# Patent

## Title
Process for the production of monohalide or dihalide metallocene compounds

## Abstract

A process for preparing dihalide or monohalide metallocene compounds comprising contacting a compound of formula (II) (Cp)(ZR1m)n(A)rML′y (II) wherein Cp is a cyclopentadienyl radical; (ZR1m)n is a divalent bridging group between Cp and A; A is a cyclopentadienyl radical or O, S, NR2, PR2 wherein R2 is an hydrocarbon radical, M is zirconium, titanium or hafnium. L′ is an hydrocarbon radical, r ranges from 0 to 2 and y is equal to 4; with an halogenating agent selected from the group consisting of: T1Lw1 wherein T1 is a metal of groups 3–13 of the periodic table; L is halogen and w1 is equal to the oxidation state of the metal T1; T2Lw2 wherein T2 is a nonmetal element of groups 13–16 of the periodic table (new IUPAC version); and w2 is equal to the oxidation state of the element T2; O=T3Lw3 where T3 is a selected from the group consisting of C, P and S; O is an oxygen atom bonded to T3 through a double bond; and w3 is equal to the oxidation state of the element T3 minus 2; R6C(O)L, wherein R6 is an hydrocarbon radical; L2 and HL.

## Background
The present invention relates to a process for the production of monohalide or dihalide metallocene compounds in high purity and in high yields.
Metallocene compounds are well known in the art as catalyst components for the polymerization of olefins. For instance, the European Patent Application EP 0 129 368 discloses catalysts comprising mono- and di-cyclopentadienyl coordination complexes with a transition metal in combination with an alumoxane.
In those metallocene compounds, the central metal is coordinated with one or more π-bonded ligands, usually cyclopentadienyl moieties, and with one or more sigma-bonded ligands. The latter are usually halogen, preferably chlorine. In the usual process for preparing dihalide metallocene compounds the lithium salts of the ligands are contacted with a tetrahalide of the metal. This process generates LiCl as a by-product that is difficult to separate because of the low solubility of the dihalide metallocene compounds in the usual solvents, and often the yield of the process is not satisfactory.
For instance, F. Wild et al. (J. Organomet. Chem., 288:63–67, 1985) describe the synthesis of chiral ansa-zirconocene derivatives with ethylene-bridged ligands. In particular, it is reported the preparation of ethylene-bis(1-indenyl)zirconium dichloride by reaction of the dilithium salt of bis(1-indenyl)ethane with ZrCl4, in a yield of about 35%. Better results have been obtained by I. M. Lee et al. (Organometallics, 11:2115–2122, 1992), who prepared ethylene-bis(1-indenyl)zirconium dichloride in a yield of 52%. Another example can be found in Polyhedron 1990, 9, 301 wherein it is reported the synthesis of bis(indenyl)zirconium dichloride starting from indene and zirconium tetrachloride with a final yield of 58%.
In Izv. Akad. Nauk SSSR, Ser. Khim. 1976, 2621 there is described a reaction of mercury chloride (HgCl2) with bis(cylopentadienyl)zirconium dibenzyl. In this paper it is shown that, instead of the expected bis(cylopentadienyl)zirconium dichloride, the reaction product is the complex (C5H5)2ZrCl2x3C6H5CH2HgCl.
In Dokl. Akad. Nauk SSSR (1976), 231(1), 114–15, G. A. Razuvaev investigates the mechanism of photo or thermo demethylation and dearylation by using bis(cylopentadienyl)zirconium dimethyl or dibenzyl and carbon tetrachloride or chloroform. The reaction is slow (about 100 h at 150° C. for the thermodemethylation) and moreover the yields are rather low.
A process for obtaining bis(cylopentadienyl)zirconium chloride methyl has been described by Wailes in Journal of Organometallic Chemistry 1972, 34, 155. According to this process, bis(cyclopentadienyl)zirconium chloride methyl is obtained by reacting the dimethyl derivative with PbCl2. The yield of this process is not reported. The applicant by running a test according to the process described by Wailes (reported as comparative example 11) has found that that the yield of this process is not satisfactory for an industrial process.
Therefore it is felt the need for a simpler and more convenient and practical method to produce the above metallocene derivatives in satisfactory yields.
This need is fulfilled according to the present invention that, according to a first object, relates to a process for preparing dihalide or monohalide metallocene compounds of formula (I):

(Cp)(ZR1m)n(A)rMLqL′s  (I)

wherein (ZR1m)n is a divalent group bridging the Cp and A moieties; Z being C, Si, Ge, N or P, and the R1 groups, equal to or different from each other, being hydrogen or linear or branched, saturated or unsaturated C1–C20 alkyl, C3–C20 cycloalkyl, C6–C20 aryl, C7–C20 alkylaryl or C7–C20 arylalkyl groups, optionally containing one or more heteroatoms belonging to groups 13–17 of the Periodic Table of the Elements, or two R1 can form an aliphatic or aromatic C4–C7 ring that can bear substituents;

    Cp is an unsubstituted or substituted cyclopentadienyl group, optionally condensed to one or more unsubstituted or substituted, saturated, unsaturated or aromatic rings, containing from 4 to 6 carbon atoms, optionally containing one or more heteroatoms belonging to groups 13–17 of the Periodic Table of the Elements;
    A is O, S, NR2 or PR2, R2 being hydrogen, a linear or branched, saturated or unsaturated C1–C20 alkyl, C3–C20 cycloalkyl, C6–C20 aryl, C7–C20 alkylaryl or C7–C20 arylalkyl, or A has the same meaning of Cp;
    M is zirconium, titanium or hafnium, preferably being zirconium or hafnium;
    the L substituents, equal to or different from each other, preferably equal, are chlorine, bromine, iodine, preferably chlorine;
    L′ is selected from the group consisting of hydrogen, a linear or branched, saturated or unsaturated C1–C20 allyl, C3–C20 cycloalkyl, Q-C2-0 aryl, C7–C20 alkylaryl or C7–C20 arylalkyl group, optionally containing one or more Si or Ge atoms; preferably L′ is methyl, ethyl, n-butyl, sec-butyl, phenyl, benzyl or —CH2Si(CH3)3; more preferably L′ is methyl;
    m is 1 or 2 depending on the oxidation state of Z, more specifically it is 1 when Z is N or P, and it is 2 when Z is C, Si or Ge;
    n is 0, 1, 2, 3 or 4, preferably it is 0, 1 or 2; being 0 when r is 0 or 2;
    r is 0, 1 or 2, preferably being 0 or 1;
    q is 1, 2, or 3;
    s is 0 or 1;
    s and q satisfying the following equation: q+s=3-r, preferably q is 1 or 2 and s is 0 or 1; more preferably q is 2 and s is 0;
    said process comprising contacting a compound of formula (II):

(Cp)(ZR1m)n(A)rML′y  (II)

wherein y is equal to s+q and Cp, Z, R1, A, M, L′, m, r, n, s and q have the same meaning as above,

    with an halogenating agent selected from the group consisting of T1Lw1, T2Lw2, O=T3Lw3, R6C(O)L, L2 and HL, mercury dichloride (HgCl2) being excluded, wherein:
    T1 is a metal of groups 3–13 of the periodic table (new IUPAC version) or of the lanthanides series; preferably T1 is a metal of groups 7–11 of the periodic table (new IUPAC version);
    T2 is a nonmetal element of groups 13–16 of the periodic table (new IUPAC version) with the exclusion of carbon;
    T3 is selected from the group consisting of C, P and S;
    O is an oxygen atom bonded to T3 through a double bond;
    R6 is selected from a linear or branched, saturated or unsaturated C1–C20 allyl, C3–C20 cycloalkyl, C6–C20 aryl, C7–C20 alkylaryl or C7–C20 arylalkyl;
    L has the same meaning as above;
    H is hydrogen;
    w1 is equal to the oxidation state of the metal T1;
    w2 is equal to the oxidation state of the element T2;
    w3 is equal to the oxidation state of the element T3 minus 2.


