bluuebunny/crossref_metadata_2025 huggingface dataset:
Dilatometer Studies of the Apparent Molar Volume Limiting Law for High-Charge Electrolytes
Authors: Bottomley GA , Glossop LG , Staunton WP
Published: September 2010

A continuous-dilution
dilatometer, of the tilting type, specifically designed for study of the
apparent molar volumes of aqueous electrolytes at low concentrations, is
described. Results at 298.16 K have been secured for multivalent (� 3, � 4, �
6) univalent electrolytes which demonstrate that the apparent molar volumes
vary with c� in approximate conformity with the Debye-Huckel
limiting-law slopes. Data are presented for: [Co(en)3] Cl3,
K3 [CO(CN)6], [Pt(en)3] Cl4, K4
[Mo(CN)8], [C0{(0H)2Co(en)2}3]
(NO3)6,Na6C6(C00)6, K4
[Fe(CN)6] and [Co(en)3] (C1O4)3 Ion
pairing is a significant disturbing factor which hinders treatment of the data
in terms of extended forms of the Debye-Huckel equation.
A Proton Magnetic Resonance Study of Ligand Exchange on the Hexakis-(N, N-dimethylformamide)magnesium(II) Ion
Authors: Pisaniello DL , Lincoln SF
Published: September 2010

The rate of ligand exchange
on the hexakis(N,
N-dimethylformamide) magnesium(II) ion, [Mg(dmf)6]2+, in CD2Cl2
and (CD3)2CO diluents is found to be virtually
independent of the concentration of free dmf. This is
consistent with a reaction mechanism in which bond rupture is the major factor
in the rate-determining step for the exchange process. For a solution in which
[Mg(dmf)62+],[dmf] and [CD2Cl,] are 0.0768, 0.397
and 13.9 mol dm-3 respectively, kex(215
K) = 23.5 � 3.2 s-1, ΔH‡ = 77.8 + 3.0 kJ mol-1 and ΔS‡
= l46 � 14 J K-1 mol-1, and similar kinetic parameters
characterize other CD2Cl2 solutions. In (CD3)2CO
diluent the ligand-exchange process is characterized by smaller ΔH‡ and ΔS‡
values. These data are discussed in conjunction with kinetic data reported for
other magnesium(II) systems.
Single-Frequency Proton Decoupling in 13C N.M.R. Spectra. 13C Chemical Shifts and Methyl Substituent Chemical Shifts in Methylquinolines
Authors: Johns SR , Willing RI , Claret PA , Osborne AG
Published: September 2010

Single-frequency decoupled
and fully coupled spectra have been used to assign 13C chemical
shifts to a number of methyl-substituted quinolines,
and the merits of the various decoupling techniques are compared. Ambiguities
in assignments of closely similar chemical shifts by the substituent chemical
shift (scs) method have been resolved by meta-13C-1H
coupling constants. Long-range methyl scs parameters
in methylquinolines, and the limitations of the scs method in shift assignments, are discussed.
Acetylenic Acids. IV. The Reactions of Alkoxy-Substituted Phenylpropiolic Acids and Esters with Sulfur Halides, Particularly Thionyl Chloride
Authors: Bonnin CM , Cadby PA , Freeman CG , Ward AD
Published: September 2010

3,4-Dialkoxy-substituted phenylpropiolic acids and esters react with thionyl chloride to give good yields of substituted
1-benzothiophen systems. Similar reactions of m-and p-methoxyphenylpropiolic acids and
3,4,5-trimethoxyphenylpropiolic acid, which yield mixtures of products, are
reported. In contrast, 2,5- and 2,3-dimethoxyphenylpropiolic acids gave
mixtures in which a coumarin is the major product.
The effect of adding pyridine to the reaction mixture is outlined. Reactions
involving sulfur monochloride and sulfur dichloride
generally gave much lower yields of these products. Attempts to form organometallic intermediates from the
3-chloro-1-benzothiophen products were unsuccessful.
Cobalt (II) and Nickel(II) Complexes with Sterically Hindered Heterocyclic Ligands and Oxalate, Malonate and Succinate Ions Acting as Symmetric Quadridentate Bridging Ligands
Authors: Preti C , Tosi G
Published: September 2010

Mixed complexes of
cobalt(II) and nickel(II) ions with tetrahydro-1,4-thiazin-3-one (tht), thiazolidine- 2-thione (ttz) and benzoxazole-2(3H)-thione (bot), and aliphatic dicarboxylic acids, such as oxalic, malonic
and succinic, are described. The newly prepared
compounds are characterized on the basis of near-infrared and far-infrared
spectroscopy and electronic spectra, as well as by magnetochemical
investigations. All physical measurements agree with a polymeric linear-chain
structure of the complexes in which the oxalate, malonate
or succinate dianion acts as a tetradentate
bridging ligand linking two metal ions. The metal ions attain six-coordination
through the four oxygens of the anion and the donor atoms of two hetero ligands
acting always as monodentate oxygen donors in the
case of tht and monodentate
nitrogen donors in the case of ttz and bot. The complexes having a 1 : 1 metal/ligand molar ratio
achieve an octahedral structure through the coordination of a water molecule.
Spectroscopic parameters for the cobalt and nickel complexes are compared with
similar chromophores containing sulfur, oxygen and
nitrogen donor atoms; the Dq values are in keeping
with the infrared results and with literature data for MO6, MN2O4
and NiNO5 chromophores.
Reactions of Trifluoromethyl Radicals. IV. Hydrogen Abstraction from Dichlorosilane and Trichlorosilane
Authors: Arthur NL , Christie JR , Mitchell GD
Published: September 2010

