALIFORNIA, WITHOUT REFERENCE TO CONFLICT OF LAWS PRINCIPLES. LESSOR AND LESSEE
WAIVE ALL RIGHTS TO TRIAL BY JURY IN ANY LITIGATION ARISING FROM THIS LEASE.
THIS LEASE SHALL BECOME EFFECTIVE AND BINDING ON THE PARTIES, THEIR RESPECTIVE
SUCCESSORS AND PERMITTED ASSIGNS, AND SHALL BE DEEMED EXECUTED AND PERFORMED IN
THE STATE OF CALIFORNIA, WHEN THE RELATED EQUIPMENT SCHEDULE IS ACCEPTED BY
LESSOR. LESSEE CONSENTS TO THE NON-EXCLUSIVE JURISDICTION OF THE STATE COURTS OF
CALIFORNIA FOR THE RESOLUTION OF ANY DISPUTES HEREUNDER.

                                       9.

<PAGE>   11

        23. AMENDMENTS, MODIFICATIONS, WAIVERS. NONE OF THE PROVISIONS OF THIS
LEASE MAY BE AMENDED, MODIFIED OR WAIVED EXCEPT IN A WRITING SIGNED BY LESSOR
AND LESSEE.

INITIALS  PJR   (LESSEE)                   INITIALS    RDS    (LESSOR)
        -------                                     ---------

LESSEE:                                    LESSOR:

CHEMCONNECT, INC.                          LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By: /s/ Philip J. Ringo                    By: LIGHTHOUSE MANAGEMENT
   ---------------------------------           PARTNERS II, L.P.,
                                               its general partner

Name:  Phil J. Ringo
      ------------------------------       By: LIGHTHOUSE CAPITAL
Title: President and COO                       PARTNERS, INC.,
       -----------------------------           its general partner

                                           By: /s/ Richard D. Stubblefield
                                              ---------------------------------

                                           Name: Richard D. Stubblefield
                                                 ------------------------------

                                           Title: Managing Director
                                                  -----------------------------

                                       10

<PAGE>   12

                                    EXHIBIT A

     LEASE LINE SCHEDULE NO. 01, dated May 5, 1999 ("Lease Line Schedule"),
                                       to
  MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999 ("Master Lease"),
                                 by and between
      LIGHTHOUSE CAPITAL PARTNERS II, L.P., a Delaware limited partnership
      ("Lessor") and CHEMCONNECT, INC., a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

IN CONSIDERATION of the mutual covenants contained herein, the parties agree as
follows:

        LEASE LINE. The total Lessor's Cost of all units of Equipment under all
Equipment Schedules pursuant to this Lease Line Schedule shall not exceed
$700,000.00 (the "Commitment"). "LESSOR'S COST" means, with respect to a unit of
Equipment, the total cost to Lessor of purchasing such unit, as indicated on the
applicable Equipment Schedule. Lessor's obligation to fund Equipment Schedules
under the Commitment shall terminate on December 31, 1999 (the "Commitment
Termination Date"). The minimum Lessor's Cost for each Delivery & Acceptance
Certificate shall be $10,000.00.

        RENTAL FACTOR. The Rental Factor for each Equipment Schedule will be
2.98% of scheduled Lessor's Cost per month, payable monthly in advance. The
Rental Payment under a particular Equipment Schedule shall be an amount equal to
the product of (a) the Rental Factor and (b) the aggregate Lessor's Cost of
Equipment subject to such Equipment Schedule.

        INTERIM RENT. The daily Interim Rent factor shall be equal to 0.0208%
for each item of Equipment (the "Interim Rate"). The daily Interim Rent payment
shall be an amount equal to the product of (a) 0.0208%, and (b) the Lessor's
Cost for each item of Equipment.

        ADVANCE RENT. On the Commencement Date set forth in each Equipment
Schedule to this Lease Line Schedule, Lessee shall pay to Lessor advance rent
equal to the product of (a) the Rental Factor and (b) the aggregate Lessor's
Cost of Equipment subject to such Equipment Schedule ("Advance Rent"), to be
applied toward the last Rental Payment due from Lessee to Lessor under each
Equipment Schedule.

        EXPENSES. Lessee agrees to reimburse Lessor for up to One Thousand
Dollars ($1,000.00) of expenses incurred in connection with the negotiation and
documentation of this transaction, promptly upon receipt of an invoice.

        ELIGIBLE EQUIPMENT. All equipment to be financed under an Equipment
Schedule must be Eligible Equipment. "Eligible Equipment" means the following
types of equipment to the extent acceptable to Lessor:

        Various new and used computers, peripherals, analytical and test
equipment, laboratory equipment and furniture, office furniture and equipment,
software in an amount not to exceed Two Hundred Ten Thousand Dollars ($210,000),
and other equipment as mutually agreed to by Lessee and Lessor, together with
all replacements, parts, cables, repairs, additions and accessories incorporated
therein or affixed thereto and all operating manuals and manufacturer's
instructions (collectively hereinafter called the "Equipment"). Such
replacements, parts, cables, repairs, additions and accessories shall (whether
or not purchased by Lessor) be considered part of the Equipment for all purposes
and, when installed in or attached to the Equipment (unless otherwise agreed),
be or become the property of the Lessor. Except as otherwise specifically
provided or the context so requires, the term "Equipment" includes operating
system or other bundled software which is delivered on or with the Equipment and
which constitutes an accession that could not be removed upon Lease Termination
without adversely affecting the functionality of Equipment in which it is
installed or is included on the Equipment Schedules. Equipment that is older
than ninety (90) days will be valued at its net book value, provided however,
that with respect to the first Equipment Schedule under this Lease Line,
Equipment that is older than one hundred twenty (120) days will be valued at its
net book value.

        COMMENCEMENT DATE. The "Commencement Date" for each Equipment Schedule
shall be the first day of the calendar month following the Acceptance Date for
the items of Equipment subject to such Equipment Schedule.

                                       1
<PAGE>   13

        LEASE TERMINATION OPTIONS. Upon Lease Termination (as defined in the
Master Lease), Lessee will have, with respect to all but not less than all of
the Equipment governed by this Lease Line Schedule, the option to (a) purchase
the Equipment for the lesser of its then fair market value or twenty percent
(20%) of Lessor's Cost, (b) renew the Lease or (c) return the Equipment to
Lessor as provided in SECTION 6 of the Master Lease.

        ADVANCE NOTICE PERIOD. The "Advance Notice Period" shall be at least
ninety (90) days, but not more than 180 days, prior to Lease Termination (as
defined in the Master Lease) of Equipment Schedule No. 01 to this Lease Line
Schedule.

        AUTOMATIC EXTENSION PERIOD. The "Automatic Extension Period" shall equal
three (3) months and affects each Equipment Schedule under this Lease Line
Schedule.

        INSURANCE. The amount of commercial general liability insurance (other
than products liability coverage and completed operations insurance) required
under the Master Lease shall be at least $2,000,000 per occurrence. The amount
of the products liability and completed operations insurance under the Master
Lease shall be at least $2,000,000 per occurrence.

        FINANCIAL STATEMENTS. Lessee shall deliver to Lessor: (a) as soon as
available, but in any event within twenty (20) days after the end of each month,
a company prepared balance sheet, income statement and cash flow statement
covering Lessee's operations during such period, certified by an officer of
Lessee reasonably acceptable to Lessor; (b) as soon as available, but in any
event within ninety (90) days after the end of Lessee's fiscal year, audited
financial statements of Lessee prepared in accordance with generally accepted
accounting principles, consistently applied, together with an unqualified
opinion (other than a going concern qualification) on such financial statements
of an independent certified public accounting firm reasonably acceptable to
Lessor; (c) promptly upon becoming available, copies of all statements, reports,
budgets, sales projections, operating plans and notices sent or made available
generally by Lessee to its security holders; (d) immediately upon receipt of
notice thereof, a report of any material legal actions pending or threatened
against Lessee; and (e) such other financial information as Lessor may
reasonably request from time to time.

        MAINTENANCE SERVICE CONTRACTS. Lessee shall obtain and keep in effect at
all times during the Lease Term (and any renewal or extension thereof),
maintenance service contracts covering any Equipment with (i) a Lessor's Cost in
excess of $10,000 and/or (ii) Equipment for which maintenance service contracts
are customarily available with the Equipment supplier or with suppliers of
maintenance services approved by Lessor, such approval not to be unreasonably
withheld.

        INSTALLATION, HANDLING AND DELIVERY CHARGES. Any handling and delivery
charge to cover all Equipment transportation, rigging, drayage, packing,
installation and handling to and from vendor's plant and upon return to Lessor's
designated location shall be paid by Lessee.

        MISCELLANEOUS TAXES. Without limitation of the provisions of the Master
Lease, Lessee agrees to pay and to indemnify Lessor for any sales or use tax and
any property tax in connection with the sale, lease or use of the Equipment.

        LATE FEE. Lessee shall pay a late charge on any rent payments or other
sums due hereunder which are more than ten (10) days past due, in an amount
equal to 2% of the past due amount, payable on demand.

        DEFAULT RATE. The Default Rate of interest on late payments shall be
eighteen percent (18%) per annum.

        NOTICES. All notices shall be addressed as follows:

        IF TO LESSOR:                            IF TO LESSEE:

        Lighthouse Capital Partners II, L.P.     ChemConnect, Inc.
        100 Drake's Landing, Suite 260           44 Montgomery Street, Suite 250
        Greenbrae, CA 94904-3121                 San Francisco, CA 94104
        Attn.:  Contract Administration          Attn.:  Chief Financial Officer
        Phone: (415) 925-3370                    Phone: (415) 364.3300
        Fax: (415) 925-3387                      Fax: (415) 646-0010

                                       2
<PAGE>   14

        CONDITIONS TO THE FIRST EQUIPMENT SCHEDULE. On or prior to the date of
execution of the first Equipment Schedule under this Lease Line Schedule, Lessor
shall have received in form and substance satisfactory to Lessor, each of the
following:

        1.      A Warrant substantially in the form of EXHIBIT H to the Master
                Lease.

        2.      Copies, certified by the Secretary or Assistant Secretary or
                Chief Financial Officer of Lessee, of: (i) the Articles of
                Incorporation and By-Laws of Lessee (as amended to the date of
                the Lease) and (ii) the resolutions adopted by Lessee's board of
                directors authorizing the execution and delivery of this Lease,
                the Lease Line Schedule, the Equipment Schedules, the Warrant
                and the other documents referred in this Lease Line Schedule and
                the performance by Lessee of its obligations in such documents.

        3.      A Good Standing Certificate (including franchise tax status)
                with respect to Lessee from Lessee's state of incorporation,
                dated a date reasonably close to the date of acceptance of the
                Lease by Lessor.

        4.      A Software Rider substantially in the form of ANNEX B to this
                Lease Line Schedule.

        5.      Evidence of the insurance coverage required by SECTION 8 of the
                Master Lease.

        6.      All necessary consents of shareholders and other third parties
                with respect to the subject matter of the Master Lease, the
                Lease Line Schedule, the Equipment Schedules and the Warrant.

        CONDITIONS TO ALL FUNDINGS UNDER ALL EQUIPMENT SCHEDULES. On or prior to
each funding under each Equipment Schedule under this Lease Line Schedule, each
of the following conditions shall have been satisfied:

        1.      No Event of Default or event which, with notice or lapse of time
                or both, would become an Event of Default, has occurred and is
                continuing.

        2.      Lessor shall have received a Software Licenses Assignment
                Agreement in substantially the form of ANNEX B-1 to this Lease
                Line Schedule with respect to each Vendor of software to be
                financed under this Lease Line Schedule.

        3.      Lessor shall have received all necessary or desirable estoppel
                certificates and UCC filings, releases or terminations.

        4.      Lessor shall have used its best efforts to obtain a landlord
                waiver and consent in substantially the form of EXHIBIT E to the
                Master Lease with respect to each equipment location.

        5.      There shall not have occurred (i) any material adverse change to
                the general affairs, management, results of operations,
                condition (financial or otherwise) or prospects of Lessee,
                whether or not arising from transactions in the ordinary course
                of business, or (ii) any material adverse deviation by Lessee
                from the business plan of Lessee presented to and not
                disapproved by Lessor, since the date of the Master Lease.

        6.      Lessee shall have delivered to Lessor an Equipment Schedule
                covering the appropriate funding period.

        7.      Lessee shall have delivered to Lessor (i) in the case of a
                sale-leaseback, original vendor invoices, copies of canceled
                checks or other proof of payment, a Bill of Sale, a Delivery and
                Acceptance Certificate, and any UCC filings or other notices
                deemed necessary or desirable in connection with the
                sale-leaseback or (ii) at Lessor's request, in the case of a
                purchase of new equipment in excess of $50,000 from an equipment
                vendor, a Purchase Order and Invoice Assignment and a Delivery
                and Acceptance Certificate.

        8.      Payment of the Advance Rent.

                                       3.
<PAGE>   15

        9.      All terms and conditions in the Equipment Schedule shall have
                been satisfied by the Acceptance Date for the Equipment under
                such Equipment Schedule.

               All other documents as Lessor shall have reasonably requested.

LESSEE:                                    LESSOR:

CHEMCONNECT, INC.                          LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By:     EXHIBIT ONLY                       By: LIGHTHOUSE MANAGEMENT
   ---------------------------------           PARTNERS II, L.P.,
                                               its general partner
Name:  Phil J. Ringo
       -----------------------------
                                               By: LIGHTHOUSE CAPITAL
Title: President and COO                           PARTNERS, INC.,
       -----------------------------               its general partner

                                           By:
                                              ---------------------------------

                                           Name: Thomas Conneely
                                                 ------------------------------

                                           Title: Vice President, Operations
                                                  -----------------------------

ANNEX A     -   Stipulated Loss Value Table
ANNEX B     -   Software Rider
ANNEX B-1   -   Software License Assignment Agreement

                                       4.
<PAGE>   16

                                     ANNEX A

                           STIPULATED LOSS VALUE TABLE
                                       TO
                LEASE LINE SCHEDULE NO. 01, dated May 5, 1999, to
MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999 ("Master Lease"), by
and between LIGHTHOUSE CAPITAL PARTNERS II, L.P., a Delaware limited partnership
     ("Lessor"), and CHEMCONNECT, INC., a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

In the case of an Event of Loss, the Stipulated Loss Value for each item of
leased Equipment is the Lessor's Cost for the item multiplied by Stipulated Loss
Value Percentage for the Rent Payment Number following the month of the Event of
Loss.

<TABLE>
<CAPTION>
                                   Stipulated                                                  Stipulated
        Rent                         Loss                       Rent                              Loss
       Payment                       Value                     Payment                            Value
        Number                     Percentage                   Number                         Percentage
        ------                     ----------                   ------                         ----------
<S>                                <C>                         <C>                               <C>
          1                         111.88%                      19                               69.19%
          2                         109.78%                      20                               66.76%
          3                         106.95%                      21                               64.31%
          4                         104.54%                      22                               61.85%
          5                         102.11%                      23                               59.36%
          6                          98.78%                      24                               56.86%
          7                          96.64%                      25                               54.33%
          8                          94.47%                      26                               51.79%
          9                          92.28%                      27                               49.22%
         10                          90.07%                      28                               46.63%
         11                          87.84%                      29                               44.03%
         12                          85.59%                      30                               41.40%
         13                          83.31%                      31                               38.74%
         14                          81.09%                      32                               35.07%
         15                          78.69%                      33                               31.64%
         16                          76.35%                      34                               27.76%
         17                          73.99%                      35                               23.88%
         18                          71.60%                      36 and thereafter                20.00%
</TABLE>

Lessee: _______________                           Lessor:  _______________

                                      16.
<PAGE>   17

                                     ANNEX B

                                 SOFTWARE RIDER

        THIS SOFTWARE RIDER (this "Rider") is made a part of Lease Line Schedule
No. 01 (the ("Lease Line Schedule") dated May 5, 1999, by and between LIGHTHOUSE
CAPITAL PARTNERS II, L.P., a Delaware limited partnership ("Lessor") and
CHEMCONNECT, INC., a Delaware corporation ("Lessee").

All capitalized terms used and not otherwise defined herein are defined in the
Lease Line Schedule.