The compound of formula (II) are well know in the art for example they can be easily prepared as described in WO 99/36427 or WO 00/75151.
An alternative embodiment for preparing dihalide or monohalide metallocene compounds of formula (I) starting directly from the ligand without isolating the compound of formula (II) comprises the following steps:

    a) reacting a ligand of formula (Y-Cp) (ZR1m)n(AY)r or when n is 0 a mixture of ligands Y-Cp and r(A-Y) with an amount EQ of a compound of formula L′jB or L′MgL′′′ such that EQ≧1+r molar equivalents with respect to Cp, preferably 1+r≦EQ≦1+r+q molar equivalents; more preferably EQ=1+r+q molar equivalents, wherein Cp, A, Z, R1, m, r, q, and L′ have the meaning reported above; L′′′ is selected from the group consisting of chlorine, bromine, iodine; n is an integer having values 1, 2, 3 or 4; the groups Y, the same or different from each other, are suitable leaving groups; Mg is magnesium; B is an alkaline or alkaline-earth metal; and j is 1 or 2, j being equal to 1 when B is an alkali metal, and j being equal to 2 when B is an alkaline-earth metal;
    b) reacting the product obtained from step a) with at least 1 molar equivalent with respect to Cp of a compound of formula ML′′4, wherein M have the meaning reported above, L′′ is selected from the group consisting of chlorine, bromine, iodine;
    c) if the amount EQ of a compound of formula L′jB or L′MgL′′ added in step a) is less than 1+r+q, adding to the reaction mixture an amount of a compound of formula L′jB or L′MgL′′′ equal to or higher than 1+r+q−EQ molar equivalents, preferably equal to 1+r+q−EQ;
    d) optionally purifying the mixture and separating the meso and the rac forms; and
    e) reacting the mixture with an halogenating agent selected from the group consisting of: T1Lw1; T2Lw2; O=T3Lw3; R6C(O)L; L2 and HL wherein T1, T2, T3, L, w1, w2, w3 and R6 have been described above.


When n is different from 0 and r is 1 a preferred process for preparing the dihalide or monohalide of bridged metallocene compounds of formula (III)

(Cp)(ZP1m)n(A)MLqL′s  (III)

wherein M, Cp, A, Z, R1, m, q, s, L and L′ have the meaning reported above and n is an integer having values 1, 2, 3 or 4; comprises the following steps:

    a) reacting a ligand of formula (Y-Cp)(ZR1m)n(A-Y) with at least 2+q molar equivalents with respect to Cp, of a compound of formula L′jB or L′MgL′′′, wherein Cp, A, Z, R1, m, q, and L′ have the meaning reported above; L′′′ is selected from the group consisting of chlorine, bromine, iodine; n is an integer having values 1, 2, 3 or 4; the groups Y, the same or different from each other, are suitable leaving groups; Mg is magnesium; B is an alkaline or alkaline-earth metal; and j is 1 or 2, j being equal to 1 when B is an alkali metal, and j being equal to 2 when B is an alkaline earth metal; and
    b) reacting the product obtained from step a) with at least 1 molar equivalent of a compound of formula ML′′4, wherein M have the meaning reported above, L′′ is selected from the group consisting of chlorine, bromine, iodine;
    
        c) optionally purifying the mixture and separating the racemic and the meso forms;
        d) reacting the mixture with an halogenating agent selected from the group consisting of: T1Lw1; T2Lw2; O=T3Lw3; R6C(O)L; L2 and HL wherein T1, T2, T3, L, w1, w2, w3 and R6 have been described above.
    
    


When A is equal to Cp and n is equal to 0 a preferred process for preparing metallocene compounds of formula (IV)

(Cp)(Cp)rMLqL′s  (IV)

wherein M, Cp, M, L, L′, r, q and s have been described above comprises the following steps:

    a) reacting 1+r molar equivalent of a ligand of formula (Y-Cp) with at least 3+r molar equivalents of a compound of formula LjB or L′′′MgL′, wherein Cp, L′′′ and L′ have the meaning reported above; the groups Y, the same or different from each other, are suitable leaving groups; B is an alkaline or alkaline-earth metal; and j is 1 or 2, j being equal to 1 when B is an alkali metal, and j being equal to 2 when B is an alkaline-earth metal;
    b) reacting the product obtained from step a) with at least 1 molar equivalent of a compound of formula ML′′4, wherein M have the meaning reported above, L′′ is selected from the group consisting of chlorine, bromine, iodine;
    c) optionally purifying the mixture; and
    d) reacting the mixture with an halogenating agent selected from the group consisting of: T1Lw1; T2Lw2; O=T3Lw3; R6C(O)L; L2 and HL wherein T1, T2, T3, L, w1, w2, w3, R6 have been described above.