The hydrogen abstraction
reactions of SiH2Cl2 and SiHCl2 with CF3
radicals
CF3+SiH2Cl2 → CF3H + SiHCl2
CF3+SiH2Cl3 → CF3H +
SiHCl3
have been studied in the
temperature ranges 65-227�and 64-294�, respectively. The rate constants, based
on the value of 1013.36 cm3 mol-1 s-1 for the
recombination of CF3 radicals, are given by (k in cm3 mol-1 s-1, E in J mol-1):
logk1 = (12.08 �
0.04)-(25600 � 280)/19.145T
logk2 = (11.92 �
0.02)-(27020 � 160)/19.145T
The Structure and Function of Oestrogens. I. Synthesis of 4b-Methyl-trans-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol
Authors: Collins DJ , Matthews WA
Published: September 2010

Oxidation of
2,8-dimethoxy-5,6,11,12-tetrahydrochrysene (17) with m-chloroperbenzoic acid gave
2,8-dimethoxy-4b,5,6,10b,ll,l2-hexahydro-4b,10b-epoxychrysene (20). Treatment
of this with methylmagnesium bromide afforded an
inseparable mixture of 2,8-dimethoxy-4b-methyl-4b,5,6,12- tetrahydrochrysene
(28) and 2,8-dimethoxy-5,6-dihydrochrysene (18) in the ratio 7 : 3.
Hydrogenation of this mixture over 10% palladium-charcoal gave
2,8-dimethoxy-4b-methyl-trans-4b,5,6,10b,11,12-
hexahydrochrysene (30) which was readily separable
from (18). Demethylation of compound (30) yielded
4b-methyl-trans-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol
(11a), which was required for assay as an oestrogen.
Viscosity and Transference Number Measurements of Concentrated Nickel Chloride Solutions at 298.15 K
Authors: Phang S
Published: September 2010

The viscosity and
transference numbers of the nickel ion constituent in nickel chloride solutions
are reported between about 0.1 and 4.3 mol
dm-3. The e.m.f. method was used to
measure the transference number. The latter was compared with values from other
methods. The viscosity results were used to test the Wishaw-Stokes equation.
Charge Separation in Transition States of Reactions Involving Neutral Molecules as Reactants
Authors: Poh B
Published: September 2010

It is shown that the
parameter m in the Grunwald-Winstein equation, log(k/k0) = mY, can be equated to z/z0
where z0 is the charge
separation in the transition state of solvolysis of t-butyl chloride in a given
pair of solvents and z is the charge separation in the transition state of a
reaction in which only neutral molecules are involved as reactants in the same
pair of solvents.
Molybdenum and Tungsten Nitrosyl Complexes with Dithiocarbamate Ligands
Authors: Broomhead JA , Budge JR
Published: September 2010

Molybdenum and tungsten nitrosyl complexes with dithiocarbamato
ligands have been prepared and characterized by analysis, and 1H
n.m.r, and infrared studies. The molybdenum complexes are formulated as
seven-coordinate species [Mo(NCO)L(S2CNEt2)2NO]-
(L = Cl-, N3-,
NCS-),{Mo(NCO)(S2CNEt2)2NO}2N2H4
and [Mo(NCO)B(S2CNEt2)2NO](B = NH3,
pyridine). Likely stereochemistries are discussed.
New tungsten complexes have been prepared by photochemical reactions of cis-[W(S2CNEt2)2(NO)2]
to give [WL2(S2CNEt2)2NO]-,
[WL(S2CNEt2)2(Me2SO)NO](L = NCO-,
N3-, NCS-) and [W(NCO)(S2CNEt2)2(MeCONMe2)NO].
Assignments for the nitrosyl infrared bands in cis-[MO(S2CNEt2)2(NO)2]
and [Mo(NCO)(S,CNEt2)2(Me2SO)NO]
havebeen made by using 15NO
labelled ligands.
Chemistry of the Group 1B Metals. XI. Further Studies of Some Poly(pyrazolyl)-borate Complexes of Copper(I)
Authors: Abu Salah OM , Bruce MI , Walsh JD
Published: September 2010

A series of 21 poly(pyrazolyl)borate complexes of copper(I) have been prepared
either (i) from reactions between the appropriate
carbonyl derivatives, Cu(CO)[(pz)3BR](R =
H or pz) or Cu(CO)[(Me2pz)3-BH],
and donor ligands, L, or (ii) from reactions between copper(I) chloride, L, and
the appropriate poly(pyrazolyl)borate anion [H2B(pz)2-,ph2B(pz)3-,
HB(pz)3-, HB(Me2pz)3-
or B(pz)4-]. Complexes containing L = CO,
PEt3, P(C6H4Me)3 (C6H4Me
= o-, m- or p-tolyl), As(C6H4Me-p)3,P(OMe)3, P(OMe)3 (OPh)3,
dppm, dppe, diars, MeC(CH2PPh2)3
or ButNC are described. Most contain four-coordinate
copper(I), although the bis(pyrazolyl)borate complexes are formally
three-coordinate.
Hydroboration-Oxidation of Benzocycloalkenes
Authors: Marshall PA , Prager RH
Published: September 2010