        In the event any computer software (as described in any applicable
Equipment Schedule and collectively with all manuals, updates, revisions,
program and data files, and documentation relating thereto or used or usable in
connection therewith, the "Software"), is purchased or licensed pursuant to the
Lease Line Schedule, then, in addition to all other terms and conditions of the
Master Lease and the Lease Line Schedule, all of which are incorporated herein
by this reference:

        1. SOFTWARE AS GENERAL INTANGIBLES. All Software shall be "Equipment" as
defined under the Lease Line Schedule. Lessee hereby grants to Lessor as
collateral security for Lessee's payment and performance of all Lessee's
obligations of payment and performance under this Rider, the Lease Line
Schedule, the Master Lease, and every other present or future Equipment Schedule
or other agreement between Lessee and Lessor, a security interest in all of its
right, title and interest in and to the Software, including without limitation
general intangibles, licenses, and intellectual property rights with respect
thereto, but excluding all licenses and other agreements that by law or by the
terms thereof may not be assigned by Lessee or may only be assigned by Lessee
with the consent of the other party to such license or other agreement, and all
substitutions, modifications, replacements, additions, accessions, proceeds, and
products of, to, or for any of the foregoing.

        2. EXCLUSION OF WARRANTIES. Without limiting the generality of all
exclusions of warranty set forth in the Lease Line Schedule and Master Lease,
Lessor makes no and specifically excludes any representation or warranty
relating to any Software, including without limitation any warranty of title,
validity or enforceability of license, noninfringement, availability or quality
of vendor support, or fitness for any particular purpose.

        3. LICENSE ASSIGNMENT AGREEMENT. Lessee will use its best efforts to
obtain a License Assignment Agreement in form and substance satisfactory to
Lessor and as set forth on EXHIBIT 1 hereto (the "Software License Assignment
Agreement")prior to the advance by Lessor of any funds to any party with respect
to the Software. Breach by Lessee of any term or condition of any license
agreement governing the right to use any Software shall be an Event of Default
under SECTION 16(ii) of the Master Lease if such breach is likely to have a
material adverse effect on the Equipment or Lessor's rights under the Lease Line
Schedule, Master Lease or any other documents relating to the lease of the
Equipment to Lessee.

        4. APPLICABILITY OF LEASE. The Master Lease, Lease Line Schedule,
Equipment Schedule, Software License Assignment Agreement, and this Rider, and
all documents entered into in connection therewith, govern Lessee's obligations
of payment and performance to Lessor with respect to the Software, whether or
not the Software represents goods capable of being leased pursuant to the UCC.

        5. LICENSE PERFORMANCE. Lessee agrees that in addition to Lessor's
remedies following an Event of Default, Lessor may upon notice to Lessee
requiring the same cause Lessee to cease all use of the Software and to assemble
and deliver to Lessor the same in electronic or other form. Lessee shall remit
to Lessor upon demand any amounts due and payable with respect to the licensing
of any Software or the assignment thereof. Lessee agrees that monetary damages
are not a sufficient remedy and will not adequately compensate Lessor for
Lessee's breach of this Section, and that Lessor shall be entitled to seek
specific performance or other injunctive or equitable relief.

                                      17.
<PAGE>   18

        6. INTEGRATION. This Rider represents the entirety of the understanding
between the parties with respect to its subject matter, and may only be modified
by a written instrument signed by the party to be charged. All rights and
remedies of Lessor herein are in addition to, and not in limitation of, the
rights and remedies of Lessor under the Lease.

LESSEE:                                   LESSOR:

CHEMCONNECT, INC.                         LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By:   EXHIBIT ONLY                        By: LIGHTHOUSE MANAGEMENT
   ---------------------------------          PARTNERS II, L.P.,
                                              its general partner
Name: Phil J. Ringo
      ------------------------------      By: LIGHTHOUSE CAPITAL PARTNERS, INC.,
Title: President and COO                      its general partner
       -----------------------------

                                          By:
                                              ---------------------------------

                                          Name: Thomas Conneely
                                                -------------------------------

                                          Title: Vice President, Operations
                                                 ------------------------------

                                      18.
<PAGE>   19

                                    ANNEX B-1
                                    EXHIBIT 1
                      SOFTWARE LICENSE ASSIGNMENT AGREEMENT

        This SOFTWARE LICENSE ASSIGNMENT AGREEMENT (this "Agreement") is entered
into May 5, 1999, by and between ______________________ ("Vendor"), LIGHTHOUSE
CAPITAL PARTNERS II, L.P., a Delaware limited partnership ("Lessor") and
CHEMCONNECT, INC., a Delaware corporation ("Lessee"), with respect to certain
items of computer software purchased or licensed from Vendor as more
specifically described in attachments hereto (the "Software") in connection with
that certain Equipment Schedule No. 01 between Lessee and Lessor (collectively
with all documents entered into in connection therewith, the "Lease") dated May
5, 1999.

        1. ACKNOWLEDGMENT OF LICENSE. The parties acknowledge that the right to
use the Software is being acquired pursuant to a software license agreement (the
"License") between Vendor and Lessee, and agree as follows:

           (a) Lessee reaffirms all of its rights and obligations under the
License and under the Lease. Lessor is not a party to the License, but is an
express third party beneficiary thereof.

           (b) Lessee assigns to Lessor all of its rights and benefits, but
Lessee retains all the obligations and burdens, under the License. Vendor
consents to such assignment.

           (c) Lessor sublicenses back to Lessee, expiring once there has been
an Event of Default under the Lease, the rights and benefits under the License.

        2. ASSIGNMENT. Lessor may upon notice to Vendor succeed to all of
Lessee's right, title and interest in and to the License, and may sell or assign
the same to any person, without the imposition of any transfer fee payable to
Vendor, effective upon such person's execution of the License, who shall upon
such execution succeed to the obligations and burdens under such license.

        3. NO COMMITMENT. This is not a commitment by Lessor to purchase or
finance any other items of software or hardware other than the Software.

        4. INTEGRATION. This Agreement represents the entirety of the
understanding between the parties with respect to its subject matter, and may
only be modified by a written instrument signed by the party to be charged.

VENDOR                                     LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By:                                        By: LIGHTHOUSE MANAGEMENT
   ---------------------------------           PARTNERS II, L.P.,
                                               its general partner

By:
   ---------------------------------           By: LIGHTHOUSE CAPITAL
                                                   PARTNERS, INC.,
Title:                                             its general partner
      ------------------------------

CHEMCONNECT, INC.                              By:
                                                  -----------------------------

By: EXHIBIT ONLY                               Name: Thomas Conneely
    --------------------------------                 --------------------------

Name: Phil J. Ringo                            Title: Vice President, Operations
      ------------------------------                  -------------------------

Title: President and COO
       -----------------------------

                                      19.
<PAGE>   20

                                    EXHIBIT B

     EQUIPMENT SCHEDULE NO. 01, dated May 5, 1999 ("Equipment Schedule") to
    LEASE LINE SCHEDULE NO. 01, dated May 5, 1999 ("Lease Line Schedule"), to
  MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999 ("Master Lease"),
       by and between LIGHTHOUSE CAPITAL PARTNERS II, L.P. ("Lessor") and
             CHEMCONNECT, INC., a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

Total Lessor's Cost:     The total Lessor's Cost under this Equipment Schedule
                         shall be an amount equal to the sum of the Lessor's
                         Cost under each Delivery and Acceptance Certificate
                         executed by Lessee between the date of this Equipment
                         Schedule and ten days prior to the Commencement Date,
                         and which refers to this Equipment Schedule.

Lease Term:              36 Months

Commencement Date:       June 1, 1999

Interim Rent:            On or about the Commencement Date, Lessor shall send
                         Lessee a "Summary of Equipment Schedule" in the form of
                         ANNEX A hereto, specifying, among other things, the
                         applicable Interim Rent; provided, however, that any
                         failure by Lessor to send Lessee a Summary of Equipment
                         Schedule shall not relieve Lessee of its obligation to
                         pay rent hereunder.

Rental Factor:           The Rental Factor shall be set forth in the Summary of
                         Equipment Schedule.

Rental Payments:         The amount of the monthly Rental Payments, calculated
                         in accordance with the Lease Line Schedule and payable
                         monthly in advance, shall be set forth in the Summary
                         of Equipment Schedule. Payments shall be made to
                         Lessor's address set forth in the Lease Line Schedule.

Rental Payment Dates:    First day of each calendar month.

Equipment Description:   The Equipment shall be described in each Delivery and
                         Acceptance Certificate executed by Lessee between the
                         date of this Equipment Schedule and the Commencement
                         Date, and which refers to this Equipment Schedule.
                         Delivery and Acceptance Certificates under this
                         Equipment Schedule must be received by Lessor no later
                         than ten business days prior to the Commencement Date.

Equipment Location:      44 Montgomery Street, Suite 250, San Francisco,
                         California 94104

Terms and Conditions:    The terms and conditions of the above-referenced Master
                         Lease and Lease Line Schedule are incorporated herein.
                         In addition, the following attachments apply to this
                         Equipment Schedule only: None.

                                       1.
<PAGE>   21

No Default:              No Event of Default or event which, with notice or
                         lapse of time or both, would become an Event of
                         Default, has occurred and is continuing.

LESSEE:                                    LESSOR:

CHEMCONNECT, INC.                          LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By: EXHIBIT ONLY                           By: LIGHTHOUSE MANAGEMENT
    --------------------------------           PARTNERS II, L.P.,
                                               its general partner
Name: Phil J. Ringo
      ------------------------------       By: LIGHTHOUSE CAPITAL
                                               its general partner
Title: President and COO
       -----------------------------

                                               By:
                                                  -----------------------------

                                               Name: Thomas Conneely
                                                     --------------------------

                                               Title: Vice President, Operations
                                                      -------------------------

                                       2.

<PAGE>   22

                                     ANNEX A

                     SUMMARY OF EQUIPMENT SCHEDULE NO. 01 to
                LEASE LINE SCHEDULE NO. 01, dated May 5, 1999, to
           MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999
                         ("Master Lease") by and between
              LIGHTHOUSE CAPITAL PARTNERS II, L.P. ("Lessor") and
              CHEMCONNECT, INC., a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

Total Lessor's Cost:                           $__________

Total Interim Rent:                            $__________

Rental Factor:                                 2.98%

Rental Payments:                               36 payments of $__________
                                               each, payable monthly in advance

Amount of Advance Rent applied to this
Equipment Schedule:                            $__________

                                           LIGHTHOUSE CAPITAL PARTNERS II, L.P.

                                           By: LIGHTHOUSE MANAGEMENT
                                               PARTNERS II, L.P.,
                                               its general partner

                                               By: LIGHTHOUSE CAPITAL
                                                   PARTNERS, INC.,
                                                   its general partner

                                               By: EXHIBIT ONLY
                                                   ----------------------------

                                               Name: Thomas Conneely
                                                     --------------------------

                                               Title: Vice President, Operations
                                                      -------------------------

                                       3.

<PAGE>   23

                                    EXHIBIT C

                       DELIVERY AND ACCEPTANCE CERTIFICATE
                                      UNDER
                EQUIPMENT SCHEDULE NO. 01, dated May 5, 1999, to
                LEASE LINE SCHEDULE NO. 01, dated May 5, 1999, to
           MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999
                                 by and between
     LIGHTHOUSE CAPITAL PARTNERS II, L.P. ("Lessor") and CHEMCONNECT, INC.,
                       a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

         Installation Address:             44 Montgomery Street, Suite 250,
                                           San Francisco, CA 94104

         Lessor's Cost:                    $__________

         Commencement Date:                June 1, 1999

         Equipment Description:

<TABLE>
<CAPTION>
      Qty               Model & Description        Original Unit Purchase Price           Lessor's Cost
      ---               -------------------        ----------------------------           -------------
<S>                        <C>                    <C>                                     <C>
                            SEE ANNEX A
</TABLE>

        Lessee acknowledges receipt and acceptance of the Equipment listed in
ANNEX A and agrees the Equipment has been delivered and is ready for use under
the terms of the above-referenced Master Equipment Lease Agreement, Lease Line
Schedule, and Equipment Schedule, the terms and conditions of which are
incorporated herein, including, without limitation, the obligation to pay
Interim Rent and to make Rental Payments.

Acceptance Date: __________, 1999

LESSEE:

CHEMCONNECT, INC.

By: EXHIBIT ONLY
    --------------------------------

Name: Phil J. Ringo
      ------------------------------

Title: President and COO
       -----------------------------

ANNEX A

                                       1.

<PAGE>   24

                                     ANNEX A

                              EQUIPMENT DESCRIPTION

<TABLE>
<CAPTION>
      Qty               Model & Description        Original Unit Purchase Price           Lessor's Cost
      ---               -------------------        ----------------------------           -------------
<S>                        <C>                    <C>                                     <C>
                            SEE ANNEX A
</TABLE>

                                       2.

<PAGE>   25

                                    ANNEX B-1

                                  BILL OF SALE

        For and in consideration of the sum of One Dollar ($1.00) and other
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, CHEMCONNECT, INC. (herein "Seller"), does hereby sell, grant,
transfer and deliver all right, title and interest in and to the equipment
further described on ANNEX A hereto (herein the "Equipment"), together with all
warranties, guarantees or other similar rights with respect to the Equipment
("Equipment Warranties") unto LIGHTHOUSE CAPITAL PARTNERS II, L.P. (herein
"Purchaser") and to its successors and assigns to have and to hold said
Equipment and the Equipment Warranties forever. Except for the Equipment
Warranties, the Equipment is sold "as is" and "where is" and the description of
the Equipment is for the sole purpose of identifying it and is not part of the
basis of the bargain.

        Seller represents and warrants that it holds all right, title and
interest in and to the Equipment being transferred free and clear of all liens
and encumbrances of any kind and Seller does for itself, its successors and
assigns covenant and agree with Purchaser, its successors and assigns, to
warrant and defend the sale of the Equipment and the transfer of the Equipment
Warranties unto Purchaser, its successors and assigns against all and every
person and persons whomsoever claiming or laying claim to the same, except for
any defects in title or liens or encumbrances in or to the Equipment arising
solely by reason of Purchaser's own acts.

        THE WARRANTY SET FORTH IN THE FOREGOING PARAGRAPH AND THE EQUIPMENT
WARRANTIES ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES OF SELLER, WHETHER
WRITTEN, ORAL OR IMPLIED, AND SELLER SHALL NOT, BY VIRTUE OF HAVING SOLD THE
EQUIPMENT HEREWITH, BE DEEMED TO HAVE MADE ANY REPRESENTATION OF WARRANTY AS TO
THE MERCHANTABILITY, FITNESS, DESIGN OR CONDITION OF, OR AS TO THE QUALITY OF
THE MATERIAL OR WORKMANSHIP IN, THE EQUIPMENT.

        IN WITNESS WHEREOF, we have set our hand and seal this _________ day of
May, 1999.

LESSEE:

CHEMCONNECT, INC.

By: EXHIBIT ONLY
   ---------------------------------

Name: Phil J. Ringo
      ------------------------------

Title: President and COO
       -----------------------------

                                      1
<PAGE>   26

                                    ANNEX B-2

        THIS PURCHASE ORDER ASSIGNMENT, dated as of _____, 199____ (this
"Assignment"), between CHEMCONNECT, INC. ("Assignor") and LIGHTHOUSE CAPITAL
PARTNERS II, L.P. ("Assignee").

                              W I T N E S S E T H :

        WHEREAS, Assignor has submitted its Purchase Orders and Invoices listed
in SCHEDULE 1 hereto (collectively, the "Purchase Orders"), to
___________________ (the "Vendor") concerning certain units of equipment (the
"Units") listed in SCHEDULE 1 hereto to be subject to a Master Equipment Lease
Agreement No. 219, dated as of May 5, 1999 (the "Master Lease"), between
Assignor and Assignee (all terms used but not otherwise defined herein shall
have the meaning given to them in the Master Lease):

        NOW, THEREFORE, in consideration of the premises and the mutual
covenants herein contained, the parties hereto agree as follows:

        1. Assignor does hereby sell, assign, transfer and set over unto
Assignee, all of the Assignor's rights to and interests in the Purchase Orders
as and to the extent that the same relates to the Units. The assignment herein
shall include, without limitation, the right of Assignee to purchase the Units
pursuant to the Purchase Orders and to take title to the Units, all claims for
damages in respect of the Units arising as a result of any default by Vendor
under the Purchase Orders, together with any and all rights of Assignor to
compel performance of the terms of the Purchase Orders in respect of the Units.