According to a preferred embodiment of the present invention, all the reactions of the above processes are carried out in an aprotic solvent, either polar or apolar. Said aprotic solvent is preferably an aromatic or aliphatic hydrocarbon, optionally halogenated, or an ether, more preferably it is selected from the group consisting of benzene, toluene, pentane, hexane, heptane, cyclohexane, dichloromethane, diethylether, tetrahydrofurane or mixtures thereof.
The amount of the halogenating agent to be used depends from the type of compound. As a rule, for obtaining a monohalide metallocene compounds at least half molar equivalent with respect to the halogen atom has to be used, while for obtaining a dihalide derivative at least one molar equivalent with respect to the halogen atom has to be used. Excess of halogenating agent can also be used.
The Y leaving group is preferably hydrogen.
The ML′′4 reactant, is preferably selected from the group consisting of TiCl4, ZrCl4, HfCl4. It can be used even in the form of a stabilized derivative, such as an etherate complex of ML′′4, easily available on the market.
The compounds L′jB and L′′′MgL′ are alkylating agents. Preferably L′ is selected from the group consisting of methyl, ethyl, n-butyl, sec-butyl, phenyl, benzyl and —CH2Si(CH3)3. More preferably L′ is methyl.
In the compound LjB, B is an alkali or alkaline-earth metal, preferably Li or Mg; j can be 1 or 2, as already reported.
The compound L′′′MgL′ is a Grignard reagent, wherein Mg is magnesium and L′′′ and L′ have the meanings reported above. L′′′ is preferably bromine or iodine.
According to a preferred embodiment of the process of the invention, said alkylating agent is methyllithium.
Preferably in the processes for preparing compounds of formula (I), (III) and (IV) in step (a), the ligands are previously dissolved in an aprotic polar solvent and to the resulting solution is added the alkylating agent L′jB or L′′′MgL′. This addition is preferably carried out at a temperature ranging from −100° C. to +80° C., more preferably from −80° C. to +10° C., over a period of 5 to 45 minutes, more preferably of 10 to 20 minutes. The alkylating agent is preferably added in the form of a solution in one of the above mentioned aprotic solvents, preferably dropwise.
The thus obtained reaction mixture is preferably allowed to react, under stirring, for a period ranging from 1 to 6 hours, more preferably from 2 to 3 hours, at a temperature comprised between −10° C. and +80° C., more preferably at room temperature.
Before the reaction with ML′′4, in step (b), the mixture obtained from step (a) is preferably cooled to a temperature ranging from −100° C. to +80° C., more preferably from −80° C. to +70° C. Then ML′′4 is quickly added to the cooled slurry in the form of a solution in one of the above mentioned aprotic solvents, preferably pentane, hexane, heptane or toluene.
The reaction mixture is then allowed to react for a period ranging from 10 minutes to 36 hours, more preferably from 1 to 18 hours, at a temperature comprised between −100° C. and +80° C., more preferably between −50° C. and +50° C., even more preferably at room temperature.
In the halogenating step the temperature ranges from −50° C. to +150° C., preferably from 0° C. to 100° C., more preferably from 20° C. to 50° C. The halogenating agent is generally added dropwise and then the reaction mixture is preferably allowed to react, under stirring, for a period ranging from 1 to 6 hours, more preferably from 2 to 3 hours, at a temperature comprised between −10° C. and +80° C., more preferably at room temperature.
The thus obtained metallocene compounds of formulas (I), (III) and (IV) can be isolated according to the common procedures known in the state of the art.
Non limiting examples of halogenating agents of formula T1Lw1 are: FeCl3, CuCl2 and ZnCl2.
Non limiting examples of halogenating agents of formula T2Lw2 are: BCl3, BBr3, SiCl4 and PCl5.
Non limiting examples of halogenating agents of formula O=T3Lw3 are: SOCl2 and POCl3.
Non limiting examples of halogenating agents of formula R6C(O)L are: CH3C(O)Cl, C6H5CH2C(O)Cl, C6H5C(O)Cl and CH3CH2CH2C(O)Cl.
Non limiting examples of halogenating agents of formula L2 are: Br2, Cl2 and I2.
Non limiting examples of halogenating agents of formula HL are HCl, HBr and HI.
In the optional steps (c) and (d) the purification of the reaction mixture is preferably carried out by simply filtering the solution in order to remove the salts. Also other systems of purification can be used, for example a suitable solvent in order to precipitate the undesired by products can be added with subsequently filtration. In these steps it is also possible to separate (when present) the racemic and the meso form by using methods known in the art. For example, by using suitable solvents it is possible to precipitate one form with subsequently filtration. All the operations are carried out in inert atmosphere.
In the metallocenes of formula (I) and (III), the divalent bridge (ZR1m)n is preferably selected from the group consisting of CR12, (CR12)2, (CR12)3, SiR12, GeR12, NR1 and PR1, R1 having the meaning reported above. More preferably, said divalent bridge is Si(CH3)2, SiPh2, CH2, (CH2)2, (CH2)3 or C(CH3)2.
The variable m is 1 or 2; the variable n ranges from 0 to 4 preferably is 1 or 2, when n>1, the atoms Z can be the same or different from each other, such as in divalent bridges —CH2—O—, —CH2—S— and —CH2—Si(CH3)2—. When n=0 and r=1, A can have only the meaning of Cp.
In the metallocenes of formula (I), (III) and (IV) the ligand Cp, which is π-bonded to said metal M, is preferably selected from the group consisting of cyclopentadienyl, mono-, di-, tri- and tetra-methyl cyclopentadienyl; 4-tertbutyl-cyclopentadienyl; 4-adamantyl-cyclopentadienyl; indenyl; mono-, di-, tri- and tetra-methyl indenyl; 4,5,6,7-tetrahydroindenyl; fluorenyl; 5,10-dihydroindeno[1,2-b]indol-10-yl; N-methyl- or N-phenyl-5,10-dihydroindeno [1,2-b]indol-10-yl; 5,6-dihydroindeno[2,1-b]indol-6-yl; N-methyl- or N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl; azapentalene-4-yl; thiapentalene-4-yl; azapentalene-6-yl; thiapentalene-6-yl; mono-, di- and tri-methyl-azapentalene-4-yl and 2,5-dimethyl-cyclopenta[1,2-b:4,3-b′]-dithiophene.
The group A has preferably the same meaning of Cp, or it is N-methyl, N-ethyl, N-isopropyl, N-butyl, N-phenyl, N-benzyl, N-cyclohexyl and N-cyclododecyl.
Non limiting examples of metallocene compounds of formula (I), (III) and (IV) are the racemic and the meso form (when present) of the following compounds:

    bis(cyclopentadienyl)zirconium dichloride;
    bis(indenyl)zirconium dichloride;
    bis(tetrahydroindenyl)zirconium dichloride;
    bis(fluorenyl)zirconium dichloride;
    dimethylsilanediylbis(indenyl)zirconium dichloride,
    dimethylsilanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride,
    dimethylsilanediylbis(4-naphthylindenyl)zirconium dichloride,
    dimethylsilanediylbis(2-methylindenyl)zirconium dichloride,
    dimethylsilanediylbis(2-methyl-(4-t-butyl-phenyl) indenyl)zirconium dichloride,
    dimethylsilanediylbis(2-methyl-4-isopropylindenyl)zirconium dichloride,
    dimethylsilanediylbis(2,4-dimethylindenyl)zirconium dichloride,
    dimethylsilanediylbis(2-methyl-4,5-benzoindenyl)zirconium dichloride,
    dimethylsilanediylbis(2,4,7-trimethylindenyl)zirconium dichloride,
    dimethylsilanediylbis(2,4,6-trimethylindenyl)zirconium dichloride,
    dimethylsilanediylbis(2,5,6-trimethylindenyl)zirconium dichloride,
    methyl(phenyl)silanediylbis(2-methyl-4,6-diisopropylindenyl)-zirconium dichloride,
    methyl(phenyl)silanediylbis(2-methyl-4-isopropylindenyl)-zirconium dichloride,
    1,3-propylenebis(indenyl)zirconium dichloride,
    1,3-propylenebis(4,7-dimethylindenyl)zirconium dichloride,
    1,3-propylenebis(2-methyl-4-phenylindenyl)zirconium dichloride,
    1,3-propylenebis(2-methyl-4,6-diisopropylindenyl)zirconium dichloride,
    1,3-propylenebis (2-methyl-4,5-benzoindenyl)zirconium dichloride,
    1,2-ethylenebis(indenyl)zirconium dichloride,
    1,2-ethylenebis(4,7-dimethylindenyl)zirconium dichloride,
    1,2-ethylenebis(2-methyl-4-phenylindenyl)zirconium dichloride,
    1,4-butanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride,
    1,2-ethylenebis(2-methyl-4,6-diisopropylindenyl)zirconium dichloride,
    1,4-butanediylbis(2-methyl-4-isopropylindenyl)zirconium dichloride,
    1,4-butanediylbis(2-methyl-4,5-benzoindenyl)zirconium dichloride,
    1,2-ethylenebis (2-methyl-4,5-benzoindenyl)zirconium dichloride,
    [4-(η5-cyclopentadienyl)-4,6,6-trimethyl(η5-4,5-tetrahydropentalene)]dichloridezirconium,
    [4-(η5-3′-trimethylsilylcyclopentadienyl)-4,6,6-trimethyl(η5-4,5-tetrahydropentalene)]dichloridezirconium,
    (tert-butylamido)(tetramethyl-η5-cyclopentadienyl)-1,2-ethane-dichloridetitanium,
    (methylamido)(tetramethyl-η5-cyclopentadienyl)dimethylsilyl-dichloridetitanium,
    (methylamido)(tetramethyl-η5-cyclopentadienyl)-1,2-ethanediyl-dichloridetitanium,
    (tertbutylamido)-(2,4-dimethyl-2,4-pentadien-1-yl)dimethylsilyl-dichloridetitanium,
    bis(1,3-dimethylcyclopentadienyl)zirconium dichloride,
    methylene(3-methyl-cyclopentadienyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    methylene(3-isopropyl-cyclopentadienyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    methylene(2,4-dimethyl-cyclopentadienyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    methylene(2,3,5-trimethyl-cyclopentadienyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    methylene-1-(indenyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    methylene-1-indenyl)-7-2,5-ditrimethylsilylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    methylene-1-(3-isopropyl-indenyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    methylene-1-(2-methyl-indenyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    methylene-1-(tetrahydroindenyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    methylene(2,4-dimethyl-cyclopentadienyl)-7-2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dioxazol)zirconium dichloride;
    methylene(2,3,5-trimethyl-cyclopentadienyl)-7-2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dioxazol)zirconium dichloride;
    methylene-1-(indenyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dioxazol)zirconium dichloride;
    isopropylidene(3-methyl-cyclopentadienyl)-7-2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′) dithiophene)zirconium dichloride;
    isopropylidene(2,4-dimethyl-cyclopentadienyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′] dithiophene)zirconium dichloride;
    isopropylidene(2,4-diethyl-cyclopentadienyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    isopropylidene(2,3,5-trimethyl-cyclopentadienyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    isopropylidene-1-(indenyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    isopropylidene-1-(2-methyl-indenyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)zirconium dichloride;
    dimethylsilandiyl-1-(2-methyl-indenyl)-7-(2,5-dimethylcyclopentadienyl-[1,2-b:4,3-b′]dithiophene)hafnium dichloride;
    dimethylsilanediyl(3-tert-butyl-cyclopentadienyl)(9-fluorenyl)zirconium dichloride,
    dimethylsilanediyl(3-isopropyl-cyclopentadienyl)(9-fluorenyl)zirconium dichloride,
    dimethylsilanediyl(3-methyl-cyclopentadienyl)(9-fluorenyl)zirconium dichloride,
    dimethylsilanediyl(3-ethyl-cyclopentadienyl)(9-fluorenyl)zirconium dichloride,
    1-2-ethane(3-tert-butyl-cyclopentadienyl)(9-fluorenyl)zirconium dichloride,
    1-2-ethane (3-isopropyl-cyclopentadienyl)(9-fluorenyl)zirconium dichloride,
    1-2-ethane (3-methyl-cyclopentadienyl)(9-fluorenyl)zirconium dichloride,
    1-2-ethane (3-ethyl-cyclopentadienyl)(9-fluorenyl)zirconium dichloride,
    dimethylsilandiylbis-6-(3-methylcyclopentadienyl-[1,2-b]-thiophene) zirconium dichloride;
    dimethylsilandiylbis-6-(4-methylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-(4-isopropylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-(4-ter-butylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-(3-isopropylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-(3-phenylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-(2,5-dimethyl-3-phenylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-[2,5-dimethyl-3-(2-methylphenyl)cyclopentadienyl-(1,2-b]-thiophene]zirconium dichloride;
    dimethylsilandiylbis-6-[2,5-ethyl-3-(2,4,6-trimethylphenyl)cyclopentadienyl-[1,2-b]-thiophene]zirconium dichloride;
    dimethylsilandiylbis-6-[2,5-dimethyl-3-mesitylenecyclopentadienyl-[1,2-b]-thiophene]zirconium dichloride;
    dimethylsilandiylbis-6-(2,4,5-trimethyl-3-phenylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-(2,5-diethyl-3-phenylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-(2,5-diisopropyl-3-phenylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-(2,5-diter-butyl-3-phenylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-(2,5-ditrimethylsilyl-3-phenylcyclopentadienyl-[1,2-b]-thiophene)zirconium dichloride;
    dimethylsilandiylbis-6-(3-methylcyclopentadienyl-[1,2-b]-silole)zirconium dichloride;
    dimethylsilandiylbis-6-(3-isopropylcyclopentadienyl-[1,2-b]-silole)zirconium dichloride;
    dimethylsilandiylbis-6-(3-phenylcyclopentadienyl-[1,2-b]-silole)zirconium dichloride;
    dimethylsilandiylbis-6-(2,5-dimethyl-3-phenylcyclopentadienyl-[1,2-b]-silole)zirconium dichloride;
    dimethylsilandiylbis-6-[2,5-dimethyl-3-2-methylphenyl)cyclopentadienyl-[1,2-b]-silole]zirconium dichloride;
    dimethylsilandiylbis-6-[2,5-dimethyl-3-(2,4,6-trimethylphenyl)cyclopentadienyl-[1,2-b]-silole]zirconium dichloride;
    dimethylsilandiylbis-6-[2,5-dimethyl-3-mesitylenecyclopentadienyl-[1,2-b]-silole]zirconium dichloride;
    dimethylsilandiylbis-6-(2,4,5-trimethyl-3-phenylcyclopentadienyl-[1,2-b]-silole)zirconium dichloride;
    [dimethylsilyl(tert-butylamido)][(N-methyl-1,2-dihydrocyclopenta[2,1-b]indol-2-yl)]titanium dichloride;
    [dimethylsilyl(tert-butylamido)][(6-methyl-N-methyl-1,2-dihydrocyclopenta[2,1-b]indol-2-yl)]titanium dichloride;
    [dimethylsilyl(tert-butylamido)][(6-methoxy-N-methyl-1,2-dihydrocyclopenta[2,1-b]indol-2-yl)]titanium dichloride;
    [dimethylsilyl(tert-butylamido)][(N-ethyl-1,2-dihydrocyclopenta[2,1-b]indol2-yl)]titanium dichloride;
    [dimethylsilyl(tert-butylamido)][(N-phenyl-1,2-dihydrocyclopenta[2,1-b]indol2-yl)]titanium dichloride;
    [dimethylsilyl(tert-butylamido)][(6-methyl-N-phenyl-1,2-dihydrocyclopenta[2,1-b]indol2-yl)]titanium dichloride;
    [dimethylsilyl(tert-butylamido)][(6-methoxy-N-phenyl-1,2-dihydrocyclopenta[2,1-b]indol2-yl)]titanium dichloride;
    [dimethylsilyl(tert-butylamido)][(N-methyl-3,4-dimethyl-1,2-dihydrocyclopenta[2,1-b]indol-2-yl)]titanium dichloride;
    [dimethylsilyl(tert-butylamido)][(N-thyl-3,4-dimethyl-1,2-dihydrocyclopenta[2,1-b]indol-2-yl)]titanium dichloride;
    [dimethylsilyl(tert-butylamido)][(N-phenyl-3,4-dimethyl-1,2-dihydroclopenta[2,1-b]indol-2-yl)]titanium dichloride;

as well as the correspondent titanium and hafnium compounds and the dibromide and diodide compounds.