The products of the
hydroboration-oxidation of the benzocycloalkenes (1 ; n = 1-5) with diborane
and thexylborane have been studied. With indene, diborane yields 86% of
indan-2-ol and thexylborane yields 99%. Each of the other benzocycloalkenes
gives approximately 90% of the α-alcohol with diborane, and increasing
amounts (10-38%) of the β-alcohol with thexylborane. Electronic factors
are suggested to be paramount to explain the difference between indene and the
other alkenes. A number of rearrangement reactions have been encountered during
the synthesis of the alkenes.
Temperature-Dependent Isotropic Shifts in Some Paramagnetic Transition Metal Acetylacetonates
Authors: Gregson AK , Doddrell DM , Bendall MR
Published: September 2010

A detailed analysis of the
temperature dependence of the CH3 and CH isotropic shifts in V(acac)3 (Hacac =
pentane-2,4-dione) and the CH3 isotropic shift in Ru(acac)3 is given.
The temperature dependence of the CH3 isotropic shifts in Mn(acac)3 and Fe(acac)3
are also reported. The pseudo-contact shifts are negligible for them all except
in Ru(acac)3.
The contact shifts cannot be explained with a single value of the Fermi
coupling constant and it is suggested that either vibrational effects or Fermi
contact contributions from excited states are responsible.
Circular Dichroism Spectra of Cobalt(III), Platinum(II) and Molybdenum(0) Complexes of 1-Phenylethane-1,2-diamine
Authors: Hawkins CJ , McEniery ML
Published: September 2010

The circular dichroism
spectra are presented for the complexes, trans-[CoL2C12]+,
trans-[CoL2Br2]+,
[CoL(NH3)4]3+, [CoL(CN)4]-,
[MoL(CO)4] and [PtL(py)2]2+, where L is
(R)-1-phenylethane-l,2- diamine, in a number of solvents. The solvent
dependence of the spectra for the cobalt(m) complexes has been analysed in
terms of stereoselective solvation of the diamine N-H protons. The spectra are
compared with those of the analogous (R)-propane-1,2-diamine complexes. This
comparison shows that the so-called 'conformational effect' is not predominant.
The Chemistry of Aryllead(IV) Tricarboxylates. Reaction with Aromatics to Give Biaryls
Authors: Bell HC , Kalman JR , May GL , Pinhey JT , Sternhell S
Published: September 2010

Aryllead(IV) tricarboxylates
have been shown to react in trifluoroacetic acid with a range of aromatics to
give biaryls. With aromatics more reactive than toluene the yields are
generally good and the method provides a useful synthesis of unsymmetrical biaryls.
A study of the mechanism of the reaction indicates an electrophilic
substitution, although at least with the more reactive substrates this does not
involve a free aryl cation. It is suggested that, for these compounds, the
formation of a π-complex in which the aryl-lead bond is still intact is rate
determining. For benzene and toluene, which give low yields in the above
reaction, a marked improvement in the yield of the biaryl can be achieved by
using AlCl3 in place of trifluoroacetic acid. Al(OCOCF3)3,
Al(OCOCF2CF3)3 and Al(OCOCF2CF2CF3)3
have been shown to be equally effective in promoting the reaction, and, unlike
AlCl3, do not suffer the disadvantage of causing alkyl and/or aryl
group migrations.
Chemistry of the Group 1B Elements. XII. Some Poly(pyrazolyl)borate Complexes of Silver
Authors: Salah OMA , Ashby GS , Bruce MI , Pederzolli EA , Walsh JD
Published: September 2010

Reactions between silver(1)
salts and poly(pyrazolyl)borate anions in the
presence of donor ligands have given 21 complexes of general formula AgL(RnBH4-n) [L = PPh3, P(c6H4Me)3,
P(OMe)3, P(OPh)3, AsPh3,
SbPh3, o - C6H4(
AsMe2)2 or ButNC; RnBH4-n
= HB(pz)3, HB(Me2pz)3 orB(pz)4], and [Ag(HBR3)]2(dppe)
(R = PZ or Me2pz) and {[Ag(HBR3)](dppm)}n (R =
PZ, n = 1 ; R = Me2pz, n = 2). Their possible structures are
discussed in the light of various spectroscopicdata obtained for them.
The Kinetics and Mechanism of a Reaction in Which Ligand Substitution is Accompanied by a Spin-State Change: Observation of the Elusive Monodithiocarbamatonickel(II) Complex in Dimethyl Sulfoxide
Authors: Nichols PJ , Grant MW
Published: September 2010

In solutions in Me2SO containing low concentrations of diethyldithiocarbamate ion (dtc-) and very
high concentrations of Ni(Me2SO)62+ ion, the hitherto undetected Ni(dtc)+ complex is kinetically
stabilized and its electronic spectrum can be recorded. The mono complex is thermodynamically
unstable and is converted into Ni(dtc)2 by two independent pathways, one involving direct reaction
between Ni(dtc)+ and dtc-, the other being a dimerization reaction, 2Ni(dtc)+ → Ni2+ + Ni(dtc)2.
Analysis of the mechanistic scheme
Ni2+ + dtc ↔ Ni(dtc)2
Ni(dtc)+ + dtc- → Ni(dtc)2
2Ni(dtc)+ → Ni2+ + Ni(dtc)2
gives k1 = 3 × 103 l, mol-1 s-1, k-1 ≈ 0.01 s-1, k2 ≈ 4 × 105 l, mol-1 s-1 and k3 ≈ 1 × 103 l. mol-1
s-1. Coordinated dtc- exerts a significant labilizing effect on coordinated Me2SO molecules in
Ni(dtc)+.
Steric Effects in Forward and Reverse Menschutkin Reactions of Some Pyridines, Quinolines and Thiazoles
Authors: Deady LW , Finlayson WL , Korytsky OL
Published: September 2010