        2. The exercise by Assignee of any of the rights assigned hereunder
shall not release Assignor from any of its duties or obligations to Vendor under
the Purchase Orders except to the extent that such exercise by Assignee shall
constitute performance of such duties and obligations.

        3. Upon satisfaction of the conditions set forth in the applicable Lease
Line Schedule to the Master Lease with respect to the Units, Assignee shall
purchase such Unit by paying or causing to be paid, by check mailed or delivered
to Vendor, on such date or thereafter as permitted by Vendor, an amount equal to
the purchase price of the Unit, as such amount may be adjusted in accordance
with the terms of the Purchase Orders and reflected on invoices prepared by
Vendor to Assignee on or before the date of delivery and acceptance of the Unit.

        4. Assignor agrees that it will, at any time and from time to time, upon
the written consent of Assignee, promptly and duly exercise and deliver any and
all such further instruments and documents and take such further action as
Assignee may reasonably request in order that Assignee may obtain the full
benefits of this Agreement and of the rights and powers herein granted.

        5. Assignor represents and warrants that the Purchase Orders are in full
force and effect and that Assignor is not in default under any of them. Assignor
further represents and warrants that Assignor has not assigned or pledged, and
so long as this Assignment shall remain in effect, will not assign or pledge,
the whole or any part of the rights hereby assigned or any of its rights with
respect to the Units under the Purchase Orders to anyone other than Assignee.

                                       1.
<PAGE>   27

        IN WITNESS WHEREOF, the parties hereto have caused this Purchase Order
Assignment to be duly executed as of the day and year first above written.

LESSEE:                                    LESSOR:

CHEMCONNECT, INC.                          LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By: EXHIBIT ONLY                           By: LIGHTHOUSE MANAGEMENT
   -----------------------------               PARTNERS II, L.P.,
                                               its general partner
Name: Phil J. Ringo
     ---------------------------               By: LIGHTHOUSE CAPITAL
Title: President and COO                           PARTNERS, INC.,
      --------------------------                   its general partner

                                               By:
                                                  -----------------------------
                                               Name: Thomas Conneely
                                                     --------------------------
                                               Title: Vice President, Operations
                                                      -------------------------

Acknowledged and Consented to this ____________ day of __________, 199___.

VENDOR:

By:
   ---------------------------------

Name:
     -------------------------------

Title:
      ------------------------------

                                       2.
<PAGE>   28

                                    EXHIBIT D

                               NOTICE OF ELECTION

                                      under

                LEASE LINE SCHEDULE NO. 01, dated May 5, 1999, to
           MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999
      ("Master Lease") by and between LIGHTHOUSE CAPITAL PARTNERS II, L.P.
        ("Lessor") and CHEMCONNECT, a California corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

        1. Pursuant to SECTION 4(d) of the Master Lease, Lessee hereby elects
the Lease Termination Option indicated below for the above Lease Line Schedule.

                Option Election            (check one)

                Purchase                   ______________________
                Renew                      ______________________
                Return                     ______________________

        2. If the renewal option is selected, then Lessee and Lessor must agree
upon the rental period and rental amount. If Lessee and Lessor are unable to
agree upon the terms of renewal, then this Notice of Election shall be deemed
invalid and a new Notice of Election must be submitted by Lessee.

Dated: __________________

                                           CHEMCONNECT

                                           By: EXHIBIT ONLY
                                               --------------------------------

                                           Name: Phil J. Ringo
                                                 ------------------------------

                                           Title: President and COO
                                                  -----------------------------

<PAGE>   29

                                    EXHIBIT E

RECORDING REQUESTED BY
AND WHEN RECORDED RETURN TO:
Lighthouse Capital Partners II, L.P.
100 Drake's Landing Road, Suite 260
Greenbrae, CA  94904-3121
Attn.: Contract Administration

________________________________________________________________________________
                     CONSENT TO REMOVAL OF PERSONAL PROPERTY

KNOW ALL PERSONS BY THESE PRESENTS:

        (a) The undersigned has an interest as owner and landlord in that
certain real property (the "Real Property") in the County of Santa Clara, State
of California, described as: SEE EXHIBIT 1 ATTACHED HERETO FOR FULL LEGAL
DESCRIPTION, and commonly known as 44 Montgomery Street, Suite 250, San
Francisco, California 94104 (Parcel No. ).

        (b) CHEMCONNECT, INC., a Delaware corporation ("Lessee"), has entered
into or will enter into a Master Equipment Lease Agreement with LIGHTHOUSE
CAPITAL PARTNERS II, L.P. ("Lessor") (as amended and supplemented from time to
time, the "Lease Agreement").

        (c) Lessor, as a condition to entering into the Lease Agreement,
requires that the undersigned consent to the removal by Lessor of the equipment
and other assets covered by the Lease Agreement (hereinafter the "Equipment")
from the Real Property, no matter how it is affixed thereto, and to the other
matters set forth below.

NOW, THEREFORE, for good and sufficient consideration, receipt of which is
hereby acknowledged, the undersigned consents to the placing of the Equipment on
the Real Property, and agrees with Lessor as follows:

        1. The undersigned waives and releases each and every right which
undersigned now has, under the laws of the State of California or by virtue of
the lease for the Real Property now in effect, to levy or distrain upon for
rent, in arrears, in advance or both, or to claim or assert title to the
Equipment that is already on said Real Property, or may hereafter be delivered
or installed thereon.

        2. The Equipment shall be considered to be personal property and shall
not be considered part of the Real Property regardless of whether or by what
means it is or may become attached or affixed to the Real Property.

        3. The undersigned will permit Lessor, or its agent or representative,
to enter upon the Real Property for the purpose of exercising any right it may
have under the terms of the Lease Agreement or otherwise, including, without
limitation, the right to remove the Equipment; provided, however, that if
Lessor, in removing the Equipment damages any improvements of the undersigned on
the Real Property, Lessor will, at its expense, cause same to be repaired,
normal wear and tear excepted. The right of Lessor to enter the Real Property
shall not terminate until thirty (30) days after Lessor receives written notice
from the undersigned of the termination of the Lease.

        4. This agreement shall be binding upon the heirs, successors and
assigns of the undersigned and shall inure to the benefit of Lessor and its
successors and assigns.

IN WITNESS WHEREOF, the undersigned has executed this instrument this ____ day
of __________________, 1999.

LANDLORD                                   Notarial Acknowledgment required.

By: EXHIBIT ONLY
   ---------------------------------
Name:
     -------------------------------
Title:
      ------------------------------

                  ATTACH LEGAL DESCRIPTION OF THE REAL PROPERTY

<PAGE>   30

                                    EXHIBIT F

                  ACKNOWLEDGMENT FROM USER OF MOBILE EQUIPMENT

                                      UNDER

     EQUIPMENT SCHEDULE NO. 01, dated May 5, 1999 ("Equipment Schedule"), to
    LEASE LINE SCHEDULE NO. 01, dated May 5, 1999 ("Lease Line Schedule"), to
  MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999 ("Master Lease")
       by and between LIGHTHOUSE CAPITAL PARTNERS II, L.P. ("Lessor") and
             CHEMCONNECT, INC., a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

        1. The undersigned acknowledges and agrees that:

           (a) the Equipment listed below is owned by Lessor and is subject to
the terms and conditions of the Master Lease, Lease Line Schedule and Equipment
Schedule; and

           (b) upon the occurrence and continuance of an Event of Default under
the Master Lease, Lessor may, among other things, take possession of the
Equipment and upon request the undersigned agrees to make such Equipment
available to Lessor.

        2. The undersigned's address is:

            ________________________
            ________________________
            ________________________
            Phone:__________________
            Fax:____________________

<TABLE>
    QTY                    MODEL & DESCRIPTION                     SERIAL NUMBER                       LCP ASSET TAG NUMBER
    ---                    -------------------                     -------------                       --------------------
<S>                       <C>                                     <C>                                  <C>
     1
</TABLE>

        IN WITNESS WHEREOF, the undersigned has executed this Acknowledgment as
of the date written below.

Dated: _______________, 1999

                                               MOBILE EQUIPMENT USER

                                               By: EXHIBIT ONLY
                                                   ----------------------------

                                               Name:
                                                     --------------------------

                                               Title:
                                                     --------------------------

<PAGE>   31

                                    EXHIBIT G

                               OPINION OF COUNSEL
                                CHEMCONNECT, INC.

This requirement has been waived for all funding under Lease Line Schedule No.
01 to Master Equipment Lease Agreement No. 219.

<PAGE>   32

                                    EXHIBIT H

THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE "1933 ACT"), OR ANY APPLICABLE STATE SECURITIES LAWS, AND MAY NOT
BE SOLD OR TRANSFERRED UNLESS SUCH SALE OR TRANSFER IS IN ACCORDANCE WITH THE
REGISTRATION REQUIREMENTS OF SUCH ACT AND APPLICABLE LAWS OR SOME OTHER
EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF SUCH ACT AND APPLICABLE LAWS IS
AVAILABLE WITH RESPECT THERETO.

                        PREFERRED STOCK PURCHASE WARRANT

Warrant No. __________                                  Number of Shares: 21,539
                                                        Series B Preferred Stock

                                CHEMCONNECT, INC.

                           Void after April 30, 2006

        1. ISSUANCE. This Warrant is issued to LIGHTHOUSE CAPITAL PARTNERS II,
L.P. by CHEMCONNECT, INC., a Delaware corporation (hereinafter with its
successors called the "Company").

        2. PURCHASE PRICE; NUMBER OF SHARES. The registered holder of this
Warrant (the "Holder"), commencing on the date hereof, is entitled upon
surrender of this Warrant with the subscription form annexed hereto duly
executed, at the principal office of the Company, to purchase from the Company
the following securities (collectively, the "Shares") at a price per share of
$1.30 (the "Purchase Price"), 21,539 fully paid and nonassessable shares of
Series B Preferred Stock, $0.0001 par value, of the Company (the "Preferred
Stock"). Until such time as this Warrant is exercised in full or expires, the
Purchase Price and the securities issuable upon exercise of this Warrant are
subject to adjustment as hereinafter provided. The person or persons in whose
name or names any certificate representing shares of Preferred Stock is issued
hereunder shall be deemed to have become the holder of record of the shares
represented thereby as at the close of business on the date this Warrant is
exercised with respect to such shares, whether or not the transfer books of the
Company shall be closed.

        3. PAYMENT OF PURCHASE PRICE. The Purchase Price may be paid (i) in cash
or by check, (ii) by the surrender by the Holder to the Company of any
promissory notes or other obligations issued by the Company, with all such notes
and obligations so surrendered being credited against the Purchase Price in an
amount equal to the principal amount thereof plus accrued interest to the date
of surrender, or (iii) by any combination of the foregoing.

        4. NET ISSUE ELECTION. The Holder may elect to receive, without the
payment by the Holder of any additional consideration, shares of Preferred Stock
equal to the value of this Warrant or any portion hereof by the surrender of
this Warrant or such portion to the Company, with the net issue election notice
annexed hereto duly executed, at the principal office of the Company. Thereupon,
the Company shall issue to the Holder such number of fully paid and
nonassessable shares of Preferred Stock as is computed using the following
formula:

                                   X = Y (A-B)
                                       ------
                                          A

where: X = the number of shares of Preferred Stock to be issued to the Holder
           pursuant to this SECTION 4.

           Y = the number of shares of Preferred Stock covered by this Warrant
               in respect of which the net issue election is made pursuant to
               this SECTION 4.

           A = the Fair Market Value (defined below) of one share of Preferred
               Stock, as determined at the time the net issue election is made
               pursuant to this SECTION 4.

<PAGE>   33

           B = the Purchase Price in effect under this Warrant at the time the
               net issue election is made pursuant to this SECTION 4. "Fair
               Market Value" of a share of Preferred Stock (or Common Stock if
               the Preferred Stock has been automatically converted into Common
               Stock) as of a particular date (the "Determination Date") shall
               mean:

                (a) If the net issue election is made in connection with and
        contingent upon the closing of the sale of the Company's Common Stock to
        the public in a public offering pursuant to a Registration Statement
        under the Securities Act of 1933 ("1933 Act") (a "Public Offering"), and
        if the Company's Registration Statement relating to such Public Offering
        ("Registration Statement") has been declared effective by the Securities
        and Exchange Commission, then the initial "Price to Public" specified in
        the final prospectus with respect to such offering multiplied by the
        number of shares of Common Stock into which each share of Preferred
        Stock is then convertible.

                (b) If the net issue election is not made in connection with and
        contingent upon a Public Offering, then as follows:

                        (i) If traded on a securities exchange or the Nasdaq
                National Market, the fair market value of the Common Stock shall
                be deemed to be the average of the closing or last reported sale
                prices of the Common Stock on such exchange or market over the
                five day period ending five business days prior to the
                Determination Date, and the fair market value of the Preferred
                Stock shall be deemed to be such fair market value of the Common
                Stock multiplied by the number of shares of Common Stock into
                which each share of Preferred Stock is then convertible;

                        (ii) If otherwise traded in an over-the-counter market,
                the fair market value of the Common Stock shall be deemed to be
                the average of the closing ask prices of the Common Stock over
                the five day period ending five business days prior to the
                Determination Date, and the fair market value of the Preferred
                Stock shall be deemed to be such fair market value of the Common
                Stock multiplied by the number of shares of Common Stock into
                which each share of Preferred Stock is then convertible; and

                        (iii) If there is no public market for the Common Stock,
                then fair market value shall be determined in good faith by the
                Company's Board of Directors.

        5. PARTIAL EXERCISE. This Warrant may be exercised in part, and the
Holder shall be entitled to receive a new warrant, which shall be dated as of
the date of this Warrant, covering the number of shares in respect of which this
Warrant shall not have been exercised.

        6. FRACTIONAL SHARES. In no event shall any fractional share of
Preferred Stock be issued upon any exercise of this Warrant. If, upon exercise
of this Warrant in its entirety, the Holder would, except as provided in this
SECTION 6, be entitled to receive a fractional share of Preferred Stock, then
the Company shall pay in lieu thereof, the Fair Market Value of such fractional
share in cash.

        7. EXPIRATION DATE; AUTOMATIC EXERCISE. This Warrant shall expire at the
close of business on April 30, 2006, and shall be void thereafter.
Notwithstanding the foregoing, this Warrant shall automatically be deemed to be
exercised in full pursuant to the provisions of SECTION 4 hereof, without any
further action on behalf of the Holder, immediately prior to the time this
Warrant would otherwise expire pursuant to the preceding sentence.

        8. RESERVED SHARES; VALID ISSUANCE. The Company covenants that it will
at all times from and after the date hereof reserve and keep available such
number of its authorized shares of Preferred Stock and Common Stock, $0.0001 par
value, of the Company (the "Common Stock"), free from all preemptive or similar
rights therein, as will be sufficient to permit, respectively, the exercise of
this Warrant in full and the conversion into shares of Common Stock of all
shares of Preferred Stock receivable upon such exercise. The Company further
covenants that such shares as may be issued pursuant to such exercise and/or
conversion will, upon issuance, be duly

                                       2.
<PAGE>   34

        and validly issued, fully paid and nonassessable and free from all
taxes, liens and charges with respect to the issuance thereof.

        9. STOCK SPLITS AND DIVIDENDS. If after the date hereof the Company
shall subdivide the Preferred Stock, by split-up or otherwise, or combine the
Preferred Stock, or issue additional shares of Preferred Stock in payment of a
stock dividend on the Preferred Stock, the number of shares of Preferred Stock
issuable on the exercise of this Warrant shall forthwith be proportionately
increased in the case of a subdivision or stock dividend, or proportionately
decreased in the case of a combination, and the Purchase Price shall forthwith
be proportionately decreased in the case of a subdivision or stock dividend, or
proportionately increased in the case of a combination.

        10. NO STOCKHOLDER RIGHTS. Except as expressly provided in this Warrant,
prior to exercise of this Warrant, the Holder shall not be entitled to any
rights of a stockholder with respect to the Shares, including without limitation
the right to vote such Shares, receive dividends or other distributions thereon,
exercise preemptive rights or be notified of stockholder meetings, and such
Holder shall not be entitled to any notice or other communication concerning the
business or affairs of the Company, provided, however, that nothing in this
SECTION 10 shall limit the right of the Holder to be provided the notices
required under the Warrant.