The process according to the present inventions shows several advantages with respect to the processes generally known in the state of the art. The overall yields starting from the ligands are generally higher than those reported in the art. Moreover, it is easier to purify the desired product, due to the better solubility of the formed intermediate alkylated metallocene with respect to the dihalide or monohalide product. Further, because of the higher solubility of said intermediate metallocene it is also easy to separate the racemic and the meso form at this step and thus to obtain the substantially pure racemic or meso form as the final product.
The metallocene compounds obtained with the process according to the present invention, in combination with a suitable activator such as an alumoxane, can be used as a catalyst for the polymerization of olefins. Particularly, they can be used for the homo or co-polymerization of alpha-olefins of formula CH2═CHR wherein R is hydrogen or a C1–C20 alkyl, such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene.
An interesting use is for the production of isotactic, syndiotactic or atactic polypropylene. Another interesting use is for the copolymerization of ethylene with alpha-olefins, such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene, with cycloolefins, such as cyclopentene, cyclohexene, norbornene and 4,6-dimethyl-1-heptene, or with polyenes, such as 1,4-hexadiene, isoprene, 1,3-butadiene, 1,5-hexadiene and 1,6-heptadiene.
Further, they can be advantageously used in olefin oligomerization or hydrogenation reactions. The above metallocenes form suitable polymerization catalytic systems in association with alumoxanes of formula:




wherein the substituents R3 can be a linear or branched, saturated or unsaturated, C1–C20 alkyl, alkenyl or alkylaryl radical;

or in association with the product obtained by contacting an organometallic aluminum compound of formula AlR53-zHz, wherein R5 can be C1–C10 alkyl, alkenyl or alkylaryl radicals, optionally containing one or more Si or Ge atoms, with water.

Particularly suitable alumoxanes, acting as cocatalysts with the above metallocenes, are methylalumoxane (MAO), tris(2-methyl-propyl)alumoxane (TIB AO) and 2,4,4-trimethyl-pentylalumoxane (TIOAO).
Non-limiting examples of organometalic aluminum compounds that, upon contacting with water, produce suitable cocatalysts are trimethylaluminum (TMA), tris(2,4,4-trimethyl-pentyl)aluminum (TIOA), tris(2-methyl-propyl)aluminum (TIBA), tris(2,3,3-trimethyl-butyl)aluminum, tris(2,3-trimethyl-hexyl)aluminum, tris(2,3-dimethyl-butyl)aluminum, tris(2,3-dimethyl-pentyl)aluminum, tris(2,3-dimethyl-heptyl)aluminum, tris(2-methyl-3-ethyl-pentyl)aluminum and tris(2-ethyl-3,3-dimethyl-butyl).
The above catalysts can suitably be used on inert supports, such as silica, alumina, styrene/divinylbenzene copolymers, polyethylene or polypropylene, particularly for use in the gas phase polymerizations.
The olefin polymerization processes can be carried out in liquid phase, optionally in the presence of an inert hydrocarbon solvent, either aromatic (e.g. toluene) or aliphatic (e.g. propane, hexane, heptane, isobutane, cyclohexane and 2,2,4-trimethylpentane). The polymerization temperature generally ranges from about 0° C. to about 250° C., and preferably from 20 to 150° C.
The following examples are given for illustrative and not limitative purposes.
General Procedures and Characterizations
All operations were performed under nitrogen by using conventional Schlenk-line techniques. Solvents were purified by degassing with N2 and passing over activated (8 hours, N2 purge, 300° C.) Al2O3, and stored under nitrogen. MeLi (Acros), TiCl4 (Aldrich), ZrCl4 (Aldrich), HfCl4 (Roc-Ric, 99.99% Hf), FeCl3 (Aldrich), BCl3 (Aldrich), CuCl (Carlo Erba, RPE-ACS, 95%) and SiCl4 (Aldrich) were used as received. Technical indene (Aldrich) was purified by passing over activated Al2O3; All compounds were analyzed on an AC 200 Bruker spectrometer, by 1H NMR (200.13 MHz, CD2Cl2, referenced against the middle peak of residual CHDCl2 at 5.35 ppm, or C6D6, referenced against the peak of residual C6D5H at 7.15 ppm) and 13C NMR (50.323 MHz, Broad Band Decoupling, C6D6, referenced to the central line of C6D6 at 128.00 ppm). All NMR solvents were dried over P4O10 or CaH2 and distilled before use. GC-MS analyses were carried out on a HP 5890-series 2 gas-chromatograph and a HP 5970 mass spectrometer.