The effects of ortho alkyl substituents on the rates of
methylation of pyridine and demethylation of N-methylpyridinium iodides are compared (some quinolines are
included as 'substituted pyridines'). For monosubstituted compounds,
substituent steric effects are twice as important in the methylation (forward)
reaction as in the demethylation reaction. In contrast, the ratio is 3 : 1 for
disubstituted compounds, because the substituent effects are additive in the
reverse reaction but greater than additive in the forward reaction. Some
thiazole results are also reported and, here, steric effects on the forward
reaction are small while no steric acceleration of the reverse reaction is
evident.
Nitrones and Oxaziridines. XXIV. Preparation and Reactions of 3-Bromo-2-cyano-1-pyrroline 1-Oxides: Formation of 2-Cyano-3-oxo-1-pyrroline 1-Oxides and 5-Cyano-2H-pyrrole 1-Oxides
Authors: Black DSC , Blackman NA , Brown RFC
Published: September 2010

2-Cyano-1-pyrroline
1-oxides (1) have been brominated using N-bromosuccinimide
and the resulting 3-bromo-2-cyano-1-pyrroline I-oxides (2) have been further
transformed into (i) 2-cyano-1-pyrrolin- 3-yl nitrate 1-oxides (3) by treatment
with silver nitrate, (ii) 2-cyano-3-hydroxy-1-pyrroline 1-oxides (4) by
treatment with sodium bicarbonate, and (iii) 5-cyano-2H-pyrrole 1-oxides (8) by
treatment with either pyridine N-oxide
or triethylamine. The 2-cyano-3-oxo-1-pyrroline 1-oxides (5) were prepared by
reaction of the nitrate esters (3) with triethylamine.
Molecular Orbital Studies of Enzyme Catalysed Reactions. Rearrangement of Chorismate to Prephenate
Authors: Andrews PR , Haddon RC
Published: September 2010

Molecular orbital calculations are used to describe the reaction surface for the non-enzymic Claisen
rearrangement of chorismate to prephenate, which may proceed through either a boat-like or a
chair-like transition state. Detailed molecular geometries are obtained for the neutral and dianionic
forms of chorismate, prephenate, and the alternative transition states. The transition states are
asymmetric structures in which the breaking C-O bond (c. 1.45 A) is significantly shorter than the
making C-C bond (c. 1.95 A). The alternative reaction pathways have almost identical enthalpies
of activation (chair, 277.4 kJ/mol ; boat, 282.8 kJ/mol; dianionic forms) which result partly
from a loss of internal bond strength and partly from repulsive interactions between the polar
carboxyl groups. Protonation stabilizes the transition states (chair, 247.3 kJ/mol; boat, 248.5 kJ/mol ;
diacid forms) by delocalization of charge in the carboxyl groups, and a similar mechanism is proposed
for the greatly reduced enthalpy of activation in aqueous solution (86.6 kJ/mol). The enthalpy
difference between the alternative reaction pathways is insufficient to define a preferred transition
state structure, and either pathway may be favoured for the non-enzymic reaction in aqueous
solution. For the enzyme-catalysed reaction the chair pathway is used, and the calculated transition
state structures and enthalpy barriers provide information relevant to the catalytic mechanism. They
indicate that an active site comprising only two essential binding groups is sufficient to account
for catalysis; the orientation of these groups within the active site should allow simultaneous bond
formation, accompanied by charge delocalization, to both carboxyl groups of the transition state,
but not to those of substrate or product. The calculated structure for the chair transition state,
taken in conjunction with those for chorismate and prephenate, thus provides a template for the
active sites of chorismate mutases.
Reaction of 2-Nitropropan-2-ide Ion with m-Nitrobenzylidene Dibromide and Dichloride
Authors: Norris RK , Smyth-King RJ
Published: September 2010

The reactions of m-nitrobenzylidene dichloride and
dibromide with lithium 2-nitropropan-2-ide in dimethyl sulfoxide give a complex
mixture of products (unlike the p-nitro
isomers), which include: 1-chloro(bromo)-2-methyl-2-nitro-1-m-nitrophenylpropane and β,β-dimethyl-m-nitrostyrene, formed by SRN1
and ERC1 processes; 1-(1-methyl-1-nitroethyl)-2(and
4)-(2-methylprop-1-enyl)-4(and 2)- nitrobenzene, formed by nucleophilic ring
attack; and acetone O-m-nitrobenzoyloxime and m-nitrobenzoic acid formed by radical
and/or ionic processes. Several routes to 2-methyl-2-nitro-1-m-nitrophenylpropan-1-one, proposed as
an intermediate leading to the above oxime ester, are proposed. Inhibitory and
catalytic effects on these reactions are discussed.
Mass Spectrometric Studies. XIII. Spirocyclic Glycidic Esters
Authors: Baldas J , Iakovidis D , Porter QN
Published: September 2010