        11. MERGERS AND RECLASSIFICATIONS. If after the date hereof the Company
shall enter into any Reorganization (as hereinafter defined), then, as a
condition of such Reorganization, lawful provisions shall be made, and duly
executed documents evidencing the same from the Company or its successor shall
be delivered to the Holder, so that the Holder shall thereafter have the right
to purchase, at a total price not to exceed that payable upon the exercise of
this Warrant in full, the kind and amount of shares of stock and other
securities and property receivable upon such Reorganization by a holder of the
number of shares of Preferred Stock which might have been purchased by the
Holder immediately prior to such Reorganization, and in any such case
appropriate provisions shall be made with respect to the rights and interest of
the Holder to the end that the provisions hereof (including without limitation,
provisions for the adjustment of the Purchase Price and the number of shares
issuable hereunder and the provisions relating to the net issue election) shall
thereafter be applicable in relation to any shares of stock or other securities
and property thereafter deliverable upon exercise hereof. For the purposes of
this SECTION 11, the term "Reorganization" shall mean and refer to (i) an
acquisition of the Company by another entity by means of a merger,
consolidation, or other transaction or series of related transactions resulting
in the exchange of the outstanding shares of the Company's capital stock such
that stockholders of the Company prior to such transaction own, directly or
indirectly, less than 50% of the voting power of the surviving entity, or (ii) a
sale or transfer of all or substantially all of the Company's asset to any other
person.

        12. CERTIFICATE OF ADJUSTMENT. Whenever the Purchase Price is adjusted,
as herein provided, the Company shall promptly deliver to the Holder a
certificate of the Company's chief financial officer setting forth the Purchase
Price after such adjustment and setting forth a brief statement of the facts
requiring such adjustment.

        13. NOTICES OF RECORD DATE, ETC. In the event of:

            (a) any taking by the Company of a record of the holders of any
class of securities for the purpose of determining the holders thereof who are
entitled to receive any dividend or other distribution, or any right to
subscribe for, purchase, sell or otherwise acquire or dispose of any shares of
stock of any class or any other securities or property, or to receive any other
right;

            (b) any reclassification of the capital stock of the Company,
capital reorganization of the Company, consolidation or merger involving the
Company, or sale or conveyance of all or substantially all of its assets; or

            (c) any voluntary or involuntary dissolution, liquidation or
winding-up of the Company;

then in each such event the Company will provide or cause to be provided to the
Holder a written notice thereof. Such notice shall be provided at least twenty
(20) business days prior to the date specified in such notice on which any such
action is to be taken.

                                       3.
<PAGE>   35

        14. REPRESENTATIONS, WARRANTIES AND COVENANTS. This Warrant is issued
and delivered by the Company and accepted by each Holder on the basis of the
following representations, warranties and covenants made by the Company:

            (a) The Company has all necessary authority to issue, execute and
deliver this Warrant and to perform its obligations hereunder. This Warrant has
been duly authorized issued, executed and delivered by the Company and is the
valid and binding obligation of the Company, enforceable in accordance with its
terms.

            (b) The shares of Preferred Stock issuable upon the exercise of this
Warrant have been duly authorized and reserved for issuance by the Company and,
when issued in accordance with the terms hereof, will be validly issued, fully
paid and nonassessable.

            (c) The issuance, execution and delivery of this Warrant do not, and
the issuance of the shares of Preferred Stock upon the exercise of this Warrant
in accordance with the terms hereof will not, (i) violate or contravene the
Certificate or by-laws, or to the Company's knowledge, any law, statute,
regulation, rule, judgment or order applicable to the Company, (ii) violate,
contravene or result in a breach or default under any contract, agreement or
instrument to which the Company is a party or by which the Company or any of its
assets are bound or (iii) require the consent or approval of or the filing of
any notice or registration with any person or entity.

            (d) As long as this Warrant is, or any shares of Preferred Stock
issued upon exercise of this Warrant or any shares of Common Stock issued upon
conversion of such shares of Preferred Stock are, issued and outstanding, the
Company will provide to the Holder the financial and other information described
in that certain Lease Line Schedule No. 01 to Master Equipment Lease Agreement
No. 219 between the Company and Lighthouse Capital Partners II, L.P. dated as
of May 5, 1999.

            (e) As of the date hereof, the authorized capital stock of the
Company consists of (i) 19,000,000 shares of Common Stock, none of which are
issued and outstanding and 21,539 shares are reserved for issuance upon the
exercise of this Warrant and the conversion of the Preferred Stock, (ii)
5,686,573 shares of Series A Preferred Stock, all of which are issued and
outstanding, and (iii) 4,130,000 shares of Series B Preferred Stock, of which
3,970,000 are issued and outstanding shares and 21,539 shares are reserved for
issuance upon exercise of this Warrant. Attached hereto as EXHIBIT C is a
capitalization table summarizing the capitalization of the Company, including,
without limitation, the current Conversion Price of the Series B Preferred
Stock.

        15. INVESTORS' RIGHTS AGREEMENT. The Company agrees that, upon the next
amendment of that certain Amended and Restated Investors' Rights Agreement by
and among the Company, the Investors and the Founders listed therein dated as of
December 17, 1998 (the "Investors' Rights Agreement"), it will use its best
efforts to effect such amendment so that the Holder shall be an Investor within
the meaning of such Investors' Rights Agreement.

        16. RIGHT OF FIRST REFUSAL. Subject to the terms and conditions
contained in this SECTION 16, the Company agrees that the holder of this Warrant
has the right of first refusal to purchase its pro rata portion of any New
Securities (as defined in SECTION 16(a) below) which the Company may, from time
to time, propose to sell and issue. A holder's pro rata portion for purposes of
this SECTION 16 is the ratio that (x) the sum of the number of shares of the
Company's Common Stock then issued or issuable to the holder (including upon
conversion of any Preferred Stock held by the holder and upon exercise of this
Warrant and conversion of the Shares issued thereupon) bears to (y) the sum of
the total number of shares of Company's Common Stock then outstanding, the
number of shares of the Company's Common Stock issuable upon conversion of the
Preferred Stock then outstanding, and the number of shares of the Company's
Common Stock issuable to the holder upon exercise of this Warrant and conversion
of the Shares issued thereupon.

                                       4

<PAGE>   36

            (a) DEFINITION OF NEW SECURITIES. Except as set forth below, "New
Securities" shall mean any shares of capital stock of the Company, including
Common Stock and Preferred Stock, whether now authorized or not, and rights,
options or warrants to purchase said shares of Common Stock or Preferred Stock,
and securities of any type whatsoever that are, or may become, convertible into
or exercisable for said shares of Common Stock or Preferred Stock.
Notwithstanding the foregoing, "New Securities" does not include: (i) Common
Stock issuable upon conversion of any Preferred Stock outstanding as of the
grant date; (ii) securities offered to the public generally pursuant to a
registration statement under the Securities Act; (iii) securities issued
pursuant to the acquisition of another corporation by the Company by merger,
purchase of substantially all of the assets or shares or other reorganization;
(iv) shares of the Company's Common Stock or related options convertible into or
exercisable for such Common Stock issued to employees, officers and directors
of, and consultants to, the Company, pursuant to any compensatory benefit plan;
(v) stock issued pursuant to any rights or agreements, including, without
limitation, convertible securities, options and warrants, provided that the
Company shall have complied with the right of first refusal established by this
SECTION 16 with respect to the initial sale or grant by the Company of such
rights or agreements; or (vi) stock issued in connection with any stock split,
reverse stock split, stock dividend, combination or recapitalization by the
Company.

            (b) NOTICE OF RIGHT. In the event the Company proposes to undertake
an issuance of New Securities, it shall give the holder written notice of its
intention, describing the type of New Securities and the price and terms upon
which the Company proposes to issue the same. The holder shall have fifteen (15)
days from the date of receipt of any such notice to agree to purchase shares of
such New Securities (up to the amount referred to in this SECTION 16), for the
price and upon the terms specified in the notice, by giving written notice to
the Company and stating therein the quantity of New Securities to be purchased.

            (c) EXERCISE OF RIGHT. If the holder exercises its right of first
refusal hereunder, the closing of the purchase of the New Securities with
respect to which such right has been exercised shall take place within ninety
(90) calendar days after the holder gives notice of such exercise, which period
of time shall be extended in order to comply with applicable laws and
regulations. Upon exercise of such right of first refusal, the Company and the
holder shall be legally obligated to consummate the purchase contemplated
thereby and shall use their best efforts to secure any approvals required in
connection therewith.

            (d) LAPSE AND REINSTATEMENT OF RIGHT. In the event the holder fails
to exercise the right of first refusal provided in this SECTION 16 within said
fifteen (15) day period, the Company shall have ninety (90) days thereafter to
sell or enter into an agreement (pursuant to which the sale of New Securities
covered thereby shall be closed, if at all, within sixty (60) days from the date
of said agreement) to sell the New Securities not elected to be purchased by the
holder at the price and upon the terms no more favorable to the purchasers of
such securities than specified in the Company's notice. In the event the Company
has not sold the New Securities or entered into an agreement to sell the New
Securities within said ninety (90) day period (or sold and issued New Securities
in accordance with the foregoing within sixty (60) days from the date of said
agreement), the Company shall not thereafter issue or sell any New Securities
without first offering such securities to the holder in the manner provided
above.

            (e) ASSIGNMENT. The right of the holder to purchase any part of the
New Securities may be assigned in whole or in part to any partner, subsidiary,
affiliate or shareholder of the holder.

            (f) TERMINATION OF RIGHT OF FIRST REFUSAL. The right of first
refusal granted under SECTION 16 shall terminate on and be of no further force
or effect upon the closing of a firmly underwritten public offering of the
securities of the Company.

        17. AMENDMENT. The terms of this Warrant may be amended, modified or
waived only with the written consent of the Holder and the Company.

        18. REPRESENTATIONS AND COVENANTS OF THE HOLDER. This Preferred Stock
Purchase Warrant has been entered into by the Company in reliance upon the
following representations and covenants of the Holder, which by its execution
hereof the Holder hereby confirms:

                                       5

<PAGE>   37

            (a) INVESTMENT PURPOSE. The right to acquire Preferred Stock
issuable upon exercise of the Holder's rights contained herein or Common Stock
issuable upon conversion thereof (the "Conversion Shares") will be acquired for
investment and not with a view to the sale or distribution of any part thereof,
and the Holder has no present intention of selling or engaging in any public
distribution of the same except pursuant to a registration or exemption. The
Holder further represents that such Holder does not have any contract,
undertaking, agreement or arrangement with any person to sell, transfer, or
grant participations to such person or to any third person, with respect to any
of the Preferred Stock or Conversion Shares.

            (b) ACCREDITED INVESTOR. Holder is an "accredited investor" within
the meaning of the Securities and Exchange Rule 501 of Regulation D, as
presently in effect.

            (c) PRIVATE ISSUE. The Holder understands (i) that the Preferred
Stock issuable upon exercise of the Holder's rights contained herein and the
Conversion Shares is not registered under the 1933 Act or qualified under
applicable state securities laws on the ground that the issuance contemplated by
this Warrant will be exempt from the registration and qualifications
requirements thereof, and (ii) that the Company's reliance on such exemption is
predicated on the representations set forth in this SECTION 18.

            (d) FINANCIAL RISK. The Holder is an investor in securities of
companies in the development stage and has such knowledge and experience in
financial and business matters as to be capable of evaluating the merits and
risks of its investment and has the ability to bear the economic risks of its
investment.

            (e) DISCLOSURE OF INFORMATION. The Holder believes it has received
all the information it considers necessary or appropriate for deciding whether
to purchase the Warrant and the Preferred Stock issuable upon exercise thereof.
Such Holder further represents that it has had the opportunity to ask questions
and receive answers from the Company regarding the terms and conditions of the
Preferred Stock and the business, properties, prospects and financial condition
of the Company.

        19. NOTICES, TRANSFERS, ETC.

            (a) Any notice or written communication required or permitted to be
given to the Holder may be given by certified mail or delivered to the Holder at
the address most recently provided by the Holder to the Company.

            (b) Subject to compliance with applicable federal and state
securities laws, this Warrant may be transferred by the Holder with respect to
any or all of the shares purchasable hereunder. Upon surrender of this Warrant
to the Company, together with the assignment notice annexed hereto duly
executed, for transfer of this Warrant as an entirety by the Holder, the Company
shall issue a new warrant of the same denomination to the assignee. Upon
surrender of this Warrant to the Company, together with the assignment hereof
properly endorsed, by the Holder for transfer with respect to a portion of the
shares of Preferred Stock purchasable hereunder, the Company shall issue a new
warrant to the assignee, in such denomination as shall be requested by the
Holder hereof, and shall issue to such Holder a new warrant covering the number
of shares in respect of which this Warrant shall not have been transferred.

            (c) In case this Warrant shall be mutilated, lost, stolen or
destroyed, the Company shall issue a new warrant of like tenor and denomination
and deliver the same (i) in exchange and substitution for and upon surrender and
cancellation of any mutilated Warrant, or (ii) in lieu of any Warrant lost,
stolen or destroyed, upon receipt of an affidavit of the Holder or other
evidence reasonably satisfactory to the Company of the loss, theft or
destruction of such Warrant

        20. NO IMPAIRMENT. The Company will not, by amendment of its Certificate
or through any reclassification, capital reorganization, consolidation, merger,
sale or conveyance of assets, dissolution, liquidation, issue or sale of
securities or any other voluntary action, avoid or seek to avoid the observance
of performance of any of the terms of this Warrant, but will at all times in
good faith assist in the carrying out of all such terms and in the taking of all
such action as may be necessary or appropriate in order to protect the rights of
the Holder.

                                       6.
<PAGE>   38

        21. GOVERNING LAW. The provisions and terms of this Warrant shall be
governed by and construed in accordance with the internal laws of the State of
California.

        22. SUCCESSORS AND ASSIGNS. This Warrant shall be binding upon the
Company's successors and assigns and shall inure to the benefit of the Holder's
successors, legal representatives and permitted assigns.

        23. BUSINESS DAYS. If the last or appointed day for the taking of any
action required or the expiration of any rights granted herein shall be a
Saturday or Sunday or a legal holiday in California, then such action may be
taken or right may be exercised on the next succeeding day which is not a
Saturday or Sunday or such a legal holiday.

        24. QUALIFYING PUBLIC OFFERING. If the Company shall effect a firm
commitment underwritten public offering of shares of Common Stock which results
in the conversion of the Preferred Stock into Common Stock pursuant to the
Certificate in effect immediately prior to such offering, then, effective upon
such conversion, this Warrant shall change from the right to purchase shares of
Preferred Stock to the right to purchase shares of Common Stock, and the Holder
shall thereupon have the right to purchase, at a total price equal to that
payable upon the exercise of this Warrant in full, the number of shares of
Common Stock which would have been receivable by the Holder upon the exercise of
this Warrant for shares of Preferred Stock immediately prior to such conversion
of such shares of Preferred Stock into shares of Common Stock, and in such event
appropriate provisions shall be made with respect to the rights and interest of
the Holder to the end that the provisions hereof (including, without limitation,
the provisions for the adjustment of the Purchase Price and of the number of
shares purchasable upon exercise of this Warrant and the provisions relating to
the net issue election) shall thereafter be applicable to any shares of Common
Stock deliverable upon the exercise hereof.

        25. VALUE. The Company and the Holder agree that the value of this
Warrant on the date of grant is $100.

Dated:  May ____, 1999                     CHEMCONNECT, INC.

                                           By: EXHIBIT ONLY
                                               --------------------------------

                                           Name: Phil J. Ringo
                                                 ------------------------------

                                           Title: President and COO
                                                  -----------------------------

               [CORPORATE SEAL]

Attest:

----------------------------

                                       7.
<PAGE>   39

                                  SUBSCRIPTION

To: ___________________________________________________     Date:______________

        The undersigned hereby subscribes for ____________ shares of Preferred
Stock covered by this Warrant. The certificate(s) for such shares shall be
issued in the name of the undersigned or as otherwise indicated below:

                                      Signature:
                                                -------------------------------

                                      Name for Registration:
                                                            -------------------

                                      Mailing Address:
                                                      -------------------------

                                      -----------------------------------------

                            NET ISSUE ELECTION NOTICE

To: ___________________________________________________     Date:______________

        The undersigned hereby elects under SECTION 4 to surrender the right to
purchase __________ shares of Preferred Stock pursuant to this Warrant. The
certificate(s) for such shares issuable upon such net issue election shall be
issued in the name of the undersigned or as otherwise indicated below:

                                      Signature:
                                                -------------------------------

                                      Name for Registration:
                                                            -------------------

                                      Mailing Address:
                                                      -------------------------

                                      -----------------------------------------

<PAGE>   40

                                   ASSIGNMENT

        For value received ______________________________ hereby sells, assigns
and transfers unto ____________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________

            [Please print or typewrite name and address of Assignee]
_______________________________________________________________________________
the within Warrant, and does hereby irrevocably constitute and appoint
____________________________________ its attorney to transfer the within Warrant
on the books of the within named Company with full power of substitution on the
premises.