COMPARATIVE EXAMPLE 1
Synthesis of Ind2ZrCl2 
40 mL of a 1.5 M solution of BuLi in Et2O (60 mmol) were added dropwise to 7.0 mL of indene (60.0 mmol) in 20 mL of THF, cooled to −78° C. At the end of the addition, the solution was allowed to warm to room temperature and stirred for 1 hour, to give an orange solution. 7 g of ZrCl4 (30.0 mmol) were dissolved in 30 mL of THF at −78° C. in a 100 mL flask equipped with reflux condenser (exothermic reaction). The mixture was allowed to reach room temperature with stirring, then refluxed for 30 min, to give a clear, brown solution. To this solution was added the THF solution of indenyllithium at room temperature with stirring, then the resulting suspension was stirred for two hours. The color turned yellow. The solvents were removed under reduced pressure, the residue slurried in Et2O and transferred into an extractor, washed with Et2O until colorless, then extracted with CH2Cl2, the extract dried and washed again with Et2O and then pentane, finally dried to give 4.35 g of yellow, analytically pure Ind2ZrCl2. Isolated yield 36.9%.
COMPARATIVE EXAMPLE 2
Synthesis of Ind2ZrCl2 
9.9 mL of a 1.6 M solution of MeLi in Et2O (15.8 mmol) were added dropwise to 1.97 g of technical indene (93.3% by GC, 15.8 mmol) in 30 mL of Et2O, at the end of the addition the mixture was stirred for 40 min at room temp., then it was added at once to 1.84 g of ZrCl4 (7.9 mmol) slurried in 30 mL of pentane, then the resulting suspension was stirred for two hours. The color turned yellow. The product in pentane/Et2O was transferred into an extractor, filtrated, the filtrate was discarded, the residue dried and extracted at reflux with 80 mL of CH2Cl2 for 5 hours. The extract was dried to give 2.08 g of lemon yellow Ind2ZrCl2, containing 4 mol % of Ind2ZrClMe (1H NMR). Isolated yield 67%.
EXAMPLE 3
Synthesis of Ind2ZrCl2 
Synthesis of Ind2ZrMe2.
15.8 ml of a solution of MeLi 1.6 M in Et2O (25.3 mmol) were added at room temperature to a solution of 1.5 g (12.6 mmoles) of indene (Aldrich, 97.9% by G.C.) in 30 ml of Et2O in about 5 minutes (exothermic reaction). The mixture was stirred for 30 min, to give an orange solution. 1.47 g of ZrCl4 (6.33 mmol) were slurried in 30 ml pentane. The ZrCl4 slurry in pentane was quickly added to the Li salt solution in Et2O (exothermic reaction). The reaction mixture was stirred for 30 min, and the yellow-brown suspension was treated as described above, to give 1.92 g (86.5% yield) of a light yellow solid, which was characterized by 1H NMR as spectroscopically pure Ind2ZrMe2.
Anal. Calcd for C20H20Zr: C, 68.32; H, 5.73; Zr, 25.94. Found: C, 67.3; H, 5.75; Cl, <0.05.
1H-NMR (C6D6, δ, ppm): −0.50 (s, Ti—CH3, 6H), 5.37 (t, Cp-H(2), 2H, J=3.24 Hz), 5.78 (d, Cp-H(1,3), 4H, J=3.24 Hz), 6.90–6.95 (m, Ar, 4H), 7.16–7.22 (m, Ar, 4H).
Synthesis of Ind2ZrCl2.
0.33 g of Ind2ZrMe2 (0.94 mmol) were charged in a 10 mL Schlenk tube, and dissolved in 4 mL of CD2Cl2. 0.485 g of CuCl (Carlo Erba, 95%, 4.65 mmol) were added, and the mixture stirred at room temperature for 6 hours, when 1H NMR showed the reaction to be complete. 20 mL of CH2Cl2 were added and the mixture was filtered over a G4 frit The yellow-green solution was brought to dryness to give 0.34 g of yellow-green powder (yield 93%) whose 1H NMR is identical to that of a true sample of Ind2ZrCl2.
1H NMR (CD2Cl2, 8, ppm): 6.23 (d, H(1-3), 4H, J=3.32 Hz), 6.55 (t, H(2), 2H, J=3.32 Hz), 7.28–7.37 (m, Ar, 4H), 7.60–7.69 (m, Ar, 4H).
EXAMPLE 4
Synthesis of Ind2ZrCl2 
2.5 g of indene (92% wt by GC, 19.8 mmol) were dissolved in 30 mL of Et2O in a 250 mL Schlenk tube. 24.8 mL of MeLi 1.6 M in Et2O (39.7 mmol) were added with stirring at room temperature (exothermic reaction). After stirring for 40 min, a yellow-orange solution was obtained, to which was added a suspension of 2.3 g of ZrCl4 (9.9 mmol) in 40 mL of pentane (exothermic reaction, the mixture turns dark brown). The mixture was stirred at room temperature for two hours, then concentrated under reduced pressure to give a black powder, which was slurried in 50 mL of CH2Cl2, cooled to 0° C., and added of 9.9 mL of BCl3 1M in heptane (9.9 mmol). During the addition, the mixture turns from dark grey to dark green. This was allowed to warm to room temperature and stirred for 30 min at room temperature (complete conversion to the dichloride observed by 1H N at this time), then filtered and extracted with the same CH2Cl2 for 8 hours on a continuous extractor (the product precipitates in part as a yellow solid during extraction), the extract concentrated under reduced pressure to give a yellow powder, 3.74 g (96% yield based on Zr) of spectroscopically pure Ind2ZrCl2.
EXAMPLE 5
Synthesis of Ind2ZrCl2 
0.25 g of Ind2ZrMe2 (0.71 mmol) were dissolved in 10 mL of CH2Cl2 in a 25 mL Schlenk tube, and 0.71 mL of BCl3 1M in heptane (0.71 mmol) were added, a yellow precipitate start forming, and the slurry was stirred at room temperature for 1 hour, when 1H NMR showed the conversion to Ind2ZrCl2 to be quantitative. The yellow suspension was brought to dryness to give 0.27 g of yellow, powdery, analytically pure Ind2ZrCl2 (yield 97%). Its 1H NMR is identical to that of a true sample of Ind2ZrCl2.
EXAMPLE 6
Synthesis of Ind2ZrCl2 
0.172 g of Ind2ZrMe2 (0.49 mmol) were slurried in 5 mL of hexanes in a 10 mL Schlenk tube, and 0.49 mL of BCl3 1M in heptane (0.49 mmol) were added at room temperature, and the mixture stirred for 2 hours, to give a 45:55 mixture of Ind2ZrCl2 and Ind2ZrClMe (1H NMR), additional 0.3 mL of BCl3 1M in heptane (0.3 mmol) and sirred for additional 2 hours. At this point the reaction is complete and the product is analytically pure by 1H NMR.
EXAMPLE 7
Synthesis of Ind2ZrCl2 
300 mg of Ind2ZrMe2 (20790/21, 0.85 mmol) were dissolved in 20 mL of Et2O in a 50 mL Schlenk tube. 0.95 mL of a 2M solution of HCl in Et2O (Aldrich, 1.71 mmol) were added at room temperature. Gas evolution (CH4) is observed, together with instantaneous formation of a yellow precipitate. Removing the solvent under reduced pressure gives 320 mg of pure Ind2ZrCl2, yield 96%.
EXAMPLE 8
Synthesis of Ind2ZrMeCl
380 mg of Ind2ZrMe2 (20790/21, 1.08 mmol) were dissolved in 5 mL of CH2Cl2 in a 10 mL Schlenk tube. 175 mg of anhydrous FeCl3 (Aldrich, 99.9%, 1.08 mmol) were added at room temperature (immediate darkening to black), and then the mixture is heated at 40° C. for 6 hours. After 3 hours 1H NMR shows the presence of a 98:2 mixture of Ind2ZrClMe and residual Ind2ZrMe2 (yield of Ind2ZrMeCl 98%).
EXAMPLE 9
Synthesis of Ind2ZrI2 
164 mg of of Ind2ZrMe2 (0.46 mmol) were dissolved in 2 mL of CD2Cl2 in a 10 mL Schlenk tube. 120 mg of I2 crystals (0.47 mmol) were added at room temperature. The solution was warmed to 40° C. After 5 min stirring the I2 is fully solubilized, to give a bright orange solution that was stirred for 6 hours at 40° C. 1H-NMR analysis shows the presence of residual Ind2ZrMe2, and the two reaction products Ind2ZrIMe and Ind2ZrI2, in the ratio 6:67:27.
Additional 60 mg of I2 were added, and the solution stirred at room temperature for 72 hours.
1H-NMR analysis shows conversion to the target Ind2ZrI2.
Ind2ZrIMe: 1H-NMR (CD2Cl2, δ, ppm): −1.47 (s, 3H, Zr—CH3), 6.09 (t, 2H, Cp-H2, J=3.52 Hz), 6.39 (m, 2H, Cp-H(1,3)), 6.54 (m, 2H, Cp-H(3,1)), 7.23–7.28 (m, 2H, Ar), 7.64–7.69 (m, 2H, Ar).
Ind2ZrI2: 1H-NMR (CD2Cl2, δ, ppm): 2.19 (CH3I, cfr. CH3I in CDCl3=2.16 ppm); 6.42 (d, Cp-H(1,3), 4H, J=3.33), 6.64 (t, Cp-H(2), 2H, J=3.33), 7.30–7.40 (m, Ar, 4H), 7.66–7.75 (m, Ar, 4H.
EXAMPLE 10
Synthesis of Ind2TiClMe
Synthesis Ind2TiMe2 