The mass spectra of a
series of spirocyclic glycidic esters derived from cyclo-butanones,
-pentanones, -hexanones, -heptanones and -octanones show the following
characteristic fragmentations: (i) a rearrangement involving migration of the
ester alkoxy group to the ring junction, followed by elision of the group COCR=O
(R = H or Me), and (ii) loss of the alkoxycarbonyl group by α-fission,
followed by ring-contraction and loss of the elements of acetaldehyde. The
major fragmentations are supported by deuterium-labelling experiments, and a
number of minor decompositions are described.
Complexes of Carbohydrates with Metal Cations. XI. Paper Electrophoresis of Polyols in Solutions of Calcium Ions
Authors: Angyal SJ , Mills JA
Published: September 2010

Paper electrophoresis in an
electrolyte containing calcium ions is a method suitable for the separation and
characterization of many polyhydroxy compounds. The method is based on the
formation ofcomplexes between the cation
and at least two hydroxyl groups of the compounds. Electrophoretic mobilities
are listed for many sugars, methyl glycosides and cyclitols. The mobilities
convey someinformation on the
structure of the compounds. The correlation of electrophoretic mobilities with
the configuration and conformation of the compounds is discussed.
The Structure of Eremoacetal, a Sesquiterpene From Eremophila rotundifolia
Authors: Dimitriadis E , Massy-Westropp R
Published: September 2010

Eremoacetal, a
sesquiterpene acetal isolated from Eremophila
rotundifolia, has been shown to be (+)-(1R,3S,5R)-1-(furan-3'-yl)-5-methyl-3-(2'-methylprop-1'-enyl)-2,8-dioxabicyclo[3,2,1]octane
(1).
Nitrones and Oxaziridines. XXVI. Reaction of Grignard Reagents with 3-Oxo-1-pyrroline 1-Oxides and Synthesis of 2H-Pyrrole 1-Oxides
Authors: Black DSC , Blackman NA , Johnstone LM
Published: September 2010

Alkyl-, benzyl-, allyl- and
vinyl-magnesium halides undergo selective addition to the carbonyl group of
2-phenyl- and 2-t-butyl-3-oxo-1-pyrroline 1-oxides (1a,b) to afford a range of
alcohols. These can be dehydrated easily to form 2H-pyrrole 1-oxides (3) or 3-alkylene- or
3-arylmethylene-1-pyrroline 1-oxides (4) depending on the precise structural
features involved in each case. Phenylmagnesium bromide underwent addition only
to the oxo nitrone (la) and failed to react with (1b).
1,3-Dimethyl-2-oxabicyclo[2,2,2]-octane-3-methanol and 1,3-Dimethyl-2-oxa-bicyclo[2,2,2]octane-3-carboxylic Acid, Urinary Metabolites of 1,8-Cineole
Authors: Flynn TM , Southwell IA
Published: September 2010

Examination of urinary
metabolites from brushtail possums (Trichosurus
νulpecula) maintained on a diet of fruit
impregnated with 1,8-cineole (1) yielded two new compounds shown by spectral
analysis, synthesis and interconversion to be
1,3-dimethyl-2-oxabicyclo[2,2,2]octane-3-methanol (2) (9-hydroxycineole) and
1,3-dimethyl-2-oxabicyclo[2,2,2]octane-3-carboxyic acid (3) (cineol-9-oic
acid).
Electron-Transfer Reactions in Non-Aqueous Media. V. Solvent Effects in the Reduction of CoN3(NH3)52+ by Iron(II)
Authors: Westcott TJ , Watts DW
Published: September 2010

The reduction of CoN3(NH3)52+
by iron(II) is rate-determined by a two-stage process involving the reversible
formation of an azide-bridged precursor complex prior to electron transfer in
each of the solvents water, Me2SO, aqueous Me2SO and
HCONMe2. The activation parameters in H2O and Me2SO,
and the trends shown with increasing Me2SO concentrations in aqueous
Me2SO, are similar to the properties of the previously studied CoCl(NH3)52+
and CoBr(NH3)52+ systems and contrast with the reduction
of COF(NH3)52+. The results are consistent
with a bridged precursor complex octahedral at both the iron and cobalt atoms
in water but with tetrahedral coordination about the iron in Me2SO.
In HCONMe2, as in the reduction of COF(NH3)52+,
COCl(NH3)52+ and COBr(NH3)52+,
the precursor complex is a significant part of the reacting solutions, and as a
result the experimental pseudo-first-order rate constants for the loss of CoIII
are not linearly dependent on the concentration of FeII. The initial
spectra of the reacting solutions in this system also indicate significant
concentrations of the precursor complex.
Reactions of Alkynes with Dicarbonyl(η-cyclopentadienyl)iridium
Authors: Corrigan PA , Dickson RS
Published: September 2010