Dated:__________________________

In the Presence of:

________________________________

<PAGE>   41

                                    EXHIBIT A

                      RESTATED CERTIFICATE OF INCORPORATION

                               See attached pages.

<PAGE>   42

                                    EXHIBIT B

                              CAPITALIZATION TABLE

                               See attached pages.

<PAGE>   43

                                    EXHIBIT I

                               ANCILLARY DOCUMENTS

Certificate of Secretary
UCC Financing Statement Attachment - Annex "A"
Insurance Request

<PAGE>   44

                                CHEMCONNECT, INC.

                            CERTIFICATE OF SECRETARY

        The undersigned, _______________, hereby certifies that:

        1.____________He/She is the duly elected and acting Secretary of
CHEMCONNECT, INC., a Delaware corporation (the "Company").

        2.____________That on the date hereof, each person listed below holds
the office in the Company indicated opposite his or her name and that the
signature appearing thereon is the genuine signature of each such person:

<TABLE>
<CAPTION>
        NAME                                OFFICE                                    SIGNATURE
        ----                                ------                                    ---------
<S>                                        <C>                                       <C>
        Phil J. Ringo                       President and COO                         _______________________
        _______________________             _______________________                   _______________________
        _______________________             _______________________                   _______________________
</TABLE>

        3.____________Attached hereto as EXHIBIT A is a true and correct copy of
the Certificate of Incorporation of the Company, as amended, as in effect as of
the date hereof.

        4.____________Attached hereto as EXHIBIT B is a true and correct copy of
the Bylaws of the Company, as amended, as in effect as of the date hereof.

        5.____________Attached hereto as EXHIBIT C is a copy of the resolutions
of the Board of Directors of the Company authorizing and approving the Company's
execution, delivery and performance of a lease line with Lighthouse Capital
Partners II, L.P.

        IN WITNESS WHEREOF, the undersigned has executed this Certificate of
Secretary this ____ day of May 1999.

                                          CHEMCONNECT, INC.

                                          By:
                                              ---------------------------------

                                          Name:
                                                -------------------------------

                                          Title:
                                                -------------------------------

        I, the President and COO of the Company, do hereby certify that
_________________ is the duly qualified, elected and acting Secretary/Assistant
Secretary of the Company and that the above signature is his or her genuine
signature.

        IN WITNESS WHEREOF, the undersigned has executed and delivered this
Certificate of Secretary this ____ day of May 1999. --------------
CHEMCONNECT, INC.

                                           By: EXHIBIT ONLY
                                              ---------------------------------

                                           Name: Phil J. Ringo
                                                 ------------------------------

                                           Title: President and COO
                                                  -----------------------------

<PAGE>   45
                                    ANNEX "A"

                     UCC-1 FINANCING STATEMENT CONTINUATION

DEBTOR/LESSEE/TRANSFEROR:                  CHEMCONNECT, INC.

SECURED PARTY/LESSOR/TRANSFEREE:           LIGHTHOUSE CAPITAL PARTNERS II, L.P.

________________________________________________________________________________

COLLATERAL DESCRIPTION:

        All now owned or hereafter acquired equipment, software and other
personal property leased by Lessor to Lessee pursuant to any present or future
equipment lease, together with all substitutions, replacements, additions,
accessions, proceeds, and products of to or for any of the foregoing.

        Lessee has no right to sell or otherwise dispose of any of the
foregoing.

        As provided in Uniform Commercial Code Section 9408, the execution and
filing of this financing statement is not intended to imply and in no way
constitutes evidence that the described items of property are owned by the
Debtor/Lessee/Transferor. However, if notwithstanding the intent of the parties,
the Lease is held to create a secured financing or lease for security, the
Lessee shall be deemed to have granted to Lessor a security interest in the
above described equipment and other property.

                            -------------------         -------------------
                            Lessee Initials             Lessor Initials

<PAGE>   46

                              EVIDENCE OF INSURANCE

1.      CHEMCONNECT, INC.

RE:     Master Equipment Lease Agreement No. 219 ("Lease")

As required by SECTION 8 of the referenced Lease, please provide evidence of
insurance as outlined below:

~       "all risk" insurance against loss or damage to the equipment naming
        LIGHTHOUSE CAPITAL PARTNERS II, L.P. as LOSS PAYEE with respect to the
        equipment.

Minimum amount of "all risk" coverage: $700,000

-       commercial general liability insurance in an amount of at least
        $2,000,000 naming LIGHTHOUSE CAPITAL PARTNERS II, L.P. as an ADDITIONAL
        INSURED.

General Information:

CERTIFICATE HOLDER:

               Lighthouse Capital Partners II, L.P.
               100 Drake's Landing Road, Suite 260
               Greenbrae, CA 94904-3121
               Attn.:  Contract Administration

If you or your agent have any questions we can be reached at the above address
or by,

               phone:     415-925-3370

               fax:       415-925-3387

               e-mail:    leasing@lighthse.com

Please note that the above Certificate(s) of Insurance are required PRIOR to
funding under the Lease.

<PAGE>   47

     LEASE LINE SCHEDULE NO. 01, dated May 5, 1999 ("Lease Line Schedule"),
                                       to
  MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999 ("Master Lease"),
                                 by and between
                LIGHTHOUSE CAPITAL PARTNERS II, L.P., a Delaware
                       limited partnership ("Lessor") and
             CHEMCONNECT, INC., a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

IN CONSIDERATION of the mutual covenants contained herein, the parties agree as
follows:

        LEASE LINE. The total Lessor's Cost of all units of Equipment under all
Equipment Schedules pursuant to this Lease Line Schedule shall not exceed
$700,000.00 (the "Commitment"). "LESSOR'S COST" means, with respect to a unit of
Equipment, the total cost to Lessor of purchasing such unit, as indicated on the
applicable Equipment Schedule. Lessor's obligation to fund Equipment Schedules
under the Commitment shall terminate on December 31, 1999 (the "Commitment
Termination Date"). The minimum Lessor's Cost for each Delivery & Acceptance
Certificate shall be $10,000.00.

        RENTAL FACTOR. The Rental Factor for each Equipment Schedule will be
2.98% of scheduled Lessor's Cost per month, payable monthly in advance. The
Rental Payment under a particular Equipment Schedule shall be an amount equal to
the product of (a) the Rental Factor and (b) the aggregate Lessor's Cost of
Equipment subject to such Equipment Schedule.

        INTERIM RENT. The daily Interim Rent factor shall be equal to 0.0208%
for each item of Equipment (the "Interim Rate"). The daily Interim Rent payment
shall be an amount equal to the product of (a) 0.0208%, and (b) the Lessor's
Cost for each item of Equipment.

        ADVANCE RENT. On the Commencement Date set forth in each Equipment
Schedule to this Lease Line Schedule, Lessee shall pay to Lessor advance rent
equal to the product of (a) the Rental Factor and (b) the aggregate Lessor's
Cost of Equipment subject to such Equipment Schedule ("Advance Rent"), to be
applied toward the last Rental Payment due from Lessee to Lessor under each
Equipment Schedule.

        EXPENSES. Lessee agrees to reimburse Lessor for up to One Thousand
Dollars ($1,000.00) of expenses incurred in connection with the negotiation and
documentation of this transaction, promptly upon receipt of an invoice.

        ELIGIBLE EQUIPMENT. All equipment to be financed under an Equipment
Schedule must be Eligible Equipment. "Eligible Equipment" means the following
types of equipment to the extent acceptable to Lessor:

        Various new and used computers, peripherals, analytical and test
equipment, laboratory equipment and furniture, office furniture and equipment,
software in an amount not to exceed Two Hundred Ten Thousand Dollars ($210,000),
and other equipment as mutually agreed to by Lessee and Lessor, together with
all replacements, parts, cables, repairs, additions and accessories incorporated
therein or affixed thereto and all operating manuals and manufacturer's
instructions (collectively hereinafter called the "Equipment"). Such
replacements, parts, cables, repairs, additions and accessories shall (whether
or not purchased by Lessor) be considered part of the Equipment for all purposes
and, when installed in or attached to the Equipment (unless otherwise agreed),
be or become the property of the Lessor. Except as otherwise specifically
provided or the context so requires, the term "Equipment" includes operating
system or other bundled software which is delivered on or with the Equipment and
which constitutes an accession that could not be removed upon Lease Termination
without adversely affecting the functionality of Equipment in which it is
installed or is included on the Equipment Schedules. Equipment that is older
than ninety (90) days will be valued at its net book value, provided however,
that with respect to the first Equipment Schedule under this Lease Line,
Equipment that is older than one hundred twenty (120) days will be valued at its
net book value.

        COMMENCEMENT DATE. The "Commencement Date" for each Equipment Schedule
shall be the first day of the calendar month following the Acceptance Date for
the items of Equipment subject to such Equipment Schedule.

                                       1.
<PAGE>   48

        LEASE TERMINATION OPTIONS. Upon Lease Termination (as defined in the
Master Lease), Lessee will have, with respect to all but not less than all of
the Equipment governed by this Lease Line Schedule, the option to (a) purchase
the Equipment for the lesser of its then fair market value or twenty percent
(20%) of Lessor's Cost, (b) renew the Lease or (c) return the Equipment to
Lessor as provided in SECTION 6 of the Master Lease.

        ADVANCE NOTICE PERIOD. The "Advance Notice Period" shall be at least
ninety (90) days, but not more than 180 days, prior to Lease Termination (as
defined in the Master Lease) of Equipment Schedule No. 01 to this Lease Line
Schedule.

        AUTOMATIC EXTENSION PERIOD. The "Automatic Extension Period" shall equal
three (3) months and affects each Equipment Schedule under this Lease Line
Schedule.

        INSURANCE. The amount of commercial general liability insurance (other
than products liability coverage and completed operations insurance) required
under the Master Lease shall be at least $2,000,000 per occurrence. The amount
of the products liability and completed operations insurance under the Master
Lease shall be at least $2,000,000 per occurrence.

        FINANCIAL STATEMENTS. Lessee shall deliver to Lessor: (a) as soon as
available, but in any event within twenty (20) days after the end of each month,
a company prepared balance sheet, income statement and cash flow statement
covering Lessee's operations during such period, certified by an officer of
Lessee reasonably acceptable to Lessor; (b) as soon as available, but in any
event within ninety (90) days after the end of Lessee's fiscal year, audited
financial statements of Lessee prepared in accordance with generally accepted
accounting principles, consistently applied, together with an unqualified
opinion (other than a going concern qualification) on such financial statements
of an independent certified public accounting firm reasonably acceptable to
Lessor; (c) promptly upon becoming available, copies of all statements, reports,
budgets, sales projections, operating plans and notices sent or made available
generally by Lessee to its security holders; (d) immediately upon receipt of
notice thereof, a report of any material legal actions pending or threatened
against Lessee; and (e) such other financial information as Lessor may
reasonably request from time to time.

        MAINTENANCE SERVICE CONTRACTS. Lessee shall obtain and keep in effect at
all times during the Lease Term (and any renewal or extension thereof),
maintenance service contracts covering any Equipment with (i) a Lessor's Cost in
excess of $10,000 and/or (ii) Equipment for which maintenance service contracts
are customarily available with the Equipment supplier or with suppliers of
maintenance services approved by Lessor, such approval not to be unreasonably
withheld.

        INSTALLATION, HANDLING AND DELIVERY CHARGES. Any handling and delivery
charge to cover all Equipment transportation, rigging, drayage, packing,
installation and handling to and from vendor's plant and upon return to Lessor's
designated location shall be paid by Lessee.

        MISCELLANEOUS TAXES. Without limitation of the provisions of the Master
Lease, Lessee agrees to pay and to indemnify Lessor for any sales or use tax and
any property tax in connection with the sale, lease or use of the Equipment.

        LATE FEE. Lessee shall pay a late charge on any rent payments or other
sums due hereunder which are more than ten (10) days past due, in an amount
equal to 2% of the past due amount, payable on demand.

        DEFAULT RATE. The Default Rate of interest on late payments shall be
eighteen percent (18%) per annum.

        NOTICES. All notices shall be addressed as follows:

        IF TO LESSOR:                            IF TO LESSEE:

        Lighthouse Capital Partners II, L.P.     ChemConnect, Inc.
        100 Drake's Landing, Suite 260           44 Montgomery Street, Suite 250
        Greenbrae, CA 94904-3121                 San Francisco, CA 94104
        Attn.:  Contract Administration          Attn.:  Chief Financial Officer
        Phone: (415) 925-3370                    Phone: (415) 364.3300
        Fax: (415) 925-3387                      Fax: (415) 646-0010

                                       2
<PAGE>   49

        CONDITIONS TO THE FIRST EQUIPMENT SCHEDULE. On or prior to the date of
execution of the first Equipment Schedule under this Lease Line Schedule, Lessor
shall have received in form and substance satisfactory to Lessor, each of the
following:

        1.      A Warrant substantially in the form of EXHIBIT H to the Master
                Lease.

        2.      Copies, certified by the Secretary or Assistant Secretary or
                Chief Financial Officer of Lessee, of: (i) the Articles of
                Incorporation and By-Laws of Lessee (as amended to the date of
                the Lease) and (ii) the resolutions adopted by Lessee's board of
                directors authorizing the execution and delivery of this Lease,
                the Lease Line Schedule, the Equipment Schedules, the Warrant
                and the other documents referred in this Lease Line Schedule and
                the performance by Lessee of its obligations in such documents.

        3.      A Good Standing Certificate (including franchise tax status)
                with respect to Lessee from Lessee's state of incorporation,
                dated a date reasonably close to the date of acceptance of the
                Lease by Lessor.

        4.      A Software Rider substantially in the form of ANNEX B to this
                Lease Line Schedule.

        5.      Evidence of the insurance coverage required by SECTION 8 of the
                Master Lease.

        6.      All necessary consents of shareholders and other third parties
                with respect to the subject matter of the Master Lease, the
                Lease Line Schedule, the Equipment Schedules and the Warrant.

        CONDITIONS TO ALL FUNDINGS UNDER ALL EQUIPMENT SCHEDULES. On or prior to
each funding under each Equipment Schedule under this Lease Line Schedule, each
of the following conditions shall have been satisfied:

        1.      No Event of Default or event which, with notice or lapse of time
                or both, would become an Event of Default, has occurred and is
                continuing.

        2.      Lessor shall have received a Software Licenses Assignment
                Agreement in substantially the form of ANNEX B-1 to this Lease
                Line Schedule with respect to each Vendor of software to be
                financed under this Lease Line Schedule.

        3.      Lessor shall have received all necessary or desirable estoppel
                certificates and UCC filings, releases or terminations.

        4.      Lessor shall have used its best efforts to obtain a landlord
                waiver and consent in substantially the form of EXHIBIT E to the
                Master Lease with respect to each equipment location.

        5.      There shall not have occurred (i) any material adverse change to
                the general affairs, management, results of operations,
                condition (financial or otherwise) or prospects of Lessee,
                whether or not arising from transactions in the ordinary course
                of business, or (ii) any material adverse deviation by Lessee
                from the business plan of Lessee presented to and not
                disapproved by Lessor, since the date of the Master Lease.

        6.      Lessee shall have delivered to Lessor an Equipment Schedule
                covering the appropriate funding period.

        7.      Lessee shall have delivered to Lessor (i) in the case of a
                sale-leaseback, original vendor invoices, copies of canceled
                checks or other proof of payment, a Bill of Sale, a Delivery and
                Acceptance Certificate, and any UCC filings or other notices
                deemed necessary or desirable in connection with the
                sale-leaseback or (ii) at Lessor's request, in the case of a
                purchase of new equipment in excess of $50,000 from an equipment
                vendor, a Purchase Order and Invoice Assignment and a Delivery
                and Acceptance Certificate.

        8.      Payment of the Advance Rent.

                                       3
<PAGE>   50

        9.      All terms and conditions in the Equipment Schedule shall have
                been satisfied by the Acceptance Date for the Equipment under
                such Equipment Schedule.