31.0 mL of MeLi 1.6 M in Et2O (49.6 mmol) were added with stirring at room temperature to a solution of 3 g of indene (94% by G.C., 24.3 mmol) in 30 mL of diethyl ether over a period of about 10 minutes (exothermic reaction). The Schlenk tube was kept in a water bath to remove the heat of reaction. The reaction mixture was stirred for 30 minutes. After this time the solution turned from light yellow to orange. 1.34 mL of TiCl4 (99%, 12.2 mmol) were dissolved in 30 mL of pentane, and this solution was quickly added to the Li salt solution (exothermic reaction). The reaction mixture was stirred for two hours at room temperature with final formation of a dark brown suspension. The solvents were then removed under reduce pressure. The brown solid obtained was extracted in a Soxhlet apparatus with 80 mL of pentane. The filtrate was evaporated to dryness under reduced pressure to give 2.62 g of a yellow-brown powder (70% metal-based yield).
Anal. Calcd for C20H20Ti: C, 77.93; H, 6.54; Ti, 15.53. Found: C, 74.7; H, 6.35; Ti, 14.6; Cl, <0.05.
1H-NMR (C6D6, δ, ppm): −0.50 (s, Ti—CH3, 6H), 5.37 (t, Cp-H(2), 2H, J=3.24 Hz), 5.78 (d, Cp-H(1,3), 4H, J=3.24 Hz), 6.90–6.95 (m, Ar, 4H), 7.16–7.22 (m, Ar, 4H)
Synthesis Ind2TiClMe
0.43 g of Ind2TiMe2 (20790/77, 1.4 mmol) were dissolved in 15 mL of toluene in a 50 mL Schlenk. 0.32 mL of SiCl4 (99%, 2.79 mmol) were added at room temperature and the solution warmed up to 50° C. and stirred for 3 hours. 1H NMR reveals the formation of a 70:30 mixture of Ind2TiClMe and Ind2TiMe2. To bring the reaction to completion, another 2 molar equivalents of SiCl4 (0.32 mL) were added, and the red-orange solution stirred for 3 additional hours at 50 0C, then dried, to give a quantitative yield of Ind2TiClMe as a brick red powder.
1H-NMR (C6D6, δ, ppm): −0.08 (s, Ti—CH3, 3H), 5.52 (t, Cp-H(2), 2H, J=3.33 Hz), 5.80 (ddd, Cp-H(1 or 3), 2H, J=0.88, 1.96, 3.33 Hz), 5.86 (ddd, Cp-H(3 or 1), 2H, J=0.88, 1.96, 3.33 Hz), 6.85–7.31 (m, Ar, 8H).
COMPARATIVE EXAMPLE 11
Synthesis of Ind2ZrClMe
A slurry of 2.53 g of PbCl2 (Aldrich, MW=278.106, 9.10 mmol) in 15 mL of toluene was added to a solution of Ind2ZrMe2 (1.25 g, MW=351.594, 3.56 mmol) in 35 mL of toluene, in a 100 mL Schlenk flask. The dark orange suspension obtained was stirred 38 hours at room temperature and 10 hours at 40–45° C., during which time formation of a black powder was observed. The suspension was then filtered on 4 frit and the filtrate was evaporated to dryness under reduced pressure to give 1.1 g of a dark yellow powder, which was characterized by 1H NMR as a mixture of Ind2ZrMeCl and Ind2ZrCl2 in the ratio 90/10.
0.63 g of this mixture were treated with 30 mL of toluene and 1.2 g of PbCl2 (4.31 mmol). The suspension obtained was stirred for 30 hours at room temperature and 12 hours at 40° C. 1H NMR analysis showed decomposition of the product to indene. The yield of the reaction to give Ind2ZrClMe is 74%
COMPARATIVE EXAMPLE 12
0.67 g of CeCl3 (Aldrich, MW=246.48, 2.72 mmol) were added to a suspension of Ind2ZrMe2 (experiment 20826/5, 0.91 g, MW=351.594, 2.59 mmol) in 30 mL of toluene, in a 100 mL Schlenk flask. The light brown suspension obtained was stirred 24 hours at room temperature, but no reaction was observed by 1H NMR analysis. It was then treated with additional 0.64 g of CeCl3 (2.6 mmol) and stirred 3 hours at room temperature and 4 hours at 40° C. No reaction was observed by 1H NMR.
EXAMPLE 13
Synthesis of Ind2ZrCl2 
A solution of SCl2 (Riedel de Haen, 0.16 g, MW=102.966, 1.55 mmol) in 10 mL of CH2Cl2 was added to a brown suspension of Ind2ZrMe2 (experiment 20826/7-9, 0.55 g, MW=351.594, 1.56 mmol) in 10 mL of CH2Cl2. During the addition exothermicity was observed and the reaction mixture turned clearer. After 3 hours stirring at room temperature the reaction mixture turned reddish and 1H NMR analysis showed a mixture of Ind2ZrCl2 and Ind2ZrMeCl in the ratio 61/39. Additional 0.055 g of SCl2 (0.53 mmol) were added to the reaction mixture. After 1 hour stirring the brown suspension obtained was evaporated to dryness under reduced pressure to give 0.61 g (100% metal-based yield) of a clear brown powder, which 1H NMR analysis showed to be Ind2ZrCl2 with some impurities.
EXAMPLE 14
Synthesis of Ind2ZrI2 
Crystals of I2 (0.70 g, MW=253.809, 2.76 mmol) were added to a suspension of Ind2ZrMe2 (experiment 20826/7-9, 0.48 g, MW=351.594, 1.36 mmol) in 20 mL of CH2Cl2. The orange suspension turned to dark purple in few minutes. After 30 minutes stirring at room temperature, the suspension was evaporated to dryness under reduced pressure to give 0.83 g (100% yield) of an orange powder, which was characterized by 1H NMR as pure Ind2ZrI2.
1H-NMR (CD2Cl2, δ, ppm): 6.42 (d, 4H, Cp-H(1,3), J=3.33 Hz); 6.64 (t, 2H, Cp-H(2), J=3.33 Hz); 7.30–7.40 (m, 4H, Ar); 7.66–7.75 (m, 4H, Ar).
EXAMPLE 15
Synthesis of Ind2ZrBr2 
A solution of 0.52 g of Br2 (Fluka, 3.69 mmol) in 7 ml of CH2Cl2 was added to a solution of 0.65 g of Ind2ZrMe2 (1.85 mmol) in 20 ml of CH2Cl2. The reaction was exothermic. The brown suspension obtained was stirred at room temperature for 18 hours and then evaporated to dryness under reduced pressure to give a reddish powder. This powder showed the presence of some impurity, so it was treated with ether and filtered. The residue was still not clean enough, so it was treated with toluene and filtered. The filtrate was evaporated to dryness under reduced pressure to give pure Ind2ZrBr2 which was characterized by 1H NMR.
1H NMR (CD2Cl2, δ, ppm): 6.28 (d, 4H, Cp-H(1,3), J=3.42 Hz); 6.57 (t, 2H, Cp-H(2), J=3.42 Hz); 7.30–7.38 (m, 4H, Ar); 7.63–7.70 (m, 4H, Ar).
EXAMPLE 16
Synthesis of Me2Si(Me4Cp)(t-BuN)TiClMe
0.69 mL of SiCl4 (5.98 mmoles) previously diluted in 2 mL of CH2Cl2 were added dropwise at romm temperature to a solution of 0.98 g of Me2Si(Me4 Cp)(t-BuN)TiMe2 (obtained according to WO 00/75151) in 5 mL of CH2Cl2. After 6 h, the monochloro complex was obtained in nearly 100% yield.
EXAMPLE 17
Synthesis of (N-ethyl-5,6-dihydroindeno[2,1-b]indol-6-yl)(t-BuN)TiCl2 
0.71 g of CuCl (6.85 mmoles) were added at room temperature to a solution of 0.6 g (1.37 mmoles) of dimethylsilyl(tert-butylamino)(N-ethyl-5,6-dihydroindeno[2,1-b]indol-6-yl)dimethyl titanium (obtained according to WO 01/53360) in 5 mL of CH2Cl2. The mixture of reaction was monitored by 1H-NMR after 1 h, 4 h and one night of stirring. The suspension was filtered and the filtrate was dried in vacuo obtaining a red-brown sticky solid (yield 100%). 1H-NMR shows the formation of dimethylsilyl(tert-butylamino)(N-ethyl-5,6-diydroindeno[2,1-b]indol-6-yl)dichloro titanium.
EXAMPLE 18
Synthesis of (N-ethyl-5,6-dihydroindeno[2,1-b]indol-6-yl)(t-BuN)TiCl2 
0.7 mL (0.7 mmoles) of BCl3 1.0 M in heptane were added at 0° C. to a solution of 0.306 g (0.7 mmoles) of dimethylsilyl(tert-butylamino)(N-ethyl-5,6-dihydroindeno[2,1-b]indol-6-yl)dimethyl titanium (obtained according to WO 01/53360) in 8 mL of Et2O, after 2 hours of stirring at room temperature the 1H-NMR analysis shows the formation of the dichloro complex. The solvent was dried in vacuo and the crude was washed with 7 mL of toluene, the residue was dried under reduced pressure, obtaining a red brown solid, which resulted almost pure desired product by 1H-NMR (yield 100%).
1H-NMR (C6D6, δ, ppm): 0.61 (s, 3H, Si—CH3); 0.75 (s, 3H, Si—CH3); 1.15 (t, 3H, CH3, J=7.24 Hz); 1.28 (s, 9H, t-Bu); 3.81 (q, 2H, CH2, J=7.24 Hz); 6.98–7.92 (m, 8H, Ar).
1H-NMR (CDCl3, δ, ppm): 1.01 (s, 3H, Si—CH3); 1.10 (s, 3H, Si—CH3); 1.36 (s, 9H, t-Bu); 1.54 (t, 3H, CH3, J=7.24 Hz); 4.38 (q, 2H, CH2, J=7.24 Hz), 7.21–8.05 (m, 8H, Ar).