Six organometallic
complexes have been isolated from the reaction between (η-C5H5)Ir(C0)2 and hexafluorobut-2-yne
at 120-160�. Both the cis and trans
isomers of the σ-bridging alkyne complex (η C5H5)2Ir2(CO)2(CF3C2CF3)
were obtained; the cis isomer is slowly
transformed to the trans isomer at 160�. These complexes do not react further
with alkynes. Two other products were identified as an iridiocyclobutenone
complex and a iridiocyclopentadiene complex, viz.(η-C5H5){IrC(CF3)=C(CF3)CO}(CO)
and (η-C5H5){IrC(CF3)=C(CF3)C(CF3)}(CO)These complexes are also
inert to further reaction with hexafluorobut-2-yne, and the
iridiocyclopentadiene complex could not be converted into the cyclopentadienone
complex (η-C5H5)Ir{C4(CF3)4-CO).
The spectroscopic properties of a product of formula (η-C5H5)Ir(CF3C2CF3)2(C4HF5)
indicate it incorporates a 1-(2',2'-difluoroethenyl)-1,2,3,4,5-pentakis(trifluoromethyl)cyclopenta-2,4-diene
ligand. The final product was formulated as (η-C5H5)Ir2(CO)3(CF3C2CF3)2H
and five alternativestructures are consistent
with the spectroscopic data. The related reaction between (η-C5H5)Ir(CO)2 and but-2-yne
at 180� gives a small amount of hexamethylbenzene plus the maleoyl complex(η-C5H5){IrC(O)(Me=C(Me)C(O)}(CO).
Crystal Structure of Tris(1,10-phenanthroline)mercury(II) Trifluoromethanesulfonate
Authors: Deacon GB , Raston CL , Tunaley D , White AH
Published: September 2010

The crystal structure of
the ethanol solvate of the title compound, [Hg(phen)3](CF3S03)2
(phen =1,10-phenanthroline), has been determined at 295(1) K by single-crystal
X-ray diffraction and refined by least squares to a residual of 0�043 for 2939
'observed' reflections. Crystals are monoclinic: C2/c, a 25�25(1), b 10�960(4), c 18�949(6) �, β 129�32(2)�,
Z 4. The cation is centred on a crystallographictwofold axis and has
approximate D3 point
symmetry. The deviation of the mercury(II) environment from octahedral symmetry
toward the trigonal-prismatic limit is considerable, the mean trans N-Hg-N angle being 154�52�.  is 2�400
�. The unit cell volume is considerablydependent on
crystallization solvent, being larger for the ethanol solvate than for
solvent-free crystals obtained from aqueous solution.
Concentrations of Radicals During Reaction of Titanium(III) with Hydrogen Peroxide
Authors: Irvine MJ , Wilson IR
Published: September 2010

The concentrations of the
two radical species formed in this reaction are always very small by comparison
with those of the reactants and products. The radicals have quite different
dependences of concentration on time and thus are not even approximately in
equilibrium during reaction. The total rates of reaction agree well with those
predicted by a simple HO mechanism. The
perils involved when constant volume displacement pumps are used in flow
reactors areexemplified.
Some Physical Properties of Aqueous L-Ascorbic Acid Solutions
Authors: Shamim M , Khoo SB
Published: September 2010

The density, viscosity and
refractive index of aqueous L-ascorbic acid solutions, in the concentration range
0.01-1.20 M, have been measured at 25�C. The partial molal
volume of the undissociated acid at infinite dilution
has been found to be 105.74 cm3 mol-1. Equations which
describe the density and relative viscosity of the solutions have also been
given.
Regeneration of a Steroid C13 Angular Methyl Group from a Functionalized Precursor : Application to the Preparation of C 18-2H3 Steroids and C 18-2H3 D-Homosteroids
Authors: Blair IA , Frith RG , Phillipou G , Seaborn CJ
Published: September 2010

3β-Acetoxypregn-5-eno-18,20-lactone
has been converted into 3β,20β-dimethoxypregn-5-ene (6) by using
electrochemical deoxygenation of a C13 formyl intermediate as a key reaction. The electrochemicalreduction is also shown to
be applicable to multiple deuterium labelling of the C13 angular methyl group
in high isotopic purity.A facile preparation of 3β
-hydroxy-17α-methyl-D-homoandrost-5-en-17a-one (10) and its respective C18-2H3
analogue from the ether (6) is described.
(S)-( - )-Proline Catalysed Alkylation of 1,3-Dihydroxyanthraquinone with Phenylacetaldehyde
Authors: Castonguay A , Berger Y
Published: September 2010

In the presence of the
amino acid (S)-(-)-proline, 1,3-dihydroxyanthraquinone (1) is alkylated by phenylacetaldehyde to give an anomeric mixture of lactols (2). The lactols are
oxidized to the corresponding lactone (3) by manganese dioxide or chromic acid.
Treatment of (2) with p-toluenesulfonic acid yields the expected enol ether (4) along with the substitution product (5).
Mass spectrometry fragmentation, high-resolution 1H N.M.R. and 13C
n.m.r, studies of these compounds are discussed.
Crystal Structure of the Pyridinium Salt of the Polymeric Tris(thiocyanato)dicuprate(I) Anion
Authors: Raston CL , Walter B , White AH
Published: September 2010