        All other documents as Lessor shall have reasonably requested.

LESSEE:                                    LESSOR:

CHEMCONNECT, INC.                          LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By:  /s/ Philip J. Ringo                   By: LIGHTHOUSE MANAGEMENT
   ---------------------------------           PARTNERS II, L.P.,
                                               its general partner
Name: Phil J. Ringo
      ------------------------------

Title: President and COO                   By: LIGHTHOUSE CAPITAL
       -----------------------------           PARTNERS, INC.,
                                               its general partner

                                               By: /s/ Thomas Conneely
                                                  -----------------------------

                                               Name: Thomas Conneely
                                                     --------------------------

                                               Title: Vice President, Operations
                                                      -------------------------

ANNEX A      -     Stipulated Loss Value Table
ANNEX B      -     Software Rider
ANNEX B-1    -     Software License Assignment Agreement

                                       4
<PAGE>   51

                                     ANNEX A

                           STIPULATED LOSS VALUE TABLE
                                       TO
                LEASE LINE SCHEDULE NO. 01, dated May 5, 1999, to
      MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999
     ("Master Lease"), by and between LIGHTHOUSE CAPITAL PARTNERS II, L.P.,
        a Delaware limited partnership ("Lessor"), and CHEMCONNECT, INC.,
                       a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

In the case of an Event of Loss, the Stipulated Loss Value for each item of
leased Equipment is the Lessor's Cost for the item multiplied by Stipulated Loss
Value Percentage for the Rent Payment Number following the month of the Event of
Loss.

<TABLE>
<CAPTION>
                                 Stipulated                                                  Stipulated
         Rent                        Loss                      Rent                             Loss
        Payment                     Value                    Payment                            Value
        Number                   Percentage                   Number                         Percentage
        ------                   ----------                   ------                         ----------
<S>                               <C>                         <C>                              <C>
          1                        111.88%                      19                              69.19%
          2                        109.78%                      20                              66.76%
          3                        106.95%                      21                              64.31%
          4                        104.54%                      22                              61.85%
          5                        102.11%                      23                              59.36%
          6                         98.78%                      24                              56.86%
          7                         96.64%                      25                              54.33%
          8                         94.47%                      26                              51.79%
          9                         92.28%                      27                              49.22%
         10                         90.07%                      28                              46.63%
         11                         87.84%                      29                              44.03%
         12                         85.59%                      30                              41.40%
         13                         83.31%                      31                              38.74%
         14                         81.09%                      32                              35.07%
         15                         78.69%                      33                              31.64%
         16                         76.35%                      34                              27.76%
         17                         73.99%                      35                              23.88%
         18                         71.60%                      36 and thereafter               20.00%
</TABLE>

Lessee:   PJR                                     Lessor:     R
        ---------------                                    ---------------

<PAGE>   52

                                     ANNEX B

                                 SOFTWARE RIDER

        THIS SOFTWARE RIDER (this "Rider") is made a part of Lease Line Schedule
No. 01 (the ("Lease Line Schedule") dated May 5, 1999, by and between LIGHTHOUSE
CAPITAL PARTNERS II, L.P., a Delaware limited partnership ("Lessor") and
CHEMCONNECT, INC., a Delaware corporation ("Lessee").

All capitalized terms used and not otherwise defined herein are defined in the
Lease Line Schedule.

        In the event any computer software (as described in any applicable
Equipment Schedule and collectively with all manuals, updates, revisions,
program and data files, and documentation relating thereto or used or usable in
connection therewith, the "Software"), is purchased or licensed pursuant to the
Lease Line Schedule, then, in addition to all other terms and conditions of the
Master Lease and the Lease Line Schedule, all of which are incorporated herein
by this reference:

        1. SOFTWARE AS GENERAL INTANGIBLES. All Software shall be "Equipment" as
defined under the Lease Line Schedule. Lessee hereby grants to Lessor as
collateral security for Lessee's payment and performance of all Lessee's
obligations of payment and performance under this Rider, the Lease Line
Schedule, the Master Lease, and every other present or future Equipment Schedule
or other agreement between Lessee and Lessor, a security interest in all of its
right, title and interest in and to the Software, including without limitation
general intangibles, licenses, and intellectual property rights with respect
thereto, but excluding all licenses and other agreements that by law or by the
terms thereof may not be assigned by Lessee or may only be assigned by Lessee
with the consent of the other party to such license or other agreement, and all
substitutions, modifications, replacements, additions, accessions, proceeds, and
products of, to, or for any of the foregoing.

        2. EXCLUSION OF WARRANTIES. Without limiting the generality of all
exclusions of warranty set forth in the Lease Line Schedule and Master Lease,
Lessor makes no and specifically excludes any representation or warranty
relating to any Software, including without limitation any warranty of title,
validity or enforceability of license, noninfringement, availability or quality
of vendor support, or fitness for any particular purpose.

        3. LICENSE ASSIGNMENT AGREEMENT. Lessee will use its best efforts to
obtain a License Assignment Agreement in form and substance satisfactory to
Lessor and as set forth on EXHIBIT 1 hereto (the "Software License Assignment
Agreement")prior to the advance by Lessor of any funds to any party with respect
to the Software. Breach by Lessee of any term or condition of any license
agreement governing the right to use any Software shall be an Event of Default
under SECTION 16(ii) of the Master Lease if such breach is likely to have a
material adverse effect on the Equipment or Lessor's rights under the Lease Line
Schedule, Master Lease or any other documents relating to the lease of the
Equipment to Lessee.

        4. APPLICABILITY OF LEASE. The Master Lease, Lease Line Schedule,
Equipment Schedule, Software License Assignment Agreement, and this Rider, and
all documents entered into in connection therewith, govern Lessee's obligations
of payment and performance to Lessor with respect to the Software, whether or
not the Software represents goods capable of being leased pursuant to the UCC.

        5. LICENSE PERFORMANCE. Lessee agrees that in addition to Lessor's
remedies following an Event of Default, Lessor may upon notice to Lessee
requiring the same cause Lessee to cease all use of the Software and to assemble
and deliver to Lessor the same in electronic or other form. Lessee shall remit
to Lessor upon demand any amounts due and payable with respect to the licensing
of any Software or the assignment thereof. Lessee agrees that monetary damages
are not a sufficient remedy and will not adequately compensate Lessor for
Lessee's breach of this Section, and that Lessor shall be entitled to seek
specific performance or other injunctive or equitable relief.

<PAGE>   53

        6. INTEGRATION. This Rider represents the entirety of the understanding
between the parties with respect to its subject matter, and may only be modified
by a written instrument signed by the party to be charged. All rights and
remedies of Lessor herein are in addition to, and not in limitation of, the
rights and remedies of Lessor under the Lease.

LESSEE:                                    LESSOR:

CHEMCONNECT, INC.                          LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By: EXHIBIT ONLY                           By: LIGHTHOUSE MANAGEMENT
    ---------------------------------          PARTNERS II, L.L.C.,
Name: Phil J. Ringo                            its general partner
      ------------------------------

Title: President and COO                   By: LIGHTHOUSE CAPITAL PARTNERS,
       -----------------------------           INC., its general partner

                                               By:
                                                  -----------------------------
                                               Name: Thomas Conneely
                                                     --------------------------
                                               Title: Vice President, Operations
                                                      -------------------------

<PAGE>   54

                                    ANNEX B-1
                                    EXHIBIT 1
                      SOFTWARE LICENSE ASSIGNMENT AGREEMENT

        This SOFTWARE LICENSE ASSIGNMENT AGREEMENT (this "Agreement") is entered
into May 5, 1999, by and between ______________________ ("Vendor"), LIGHTHOUSE
CAPITAL PARTNERS II, L.P., a Delaware limited partnership ("Lessor") and
CHEMCONNECT, INC., a Delaware corporation ("Lessee"), with respect to certain
items of computer software purchased or licensed from Vendor as more
specifically described in attachments hereto (the "Software") in connection with
that certain Equipment Schedule No. 01 between Lessee and Lessor (collectively
with all documents entered into in connection therewith, the "Lease") dated May
5, 1999.

        1. ACKNOWLEDGMENT OF LICENSE. The parties acknowledge that the right to
use the Software is being acquired pursuant to a software license agreement (the
"License") between Vendor and Lessee, and agree as follows:

           (a) Lessee reaffirms all of its rights and obligations under the
License and under the Lease. Lessor is not a party to the License, but is an
express third party beneficiary thereof.

           (b) Lessee assigns to Lessor all of its rights and benefits, but
Lessee retains all the obligations and burdens, under the License. Vendor
consents to such assignment.

           (c) Lessor sublicenses back to Lessee, expiring once there has been
an Event of Default under the Lease, the rights and benefits under the License.

        2. ASSIGNMENT. Lessor may upon notice to Vendor succeed to all of
Lessee's right, title and interest in and to the License, and may sell or assign
the same to any person, without the imposition of any transfer fee payable to
Vendor, effective upon such person's execution of the License, who shall upon
such execution succeed to the obligations and burdens under such license.

        3. NO COMMITMENT. This is not a commitment by Lessor to purchase or
finance any other items of software or hardware other than the Software.

        4. INTEGRATION. This Agreement represents the entirety of the
understanding between the parties with respect to its subject matter, and may
only be modified by a written instrument signed by the party to be charged.

VENDOR                                     LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By:                                        By: LIGHTHOUSE MANAGEMENT
   ---------------------------------           PARTNERS II, L.L.C.,
                                               its general partner

By:
   ---------------------------------           By: LIGHTHOUSE CAPITAL PARTNERS,
                                                   INC., its general partner
Title:
      ------------------------------           By:
                                                  -----------------------------

                                               Name: Thomas Conneely
                                                     --------------------------
CHEMCONNECT, INC.
                                               Title: Vice President, Operations
                                                      --------------------------
By: EXHIBIT ONLY
    --------------------------------

Name: Phil J. Ringo
      ------------------------------

Title: President and COO
       -----------------------------

<PAGE>   55
                                 SOFTWARE RIDER

        THIS SOFTWARE RIDER (this "Rider") is made a part of Lease Line Schedule
No. 01 (the ("Lease Line Schedule") dated May 5, 1999, by and between LIGHTHOUSE
CAPITAL PARTNERS II, L.P., a Delaware limited partnership ("Lessor") and
CHEMCONNECT, INC., a Delaware corporation ("Lessee").

All capitalized terms used and not otherwise defined herein are defined in the
Lease Line Schedule.

        In the event any computer software (as described in any applicable
Equipment Schedule and collectively with all manuals, updates, revisions,
program and data files, and documentation relating thereto or used or usable in
connection therewith, the "Software"), is purchased or licensed pursuant to the
Lease Line Schedule, then, in addition to all other terms and conditions of the
Master Lease and the Lease Line Schedule, all of which are incorporated herein
by this reference:

        1. SOFTWARE AS GENERAL INTANGIBLES. All Software shall be "Equipment" as
defined under the Lease Line Schedule. Lessee hereby grants to Lessor as
collateral security for Lessee's payment and performance of all Lessee's
obligations of payment and performance under this Rider, the Lease Line
Schedule, the Master Lease, and every other present or future Equipment Schedule
or other agreement between Lessee and Lessor, a security interest in all of its
right, title and interest in and to the Software, including without limitation
general intangibles, licenses, and intellectual property rights with respect
thereto, but excluding all licenses and other agreements that by law or by the
terms thereof may not be assigned by Lessee or may only be assigned by Lessee
with the consent of the other party to such license or other agreement, and all
substitutions, modifications, replacements, additions, accessions, proceeds, and
products of, to, or for any of the foregoing.

        2. EXCLUSION OF WARRANTIES. Without limiting the generality of all
exclusions of warranty set forth in the Lease Line Schedule and Master Lease,
Lessor makes no and specifically excludes any representation or warranty
relating to any Software, including without limitation any warranty of title,
validity or enforceability of license, noninfringement, availability or quality
of vendor support, or fitness for any particular purpose.

        3. LICENSE ASSIGNMENT AGREEMENT. Lessee will use its best efforts to
obtain a License Assignment Agreement in form and substance satisfactory to
Lessor and as set forth on EXHIBIT 1 hereto (the "Software License Assignment
Agreement")prior to the advance by Lessor of any funds to any party with respect
to the Software. Breach by Lessee of any term or condition of any license
agreement governing the right to use any Software shall be an Event of Default
under SECTION 16(ii) of the Master Lease if such breach is likely to have a
material adverse effect on the Equipment or Lessor's rights under the Lease Line
Schedule, Master Lease or any other documents relating to the lease of the
Equipment to Lessee.

        4. APPLICABILITY OF LEASE. The Master Lease, Lease Line Schedule,
Equipment Schedule, Software License Assignment Agreement, and this Rider, and
all documents entered into in connection therewith, govern Lessee's obligations
of payment and performance to Lessor with respect to the Software, whether or
not the Software represents goods capable of being leased pursuant to the UCC.

        5. LICENSE PERFORMANCE. Lessee agrees that in addition to Lessor's
remedies following an Event of Default, Lessor may upon notice to Lessee
requiring the same cause Lessee to cease all use of the Software and to assemble
and deliver to Lessor the same in electronic or other form. Lessee shall remit
to Lessor upon demand any amounts due and payable with respect to the licensing
of any Software or the assignment thereof. Lessee agrees that monetary damages
are not a sufficient remedy and will not adequately compensate Lessor for
Lessee's breach of this Section, and that Lessor shall be entitled to seek
specific performance or other injunctive or equitable relief.

<PAGE>   56

        6. INTEGRATION. This Rider represents the entirety of the understanding
between the parties with respect to its subject matter, and may only be modified
by a written instrument signed by the party to be charged. All rights and
remedies of Lessor herein are in addition to, and not in limitation of, the
rights and remedies of Lessor under the Lease.

LESSEE:                                    LESSOR:

CHEMCONNECT, INC.                          LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By: /S/ PHILIP J. RINGO                    By: LIGHTHOUSE MANAGEMENT
   ---------------------------------           PARTNERS II, L.L.C.,
                                               its general partner

Name: Phil J. Ringo                            By: LIGHTHOUSE MANAGEMENT
      ------------------------------           PARTNERS II, L.P.
                                                   its general partner

Title: President and COO
       -----------------------------

                                               By: /s/ THOMAS CONNEELY
                                                  -----------------------------

                                               Name: Thomas Conneely
                                                     --------------------------

                                               Title: Vice President, Operations
                                                      -------------------------

<PAGE>   57

                                    ANNEX B-1
                                    EXHIBIT 1
                      SOFTWARE LICENSE ASSIGNMENT AGREEMENT

        This SOFTWARE LICENSE ASSIGNMENT AGREEMENT (this "Agreement") is entered
into May 5, 1999, by and between ______________________ ("Vendor"), LIGHTHOUSE
CAPITAL PARTNERS III, L.P., a Delaware limited partnership ("Lessor") and
CHEMCONNECT, INC., a Delaware corporation ("Lessee"), with respect to certain
items of computer software purchased or licensed from Vendor as more
specifically described in attachments hereto (the "Software") in connection with
that certain Equipment Schedule No. 01 between Lessee and Lessor (collectively
with all documents entered into in connection therewith, the "Lease") dated May
5, 1999.

        1. ACKNOWLEDGMENT OF LICENSE. The parties acknowledge that the right to
use the Software is being acquired pursuant to a software license agreement (the
"License") between Vendor and Lessee, and agree as follows:

           (a) Lessee reaffirms all of its rights and obligations under the
License and under the Lease. Lessor is not a party to the License, but is an
express third party beneficiary thereof.

           (b) Lessee assigns to Lessor all of its rights and benefits, but
Lessee retains all the obligations and burdens, under the License. Vendor
consents to such assignment.

           (c) Lessor sublicenses back to Lessee, expiring once there has been
an Event of Default under the Lease, the rights and benefits under the License.

        2. ASSIGNMENT. Lessor may upon notice to Vendor succeed to all of
Lessee's right, title and interest in and to the License, and may sell or assign
the same to any person, without the imposition of any transfer fee payable to
Vendor, effective upon such person's execution of the License, who shall upon
such execution succeed to the obligations and burdens under such license.

        3. NO COMMITMENT. This is not a commitment by Lessor to purchase or
finance any other items of software or hardware other than the Software.

        4. INTEGRATION. This Agreement represents the entirety of the
understanding between the parties with respect to its subject matter, and may
only be modified by a written instrument signed by the party to be charged.