## Claims

1. A process for preparing dihalide or monohalide metallocene compounds of formula (I),


(Cp)(ZR1m)n(A)rMLqL′s  (I)


wherein (ZR1m)n is a divalent group bridging Cp and A; Z being C, Si, Ge, N or P, and the R1 groups, equal to or different from each other, being hydrogen or linear or branched, saturated or unsaturated C1–C20 alkyl, C3–C20 cycloalkyl, C6–C20 aryl, C7–C20 alkylaryl or C7–C20 arylalkyl groups, optionally containing one or more heteroatoms belonging to groups 13–17 of the Periodic Table of the Elements or two R1 can form a aliphatic or aromatic C4–C7 ring that can bear substituents;
Cp is a substituted or unsubstituted cyclopentadienyl group, optionally condensed to one or more substituted or unsubstituted, saturated, unsaturated or aromatic rings, containing from 4 to 6 carbon atoms, optionally containing one or more heteroatoms belonging to groups 13–17 of the Periodic Table of the Elements;
A is O, S, NR2, PR2, wherein R2 is hydrogen, a linear or branched, saturated or unsaturated C1–C20 alkyl, C3–C20 cycloalkyl, C6–C20 aryl, C7–C20 alkylaryl or C7–C20 arylalkyl, or a substituted or unsubstituted cyclopentadienyl group, optionally condensed to one or more substituted or unsubstituted, saturated, unsaturated or aromatic rings, containing from 4 to 6 carbon atoms, optionally containing one or more heteroatoms belonging to groups 13–17 of the Periodic Table of the Elements;
M is selected from zirconium, titanium or hafnium;
L, equal to or different from each other, are selected from the group consisting of chlorine, bromine, and iodine;
L′ is selected from the group consisting of hydrogen, a linear or branched, saturated or unsaturated C1–C20 alkyl, C3–C20 cycloalkyl, C6–C20 aryl, C7–C20 alkylaryl and C7–C20 arylalkyl group, optionally containing at least one Si or Ge atoms;
m is 1 when Z is N or P, and m is 2 when Z is C, Si or Ge;
n is 0, 1, 2, 3 or 4, being 0 when r is 0 or 2;
r is 0, 1 or 2;
q is 1, 2, or 3;
s is 0 or 1; wherein q+s=3−r;
said process comprising contacting a compound of formula (II)


(Cp)(ZR1m)n(A)rML′y  (II)



wherein
y is equal to s+q;
with an halogenating agent selected from the group consisting of T1Lw1, T2Lw2, O=T3Lw3, and R6C(O)L, mercury dichloride (HgCl2) being excluded, wherein T1 is a metal of groups 3–13 of the Periodic Table of Elements or of the lanthanides series;
T2 is a nonmetal element of groups 13–16 of the Periodic Table of Elements with the exclusion of carbon;
T3 is selected from the group consisting of C, P and S;
O is an oxygen atom bonded to T3 through a double bond;
R6 is selected from a linear or branched, saturated or unsaturated C1–C20 alkyl, C3–C20 cycloalkyl, C6–C20 aryl, C7–C20 alkylaryl or C7–C20 arylalkyl;
H is hydrogen;
w1 is equal to the oxidation state of the metal T1;
w2 is equal to the oxidation state of the element T2;
w3 is equal to the oxidation state of the element T3 minus 2.

2. The process according to claim 1, wherein divalent bridge (ZR1m)n is selected from the group consisting of CR12, (CR12)2, (CR12)3, SiR12, GeR12, NR1 and PR1;
Cp, which is π-bonded to said metal M, is selected from the group consisting of cyclopentadienyl, mono-, di-, tri- and tetra-methyl cyclopentadienyl; 4-tertbutyl-cyclopentadienyl; 4-adamantyl-cyclopentadienyl; indenyl; mono-, di-, tri- and tetra-methyl indenyl; 4,5,6,7-tetrahydroindenyl; fluorenyl; 5,10-dihydroindeno[1,2-b]indol-10-yl; N-methyl- or N-phenyl-5,10-dihydroindeno [1,2-b]indol-10-yl; 5,6-dihydroindeno[2,1-b]indol-6-yl; N-methyl- or N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl; azapentalene-4-yl; thiapentalene-4-yl; azapentalene-6-yl; thiapentalene-6-yl; mono-, di- and tri-methyl-azapentalene-4-yl and 2,5-dimethyl-cyclopenta[1,2-b:4,3-b′]-dithiophene; and
A is cyclopentadienyl, mono-, di-, tri- and tetra-methyl cyclopentadienyl; 4-tertbutyl-cyclopentadienyl; 4-adamantyl-cyclopentadienyl; indenyl; mono-, di-, tri- and tetra-methyl indenyl; 4,5,6,7-tetrahydroindenyl; fluorenyl; 5,10-dihydroindeno[1,2-b]indol-10-yl; N-methyl- or N-phenyl-5,10-dihydroindeno [1,2-b]indol-10-yl; 5,6-dihydroindeno[2,1-b]indol-6-yl; N-methyl- or N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl; azapentalene-4-yl; thiapentalene-4-yl; azapentalene-6-yl; thiapentalene-6-yl; mono-, di- and tri-methyl-azapentalene-4-yl; 2,5-dimethyl-cyclopenta[1,2-b:4,3-b′]-dithiophene; N-methyl; N-ethyl; N-isopropyl; N-butyl; N-phenyl; N-benzyl; N-cyclohexyl; or N-cyclododecyl.

3. The process according to claim 2, wherein the divalent bridge (ZR1m)n is selected from the group consisting of Si(CH3)2, SiPh2, CH2, (CH2)2, (CH2)3 and C(CH3)2.

4. The process according to claim 1, wherein the halogenating agent is selected from the group consisting of FeCl3, CuCl2, ZnCl2, BCl3, BBr3, SiCl4, PCl5, SOCl2, POCl3, CH3C(O)Cl, C6H5CH2C(O)Cl, C6H5C(O)Cl, CH3CH2CH2C(O)Cl, Br2, Cl2, HBr and HI.

5. The process according to claim 1, wherein the process is carried out in an aprotic polar or apolar solvent.