The title compound, [C5H6N]+
[Cu2(SCN)3]-, has been prepared and its
crystal structure determined by single-crystal X-ray diffraction at 295(1) K.
Crystals are monoclinic, Cc, a 11.238(7), b 11.644(4), c 10.020(4)Ǻ,
β 102.67(3)°, Z 4, the structure being refined to a residual of 0.037 for
the 960 'observed' reflections. The structure comprises a three-dimensional
network of copper(I) atoms linked by bridging thiocyanate groups, the
pyridinium counterions occupying sites in the network cavities. Both copper atoms
are four-coordinate, one having an environment of one nitrogen atom [Cu-N,
1.926(9)Ǻ] and three sulfur atoms [Cu-S, 2.319(3), 2.421(3),
2.448(3)Ǻ], while the other is coordinated by two atoms of each type
[Cu-N, 1.935(9), 1.947(10); Cu-S, 2.430(3), 2.493(4) Ǻ].
A Convenient Method for Iodolactonization
Authors: Cambie RC , Ng KS , Rutledge PS , Woodgate PD
Published: September 2010

Iodo lactones are
conveniently prepared under neutral conditions by treatment of unsaturated
carboxylic acids with thallium(I) acetate and iodine in a non-polar solvent.
The crystal and molecular structure of (±)-('E')-N-Acetylpiperidine-2-carboxylic acid
Authors: Rae ID , Raston CL , White AH
Published: September 2010

The crystal structure of
N-acetylpiperidine-2-carboxylic acid has been determined by single-crystal
X-ray diffraction methods at 295(1) K and refined by least squares to a
residual of 0.039 for 846 'observed' reflections. Crystals are orthorhombic,
with space group Pbca, a 13.684(6), b 11.602(4), c
11.171(4)Ǻ, Z 8. The ring is a chair structure in which, contrary to an
earlier proposal based on 1H n.m.r. studies, there is almost perfect
staggering about the C(2)-C(3) bond.
Upper critical solution temperatures of hydrocarbon + fluorocarbon mixtures : mixtures with specific interactions
Authors: Toczylkin LS , Young CL
Published: September 2010

The upper critical solution
temperatures of a series of compounds with perfluorotributylamine
and with perfluorocyclohexene are reported. From
these results the interaction energy parameter, ξ, has been calculated by
using a hard sphere+attractive term equation of
state, together with the one-fluid model. The values of ξ for these
mixtures and a few calculated from literature upper critical solution
temperatures have been discussed in terms of possible specific interactions
between pairs of unlike molecules.
Tropolone-triethylamine equilibria in various solvents
Authors: Poh B , Siow H
Published: September 2010

Infrared and nuclear
magnetic resonance spectroscopic methods were used to study the tropolonetriethylamine equilibria. In aprotic solvents
tropolone transfers its proton to triethylamine to form an ion pair which is in
equilibrium with the intramolecularly hydrogen-bonded tropolone. The extent of
ion pair formation increases with the dielectric constant of the aprotic
solvent. Unlike the case of the p- nitrophenol-triethylamine
system, there is no formation of a hydrogen bonded complex between tropolone and
triethylamine. In the case of the tropolone-dibutylamine
system in aprotic solvents, only ion pair formation is observed.
Synthesis of analogues of GABA. IV. Three unsaturated derivatives of 3-aminocyclopentane-1-carboxylic acid
Authors: Allan RD , Twitchin B
Published: September 2010

cis-4-Aminocyclopent-2-ene-1-carboxylic
acid (4), 4-aminocyclopent-1- ene-1-carboxylic acid (5) and
3-aminocyclopent-1-ene-1-carboxylic acid (6) have been synthesized as conformationally restricted analogues of the inhibitory
neurotransmitter GABA.
Infrared spectroscopic studies of melt-deposited salt occlusion by zeolites
Authors: Petfield AT , Cooney RP
Published: September 2010

Sodium nitrate is occluded
by the zeolites NaX and NaA.
In addition to occluded nitrate, adherent nitrate appears to contribute to the
infrared spectra of most zeolite+NaNO3 systems. A lattice mode has
been detected for the system NaA+NaNO3, which is interpreted in
terms of an ordered occluded phase. Evidence indicates that both occlusion and
cation exchange occur in the system NaA+LiNO3. The extent of
occlusion of NaNO3 by NaX is much less
than by NaA. Interaction between the zeolitic cation
and the occluded phase is not significant even when the zeolitic cation is
strongly coordinating (e.g. Zn2+). Little, if any, KSCN is occluded
by zeolites NaA and NaX,
and KSCN appears to react on the internal surface of ZnX.
Crystal structure of sodium trans-bis(ethane-1,2-diamine)disulfitocobaltate(III) trihydrate
Authors: Fallon GDRCL , White AH , Yandell JK
Published: September 2010

The crystal structure of
the title compound, Na[Co(en)2(SO3)2],3H2O,
has been determined by single-crystal X-ray diffraction at 295(1) K and refined
by least squares to a residual of 0.068 for 1890 'observed' reflections.
Crystals are monoclinic, P21/c, a 8.481(3), b 13.661(6), c 13.715(6)
Ǻ, β 106.91(3)°, Z 4. The asymmetric unit of the structure contains
two independent anions, each located about a crystallographic centre of
symmetry. (Co-S) is 2.267 Ǻ, the longest Co-S distance so far
reported in cobalt(III)/sulfite complexes.
Micellar catalysed hydrolysis of amides. 4-Nitroacetanilide in hexadecyl-trimethylammonium bromide
Authors: O'Conner CJ , Tan A
Published: September 2010