VENDOR                                     LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By:                                        By: LIGHTHOUSE MANAGEMENT
   ---------------------------------           PARTNERS II, L.L.C.,
                                               its general partner

By:
   ---------------------------------           By: LIGHTHOUSE MANAGEMENT
                                                   PARTNERS II, L.P.,
                                                   its general partner
Title:
      ------------------------------           By:
                                                  -----------------------------

                                               Name: Thomas Conneely
                                                     --------------------------

CHEMCONNECT, INC.
                                               Title: Vice President, Operations
                                                      -------------------------

By: EXHIBIT ONLY
    --------------------------------

Name: Phil J. Ringo
      ------------------------------

Title: President and COO
       -----------------------------

<PAGE>   58

     EQUIPMENT SCHEDULE NO. 01, dated May 5, 1999 ("Equipment Schedule") to
    LEASE LINE SCHEDULE NO. 01, dated May 5, 1999 ("Lease Line Schedule"), to
  MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999 ("Master Lease"),
       by and between LIGHTHOUSE CAPITAL PARTNERS II, L.P. ("Lessor") and
             CHEMCONNECT, INC., a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

Total Lessor's Cost:     The total Lessor's Cost under this Equipment Schedule
                         shall be an amount equal to the sum of the Lessor's
                         Cost under each Delivery and Acceptance Certificate
                         executed by Lessee between the date of this Equipment
                         Schedule and ten days prior to the Commencement Date,
                         and which refers to this Equipment Schedule.

Lease Term:              36 Months

Commencement Date:       June 1, 1999

Interim Rent:            On or about the Commencement Date, Lessor shall send
                         Lessee a "Summary of Equipment Schedule" in the form of
                         ANNEX A hereto, specifying, among other things, the
                         applicable Interim Rent; provided, however, that any
                         failure by Lessor to send Lessee a Summary of Equipment
                         Schedule shall not relieve Lessee of its obligation to
                         pay rent hereunder.

Rental Factor:           The Rental Factor shall be set forth in the Summary of
                         Equipment Schedule.

Rental Payments:         The amount of the monthly Rental Payments, calculated
                         in accordance with the Lease Line Schedule and payable
                         monthly in advance, shall be set forth in the Summary
                         of Equipment Schedule. Payments shall be made to
                         Lessor's address set forth in the Lease Line Schedule.

Rental Payment Dates:    First day of each calendar month.

Equipment Description:   The Equipment shall be described in each Delivery and
                         Acceptance Certificate executed by Lessee between the
                         date of this Equipment Schedule and the Commencement
                         Date, and which refers to this Equipment Schedule.
                         Delivery and Acceptance Certificates under this
                         Equipment Schedule must be received by Lessor no later
                         than ten business days prior to the Commencement Date.

Equipment Location:      44 Montgomery Street, Suite 250, San Francisco,
                         California 94104

Terms and Conditions:    The terms and conditions of the above-referenced Master
                         Lease and Lease Line Schedule are incorporated herein.
                         In addition, the following attachments apply to this
                         Equipment Schedule only: None.

<PAGE>   59

No Default:              No Event of Default or event which, with notice or
                         lapse of time or both, would become an Event of
                         Default, has occurred and is continuing.

LESSEE:                                    LESSOR:

CHEMCONNECT, INC.                          LIGHTHOUSE CAPITAL PARTNERS II, L.P.

By: /s/ PHILIP J. RINGO                    By: LIGHTHOUSE MANAGEMENT
   ---------------------------------           PARTNERS II, L.P.,
                                               its general partner

Name: Phil J. Ringo
                                           By: LIGHTHOUSE CAPITAL
Title: President and COO                       its general partner
       -----------------------------

                                               By: /s/ THOMAS CONNEELY
                                                  -----------------------------

                                               Name: Thomas Conneely
                                                     --------------------------

                                               Title: Vice President, Operations
                                                      -------------------------

<PAGE>   60

                                     ANNEX A

                     SUMMARY OF EQUIPMENT SCHEDULE NO. 01 to
                LEASE LINE SCHEDULE NO. 01, dated May 5, 1999, to
 MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999 ("Master Lease")
       by and between LIGHTHOUSE CAPITAL PARTNERS II, L.P. ("Lessor") and
              CHEMCONNECT, INC., a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

Total Lessor's Cost:                       $__________

Total Interim Rent:                        $__________

Rental Factor:                             2.98%

Rental Payments:                           36 payments of $
                                           each, payable monthly in advance

Amount of Advance Rent applied to this Equipment Schedule:   $__________

                                           LIGHTHOUSE CAPITAL PARTNERS II, L.P.

                                           By: LIGHTHOUSE MANAGEMENT
                                               PARTNERS II, L.P.,
                                               its general partner

                                           By: LIGHTHOUSE CAPITAL
                                               PARTNERS, INC.,
                                               its general partner

                                               By: EXHIBIT ONLY
                                                   ----------------------------

                                               Name: Thomas Conneely
                                                     --------------------------

                                               Title: Vice President, Operations
                                                      -------------------------

<PAGE>   61

                     SUMMARY OF EQUIPMENT SCHEDULE NO. 01 to
                LEASE LINE SCHEDULE NO. 01, dated May 5, 1999, to
  MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999 ("Master Lease")
       by and between LIGHTHOUSE CAPITAL PARTNERS II, L.P. ("Lessor") and
              CHEMCONNECT, INC., a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

Total Lessor's Cost:                       $629,913.14

Total Interim Rent:                        $0.00

Rental Factor:                             2.98%

Rental Payments:                           36 payments of $18,771.41
                                           each, payable monthly in advance

Amount of Advance Rent applied to this Equipment Schedule: $18,771.41

                                           LIGHTHOUSE CAPITAL PARTNERS II, L.P.

                                           By: LIGHTHOUSE MANAGEMENT
                                               PARTNERS II, L.P.,
                                               its general partner

                                               By: LIGHTHOUSE CAPITAL
                                                   PARTNERS, INC.,
                                                   its general partner

                                               By: /s/ THOMAS CONNEELY
                                                  -----------------------------
                                               Name: Thomas Conneely
                                                     --------------------------
                                               Title: Vice President, Operations
                                                      -------------------------

<PAGE>   62

                     SUMMARY OF EQUIPMENT SCHEDULE NO. 01 to
                LEASE LINE SCHEDULE NO. 01, dated May 5, 1999, to
  MASTER EQUIPMENT LEASE AGREEMENT NO. 219, dated May 5, 1999 ("Master Lease")
       by and between LIGHTHOUSE CAPITAL PARTNERS II, L.P. ("Lessor") and
              CHEMCONNECT, INC., a Delaware corporation ("Lessee").

(All capitalized terms not otherwise defined herein shall have the meanings
given to such terms in the Master Lease.)

Total Lessor's Cost                        $629,913.14

Total Interim Rent:                        $0.00

Rental Factor:                             2.98%

Rental Payments:                           36 payments of $18,771.41
                                           each, payable monthly in advance

Amount of Advance Rent applied to this Equipment Schedule:  $18,771.41

                                           LIGHTHOUSE CAPITAL PARTNERS II, L.P.

                                           By: LIGHTHOUSE MANAGEMENT
                                               PARTNERS II, L.P.,
                                               its general partner

                                               By: LIGHTHOUSE CAPITAL
                                                   PARTNERS, INC.,
                                                   its general partner

                                               By: /s/ THOMAS CONNEELY
                                                  -----------------------------

                                               Name: Thomas Conneely
                                                     --------------------------

                                               Title: Vice President, Operations
                                                      -------------------------

<PAGE>   63

THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE "1933 ACT"), OR ANY APPLICABLE STATE SECURITIES LAWS, AND MAY NOT
BE SOLD OR TRANSFERRED UNLESS SUCH SALE OR TRANSFER IS IN ACCORDANCE WITH THE
REGISTRATION REQUIREMENTS OF SUCH ACT AND APPLICABLE LAWS OR SOME OTHER
EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF SUCH ACT AND APPLICABLE LAWS IS
AVAILABLE WITH RESPECT THERETO.

                        PREFERRED STOCK PURCHASE WARRANT

Warrant No. __________                                 Number of Shares: 21,539
                                                       Series B Preferred Stock

                                CHEMCONNECT, INC.

                            Void after April 30, 2006

        1. ISSUANCE. This Warrant is issued to LIGHTHOUSE CAPITAL PARTNERS II,
L.P. by CHEMCONNECT, INC., a Delaware corporation (hereinafter with its
successors called the "Company").

        2. PURCHASE PRICE; NUMBER OF SHARES. The registered holder of this
Warrant (the "HOLDER"), commencing on the date hereof, is entitled upon
surrender of this Warrant with the subscription form annexed hereto duly
executed, at the principal office of the Company, to purchase from the Company
the following securities (collectively, the "SHARES") at a price per share of
$1.30 (the "PURCHASE PRICE"), 21,539 fully paid and nonassessable shares of
Series B Preferred Stock, $0.0001 par value, of the Company (the "PREFERRED
STOCK"). Until such time as this Warrant is exercised in full or expires, the
Purchase Price and the securities issuable upon exercise of this Warrant are
subject to adjustment as hereinafter provided. The person or persons in whose
name or names any certificate representing shares of Preferred Stock is issued
hereunder shall be deemed to have become the holder of record of the shares
represented thereby as at the close of business on the date this Warrant is
exercised with respect to such shares, whether or not the transfer books of the
Company shall be closed.

        3. PAYMENT OF PURCHASE PRICE. The Purchase Price may be paid (i) in cash
or by check, (ii) by the surrender by the Holder to the Company of any
promissory notes or other obligations issued by the Company, with all such notes
and obligations so surrendered being credited against the Purchase Price in an
amount equal to the principal amount thereof plus accrued interest to the date
of surrender, or (iii) by any combination of the foregoing.

        4. NET ISSUE ELECTION. The Holder may elect to receive, without the
payment by the Holder of any additional consideration, shares of Preferred Stock
equal to the value of this Warrant or any portion hereof by the surrender of
this Warrant or such portion to the Company, with the net issue election notice
annexed hereto duly executed, at the principal office of the Company. Thereupon,
the Company shall issue to the Holder such number of fully paid and
nonassessable shares of Preferred Stock as is computed using the following
formula:

                                    X=Y (A-B)
                                        ----
                                          A

where:      X = the number of shares of Preferred Stock to be issued to the
                Holder pursuant to this SECTION 4.

            Y = the number of shares of Preferred Stock covered by this Warrant
                in respect of which the net issue election is made pursuant to
                this SECTION 4.

            A = the Fair Market Value (defined below) of one share of Preferred
                Stock, as determined at the time the net issue election is made
                pursuant to this SECTION 4.

<PAGE>   64

            B = the Purchase Price in effect under this Warrant at the time
                the net issue election is made pursuant to this SECTION 4.

"FAIR MARKET VALUE" of a share of Preferred Stock (or Common Stock if the
Preferred Stock has been automatically converted into Common Stock) as of a
particular date (the "DETERMINATION DATE") shall mean:

                (a) If the net issue election is made in connection with and
        contingent upon the closing of the sale of the Company's Common Stock to
        the public in a public offering pursuant to a Registration Statement
        under the Securities Act of 1933 ("1933 ACT") (a "PUBLIC OFFERING"), and
        if the Company's Registration Statement relating to such Public Offering
        ("REGISTRATION STATEMENT") has been declared effective by the Securities
        and Exchange Commission, then the initial "Price to Public" specified in
        the final prospectus with respect to such offering multiplied by the
        number of shares of Common Stock into which each share of Preferred
        Stock is then convertible.

                (b) If the net issue election is not made in connection with and
        contingent upon a Public Offering, then as follows:

                        (i) If traded on a securities exchange or the Nasdaq
                National Market, the fair market value of the Common Stock shall
                be deemed to be the average of the closing or last reported sale
                prices of the Common Stock on such exchange or market over the
                five day period ending five business days prior to the
                Determination Date, and the fair market value of the Preferred
                Stock shall be deemed to be such fair market value of the Common
                Stock multiplied by the number of shares of Common Stock into
                which each share of Preferred Stock is then convertible;

                        (ii) If otherwise traded in an over-the-counter market,
                the fair market value of the Common Stock shall be deemed to be
                the average of the closing ask prices of the Common Stock over
                the five day period ending five business days prior to the
                Determination Date, and the fair market value of the Preferred
                Stock shall be deemed to be such fair market value of the Common
                Stock multiplied by the number of shares of Common Stock into
                which each share of Preferred Stock is then convertible; and

                        (iii) If there is no public market for the Common Stock,
                then fair market value shall be determined in good faith by the
                Company's Board of Directors.

        5. PARTIAL EXERCISE. This Warrant may be exercised in part, and the
Holder shall be entitled to receive a new warrant, which shall be dated as of
the date of this Warrant, covering the number of shares in respect of which this
Warrant shall not have been exercised.

        6. FRACTIONAL SHARES. In no event shall any fractional share of
Preferred Stock be issued upon any exercise of this Warrant. If, upon exercise
of this Warrant in its entirety, the Holder would, except as provided in this
SECTION 6, be entitled to receive a fractional share of Preferred Stock, then
the Company shall pay in lieu thereof, the Fair Market Value of such fractional
share in cash.

        7. EXPIRATION DATE; AUTOMATIC EXERCISE. This Warrant shall expire at the
close of business on April 30, 2006, and shall be void thereafter.
Notwithstanding the foregoing, this Warrant shall automatically be deemed to be
exercised in full pursuant to the provisions of SECTION 4 hereof, without any
further action on behalf of the Holder, immediately prior to the time this
Warrant would otherwise expire pursuant to the preceding sentence.

        8. RESERVED SHARES; VALID ISSUANCE. The Company covenants that it will
at all times from and after the date hereof reserve and keep available such
number of its authorized shares of Preferred Stock and Common Stock, $0.0001 par
value, of the Company (the "COMMON STOCK"), free from all preemptive or similar
rights therein, as will be sufficient to permit, respectively, the exercise of
this Warrant in full and the conversion into shares of Common Stock of all
shares of Preferred Stock receivable upon such exercise. The Company further
covenants that such shares as may be issued pursuant to such exercise and/or
conversion will, upon issuance, be duly

                                       2.

<PAGE>   65

and validly issued, fully paid and nonassessable and free from all taxes, liens
and charges with respect to the issuance thereof.

        9. STOCK SPLITS AND DIVIDENDS. If after the date hereof the Company
shall subdivide the Preferred Stock, by split-up or otherwise, or combine the
Preferred Stock, or issue additional shares of Preferred Stock in payment of a
stock dividend on the Preferred Stock, the number of shares of Preferred Stock
issuable on the exercise of this Warrant shall forthwith be proportionately
increased in the case of a subdivision or stock dividend, or proportionately
decreased in the case of a combination, and the Purchase Price shall forthwith
be proportionately decreased in the case of a subdivision or stock dividend, or
proportionately increased in the case of a combination.

        10. NO STOCKHOLDER RIGHTS. Except as expressly provided in this Warrant,
prior to exercise of this Warrant, the Holder shall not be entitled to any
rights of a stockholder with respect to the Shares, including without limitation
the right to vote such Shares, receive dividends or other distributions thereon,
exercise preemptive rights or be notified of stockholder meetings, and such
Holder shall not be entitled to any notice or other communication concerning the
business or affairs of the Company, provided, however, that nothing in this
SECTION 10 shall limit the right of the Holder to be provided the notices
required under the Warrant.

        11. MERGERS AND RECLASSIFICATIONS. If after the date hereof the Company
shall enter into any Reorganization (as hereinafter defined), then, as a
condition of such Reorganization, lawful provisions shall be made, and duly
executed documents evidencing the same from the Company or its successor shall
be delivered to the Holder, so that the Holder shall thereafter have the right
to purchase, at a total price not to exceed that payable upon the exercise of
this Warrant in full, the kind and amount of shares of stock and other
securities and property receivable upon such Reorganization by a holder of the
number of shares of Preferred Stock which might have been purchased by the
Holder immediately prior to such Reorganization, and in any such case
appropriate provisions shall be made with respect to the rights and interest of
the Holder to the end that the provisions hereof (including without limitation,
provisions for the adjustment of the Purchase Price and the number of shares
issuable hereunder and the provisions relating to the net issue election) shall
thereafter be applicable in relation to any shares of stock or other securities
and property thereafter deliverable upon exercise hereof. For the purposes of
this SECTION 11, the term "REORGANIZATION" shall mean and refer to (i) an
acquisition of the Company by another entity by means of a merger,
consolidation, or other transaction or series of related transactions resulting
in the exchange of the outstanding shares of the Company's capital stock such
that stockholders of the Company prior to such transaction own, directly or
indirectly, less than 50% of the voting power of the surviving entity, or (ii) a
sale or transfer of all or substantially all of the Company's asset to any other
person.

        12. CERTIFICATE OF ADJUSTMENT. Whenever the Purchase Price is adjusted,
as herein provided, the Company shall promptly deliver to the Holder a
certificate of the Company's chief financial officer setting forth the Purchase
Price after such adjustment and setting forth a brief statement of the facts
requiring such adjustment.

        13. NOTICES OF RECORD DATE, ETC. In the event of:

           (a) any taking by the Company of a record of the holders of any class
of securities for the purpose of determining the holders thereof who are
entitled to receive any dividend or other distribution, or any right to
subscribe for, purchase, sell or otherwise acquire or dispose of any shares of
stock of any class or any other securities or property, or to receive any other
right;

           (b) any reclassification of the capital stock of the Company, capital
reorganization of the Company, consolidation or merger involving the Company, or
sale or conveyance of all or substantially all of its assets; or

           (c) any voluntary or involuntary dissolution, liquidation or
winding-up of the Company;

then in each such event the Company will provide or cause to be provided to the
Holder a written notice thereof. Such notice shall be provided at least twenty
(20) business days prior to the date specified in such notice on which any such
action is to be taken.

                                       3.
<PAGE>   66

        14. REPRESENTATIONS, WARRANTIES AND COVENANTS. This Warrant is issued
and delivered by the Company and accepted by each Holder on the basis of the
following representations, warranties and covenants made by the Company:

            (a) The Company has all necessary authority to issue, execute and
deliver this Warrant and to perform its obligations hereunder. This Warrant has
been duly authorized issued, executed and delivered by the Company and is the
valid and binding obligation of the Company, enforceable in accordance with its
terms.

            (b) The shares of Preferred Stock issuable upon the exercise of this
Warrant have been duly authorized and reserved for issuance by the Company and,
when issued in accordance with the terms hereof, will be validly issued, fully
paid and nonassessable.

            (c) The issuance, execution and delivery of this Warrant do not, and
the issuance of the shares of Preferred Stock upon the exercise of this Warrant
in accordance with the terms hereof will not, (i) violate or contravene the
Certificate or by-laws, or to the Company's knowledge, any law, statute,
regulation, rule, judgment or order applicable to the Company, (ii) violate,
contravene or result in a breach or default under any contract, agreement or
instrument to which the Company is a party or by which the Company or any of its
assets are bound or (iii) require the consent or approval of or the filing of
any notice or registration with any person or entity.

            (d) As long as this Warrant is, or any shares of Preferred Stock
issued upon exercise of this Warrant or any shares of Common Stock issued upon
conversion of such shares of Preferred Stock are, issued and outstanding, the
Company will provide to the Holder the financial and other information described
in that certain Lease Line Schedule No. 01 to Master Equipment Lease Agreement
No. 219 between the Company and Lighthouse Capital Partners II, L.P. dated as of
May 5, 1999.

            (e) As of the date hereof, the authorized capital stock of the
Company consists of (i) 19,000,000 shares of Common Stock, none of which are
issued and outstanding and 21,539 shares are reserved for issuance upon the
exercise of this Warrant and the conversion of the Preferred Stock, (ii)
5,686,573 shares of Series A Preferred Stock, all of which are issued and
outstanding, and (iii) 4,130,000 shares of Series B Preferred Stock, of which
3,970,000 are issued and outstanding shares and 21,539 shares are reserved for
issuance upon the exercise of this Warrant. Attached hereto as EXHIBIT C is a
capitalization table summarizing the capitalization of the Company, including,
without limitation, the current Conversion Price of the Series B Preferred
Stock.

        15. INVESTORS' RIGHTS AGREEMENT. The Company agrees that, upon the next
amendment of that certain Investors' Rights Agreement by and among the Company,
the Investors and the Founders listed therein dated as of December 17, 1998 (the
"INVESTORS' RIGHTS AGREEMENT"), it will use its best efforts to effect such
amendment so that the Holder shall be an Investor within the meaning of such
Investors' Rights Agreement.

        16. RIGHT OF FIRST REFUSAL. Subject to the terms and conditions
contained in this SECTION 16, the Company agrees that the holder of this Warrant
has the right of first refusal to purchase its pro rata portion of any New
Securities (as defined in SECTION 16(a) below) which the Company may, from time
to time, propose to sell and issue. A holder's pro rata portion for purposes of
this SECTION 16 is the ratio that (x) the sum of the number of shares of the
Company's Common Stock then issued or issuable to the holder (including upon
conversion of any Preferred Stock held by the holder and upon exercise of this
Warrant and conversion of the Shares issued thereupon) bears to (y) the sum of
the total number of shares of Company's Common Stock then outstanding, the
number of shares of the Company's Common Stock issuable upon conversion of the
Preferred Stock then outstanding, and the number of shares of the Company's
Common Stock issuable to the holder upon exercise of this Warrant and conversion
of the Shares issued thereupon.

            (a) DEFINITION OF NEW SECURITIES. Except as set forth below, "NEW
SECURITIES" shall mean any shares of capital stock of the Company, including
Common Stock and Preferred Stock, whether now authorized or not, and rights,
options or warrants to purchase said shares of Common Stock or Preferred Stock,
and securities of any type whatsoever that are, or may become, convertible into
or exercisable for said shares of Common Stock or Preferred Stock.
Notwithstanding the foregoing, "New Securities" does not include: (i) Common
Stock issuable upon conversion of any Preferred Stock outstanding as of the
grant date; (ii) securities offered to the public generally pursuant to a
registration statement under the Securities Act; (iii) securities issued
pursuant to the

                                       4.
<PAGE>   67

acquisition of another corporation by the Company by merger, purchase of
substantially all of the assets or shares or other reorganization; (iv) shares
of the Company's Common Stock or related options convertible into or exercisable
for such Common Stock issued to employees, officers and directors of, and
consultants to, the Company, pursuant to any compensatory benefit plan; (v)
stock issued pursuant to any rights or agreements, including, without
limitation, convertible securities, options and warrants, provided that the
Company shall have complied with the right of first refusal established by this
SECTION 16 with respect to the initial sale or grant by the Company of such
rights or agreements; or (vi) stock issued in connection with any stock split,
reverse stock split, stock dividend, combination or recapitalization by the
Company.

            (b) NOTICE OF RIGHT. In the event the Company proposes to undertake
an issuance of New Securities, it shall give the holder written notice of its
intention, describing the type of New Securities and the price and terms upon
which the Company proposes to issue the same. The holder shall have fifteen (15)
days from the date of receipt of any such notice to agree to purchase shares of
such New Securities (up to the amount referred to in this SECTION 16), for the
price and upon the terms specified in the notice, by giving written notice to
the Company and stating therein the quantity of New Securities to be purchased.

            (c) EXERCISE OF RIGHT. If the holder exercises its right of first
refusal hereunder, the closing of the purchase of the New Securities with
respect to which such right has been exercised shall take place within ninety
(90) calendar days after the holder gives notice of such exercise, which period
of time shall be extended in order to comply with applicable laws and
regulations. Upon exercise of such right of first refusal, the Company and the
holder shall be legally obligated to consummate the purchase contemplated
thereby and shall use their best efforts to secure any approvals required in
connection therewith.

            (d) LAPSE AND REINSTATEMENT OF RIGHT. In the event the holder fails
to exercise the right of first refusal provided in this SECTION 16 within said
fifteen (15) day period, the Company shall have ninety (90) days thereafter to
sell or enter into an agreement (pursuant to which the sale of New Securities
covered thereby shall be closed, if at all, within sixty (60) days from the date
of said agreement) to sell the New Securities not elected to be purchased by the
holder at the price and upon the terms no more favorable to the purchasers of
such securities than specified in the Company's notice. In the event the Company
has not sold the New Securities or entered into an agreement to sell the New
Securities within said ninety (90) day period (or sold and issued New Securities
in accordance with the foregoing within sixty (60) days from the date of said
agreement), the Company shall not thereafter issue or sell any New Securities
without first offering such securities to the holder in the manner provided
above.

            (e) ASSIGNMENT. The right of the holder to purchase any part of the
New Securities may be assigned in whole or in part to any partner, subsidiary,
affiliate or shareholder of the holder.

            (f) TERMINATION OF RIGHT OF FIRST REFUSAL. The right of first
refusal granted under SECTION 16 shall terminate on and be of no further force
or effect upon the closing of a firmly underwritten public offering of the
securities of the Company.

        17. AMENDMENT. The terms of this Warrant may be amended, modified or
waived only with the written consent of the Holder and the Company.

        18. REPRESENTATIONS AND COVENANTS OF THE HOLDER. This Preferred Stock
Purchase Warrant has been entered into by the Company in reliance upon the
following representations and covenants of the Holder, which by its execution
hereof the Holder hereby confirms:

            (a) INVESTMENT PURPOSE. The right to acquire Preferred Stock
issuable upon exercise of the Holder's rights contained herein or Common Stock
issuable upon conversion thereof (the "CONVERSION SHARES") will be acquired for
investment and not with a view to the sale or distribution of any part thereof,
and the Holder has no present intention of selling or engaging in any public
distribution of the same except pursuant to a registration or exemption. The
Holder further represents that such Holder does not have any contract,
undertaking, agreement or arrangement with any person to sell, transfer, or
grant participations to such person or to any third person, with respect to any
of the Preferred Stock or Conversion Shares.

                                       5.
<PAGE>   68

            (b) ACCREDITED INVESTOR. Holder is an "accredited investor" within
the meaning of the Securities and Exchange Rule 501 of Regulation D, as
presently in effect.

            (c) PRIVATE ISSUE. The Holder understands (i) that the Preferred
Stock issuable upon exercise of the Holder's rights contained herein and the
Conversion Shares is not registered under the 1933 Act or qualified under
applicable state securities laws on the ground that the issuance contemplated by
this Warrant will be exempt from the registration and qualifications
requirements thereof, and (ii) that the Company's reliance on such exemption is
predicated on the representations set forth in this SECTION 18.

            (d) FINANCIAL RISK. The Holder is an investor in securities of
companies in the development stage and has such knowledge and experience in
financial and business matters as to be capable of evaluating the merits and
risks of its investment and has the ability to bear the economic risks of its
investment.

            (e) DISCLOSURE OF INFORMATION. The Holder believes it has received
all the information it considers necessary or appropriate for deciding whether
to purchase the Warrant and the Preferred Stock issuable upon exercise thereof.
Such Holder further represents that it has had the opportunity to ask questions
and receive answers from the Company regarding the terms and conditions of the
Preferred Stock and the business, properties, prospects and financial condition
of the Company.

        19. NOTICES, TRANSFERS, ETC.

            (a) Any notice or written communication required or permitted to be
given to the Holder may be given by certified mail or delivered to the Holder at
the address most recently provided by the Holder to the Company.

            (b) Subject to compliance with applicable federal and state
securities laws, this Warrant may be transferred by the Holder with respect to
any or all of the shares purchasable hereunder. Upon surrender of this Warrant
to the Company, together with the assignment notice annexed hereto duly
executed, for transfer of this Warrant as an entirety by the Holder, the Company
shall issue a new warrant of the same denomination to the assignee. Upon
surrender of this Warrant to the Company, together with the assignment hereof
properly endorsed, by the Holder for transfer with respect to a portion of the
shares of Preferred Stock purchasable hereunder, the Company shall issue a new
warrant to the assignee, in such denomination as shall be requested by the
Holder hereof, and shall issue to such Holder a new warrant covering the number
of shares in respect of which this Warrant shall not have been transferred.

            (c) In case this Warrant shall be mutilated, lost, stolen or
destroyed, the Company shall issue a new warrant of like tenor and denomination
and deliver the same (i) in exchange and substitution for and upon surrender and
cancellation of any mutilated Warrant, or (ii) in lieu of any Warrant lost,
stolen or destroyed, upon receipt of an affidavit of the Holder or other
evidence reasonably satisfactory to the Company of the loss, theft or
destruction of such Warrant

        20. NO IMPAIRMENT. The Company will not, by amendment of its Certificate
or through any reclassification, capital reorganization, consolidation, merger,
sale or conveyance of assets, dissolution, liquidation, issue or sale of
securities or any other voluntary action, avoid or seek to avoid the observance
of performance of any of the terms of this Warrant, but will at all times in
good faith assist in the carrying out of all such terms and in the taking of all
such action as may be necessary or appropriate in order to protect the rights of
the Holder.

        21. GOVERNING LAW. The provisions and terms of this Warrant shall be
governed by and construed in accordance with the internal laws of the State of
California.

        22. SUCCESSORS AND ASSIGNS. This Warrant shall be binding upon the
Company's successors and assigns and shall inure to the benefit of the Holder's
successors, legal representatives and permitted assigns.

        23. BUSINESS DAYS. If the last or appointed day for the taking of any
action required or the expiration of any rights granted herein shall be a
Saturday or Sunday or a legal holiday in California, then such action may be

                                       6.
<PAGE>   69

        taken or right may be exercised on the next succeeding day which is not
a Saturday or Sunday or such a legal holiday.

        24. QUALIFYING PUBLIC OFFERING. If the Company shall effect a firm
commitment underwritten public offering of shares of Common Stock which results
in the conversion of the Preferred Stock into Common Stock pursuant to the
Certificate in effect immediately prior to such offering, then, effective upon
such conversion, this Warrant shall change from the right to purchase shares of
Preferred Stock to the right to purchase shares of Common Stock, and the Holder
shall thereupon have the right to purchase, at a total price equal to that
payable upon the exercise of this Warrant in full, the number of shares of
Common Stock which would have been receivable by the Holder upon the exercise of
this Warrant for shares of Preferred Stock immediately prior to such conversion
of such shares of Preferred Stock into shares of Common Stock, and in such event
appropriate provisions shall be made with respect to the rights and interest of
the Holder to the end that the provisions hereof (including, without limitation,
the provisions for the adjustment of the Purchase Price and of the number of
shares purchasable upon exercise of this Warrant and the provisions relating to
the net issue election) shall thereafter be applicable to any shares of Common
Stock deliverable upon the exercise hereof.

        25. VALUE. The Company and the Holder agree that the value of this
Warrant on the date of grant is $100.

Dated:  May __, 1999                       CHEMCONNECT, INC.

                                           By: /s/ PHILIP J. RINGO
                                              ------------------------------
                                           Name: Phil J. Ringo
                                                 ------------------------------
                                           Title: President and COO
                                                  -----------------------------

        [CORPORATE SEAL]

Attest:

---------------------------------

                                       7.
<PAGE>   70

                                  SUBSCRIPTION

To: ___________________________________________________     Date:______________

        The undersigned hereby subscribes for ____________ shares of Preferred
Stock covered by this Warrant. The certificate(s) for such shares shall be
issued in the name of the undersigned or as otherwise indicated below:

                                      Signature:
                                                -------------------------------

                                      Name for Registration:
                                                            -------------------

                                      Mailing Address:
                                                      -------------------------

                                      -----------------------------------------

                            NET ISSUE ELECTION NOTICE

To: ___________________________________________________     Date:______________

        The undersigned hereby elects under SECTION 4 to surrender the right to
purchase __________ shares of Preferred Stock pursuant to this Warrant. The
certificate(s) for such shares issuable upon such net issue election shall be
issued in the name of the undersigned or as otherwise indicated below:

                                      Signature:
                                                -------------------------------

                                      Name for Registration:
                                                            -------------------

                                      Mailing Address:
                                                      -------------------------

                                      -----------------------------------------

<PAGE>   71

                                   ASSIGNMENT

        For value received ______________________________ hereby sells, assigns
and transfers unto ____________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________

            [Please print or typewrite name and address of Assignee]
________________________________________________________________________________
the within Warrant, and does hereby irrevocably constitute and appoint
____________________________________ its attorney to transfer the within Warrant
on the books of the within named Company with full power of substitution on the
premises.

Dated:_______________________

In the Presence of:

_____________________________

<PAGE>   72

                                    EXHIBIT A

                      RESTATED CERTIFICATE OF INCORPORATION

                               See attached pages.

<PAGE>   73

                                    EXHIBIT B

                              CAPITALIZATION TABLE

                               See attached pages.

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