Surface tension measurement
of the critical micelle concentration, CMC, of cationic
hexadecyltrimethylammonium bromide, ctab, shows a significant increase on
addition of very small amounts of 4- nitroacetanilide. At concentrations above
the CMC, ctab catalyses the hydrolysis of 4-nitroacetanilide.The micellar
catalysis is inhibited by added salts, especially those of arenesulfonates and
bulky carboxylate ions. The kinetics have been analysed in terms of competitive
binding of the substrate and the inhibitor to the micelle.
The reactivity of p-nitrophenyl esters with surfactants in nonaqueous solvents. I. p-Nitrophenyl acetate in benzene solutions of dodecylammonium propionate
Authors: O'Conner CJ , Ramage RE
Published: September 2010

The rate of decomposition
of p-nitrophenyl acetate, pnpa,
in benzene in the presence of dodecyl-ammonium propionate,
dap, has been measured at temperatures between 288 and 308 K. The proposed rate
equation consists of a term arising from micellar catalysis and a term arising
from a bimolecular reaction between the ester and the components of dap. Arrhenius parameters have been estimated for the two
reaction modes. Literature data related to similar reactions have been reviewed.
The reactivity of p-nitrophenyl esters with surfactants in nonaqueous solvents. III. The effect of altering the head-groups of alkylammonium carboxylates dissolved in benzene
Authors: O'Conner CJ , Ramage RE
Published: September 2010

The rate of decomposition
of p-nitrophenyl acetate, pnpa, has been measured in
benzene solutions of a series of alkylammonium
propionates, CH3(CH2),NH3+ -O2CCH2CH3
(where n = 3, 5, 7, 9 or 11), and a series of dodecylammonium
carboxylates, CH3(CH2)11NH3+
-O2C(CH2)mCH3 where m =
1, 2, 6 or 7). The micellar rate constant is affected by the alkyl chain
length. The bimolecular rate constant is affected by both the chain length and
the acidity of the head-groups. The reactivity of longer chain esters with dodecylammonium propionate is markedly less than that of pnpa.
Studies of Australian soft corals. XIX. Two new sesquiterpenes with the nardosinane skeleton from a Paralemnalia species
Authors: Bowden BF , Coll JC , Mitchell SJ
Published: September 2010

The isolation of two new
sesquiterpenes (3) and (4), related to the known sesquiterpenes lemnalactone(1)
and 2-deoxylemnacarnol (5), is reported from the soft coral Paralemnalia
thyrsoides. Their structures were deduced from spectroscopic data, and confirmed
by conversion into known sesquiterpenes. A semisystematic
nomenclature, based on the name 'lemnalan' for the trimethylperhydronaphtho[b]furan
(8) parent structure, is suggested.
A polarographic study of pyranopyrandiones
Authors: Tan S , Hsieh SAK
Published: September 2010

Polarographic reductions of
four methyl-substituted pyranopyrandiones (1)-(4) have been studied at various
pH values. Their reducibility and the probable reduction mechanisms are
discussed in relation to their structures. The half-wave potentials of their first
reduction waves in neutral media show linear correlation with the HMO energies
of the lowest vacant π molecular orbitals.
The self-condensation reactions of the lignin model compounds, vanillyl and veratryl alcohol
Authors: Hemmingson JA , Leary G
Published: September 2010

Self-condensation of the
lignin model compounds vanillyl and veratryl alcohol leads to the formation of
benzyl ether and diphenylmethane structures. It is
suggested that these structures may be formed within lignin as it ages in the
plant cell wall.
The infrared spectrum of solid sodium hydrogen bifluoride. Doubling of the HF stretching band of dilute NaHF2 in NaDF2
Authors: Spinner E
Published: September 2010

Infrared spectra (4000-200
cm-1) of discs in potassium iodide and mulls in paraffin and Fluorolube
have been measured for NaHF2 and NaDF2 (99%D), and a
range of isotopic dilutions. Stretching v3 of DF2-, as an
isotopic solid solute in NaHF2, appears as a single band with a
half-width of c. 50 cm-1, but v3 of HF2-
dissolved in NaDF2 has two components, separated by c. 62 cm-1
(relative intensities c. 5 : 3). For bulk NaHF2 the frequency
intervals in the sequence v3+nv1 are much smaller than v1,
and apparently irregular. The splitting of v3 of HF2-
is attributed to the F-H...F- ↔ F-...H-F
interconversion doubling which Ketelaar erroneously
believed to have detected (for KHF2) in 1941. The effect of high
isotopic dilution on frequency is straightforward for bending v2,
which is raised, but not for v3, which is raised (by c. 35 cm-1)
for HF2- in NaDF2, but lowered (by c. 75 cm-1)
for DF2- in NaHF2. This anomalous behaviour by
v3 is indicative of disorder of some kind.
Phosphorus-31 and Mercury-199 N.M.R. studies on mercury(II) halidetributylphosphine complexes
Authors: Colton R , Dakternieks D
Published: September 2010

Phosphorus-31 and
mercury-199 N.M.R. studies have been carried out on HgX2P2,Hg2X4P2,
mixtures thereof and the oligomers Hg2X4P3, Hg3X6P2
and Hg4X8P2 where X = Cl,
Br, I and P = tributyl-phosphine. The results are consistent with exchange of
both phosphine and halogen. The phosphine exchanges slowly on the N.M.R. time
scale at room temperature, but rapidly on the preparative time scale. Halogen
exchange is fast on both the N.M.R. and preparative time scales at room
temperature; cooling to -120°C reduces exchange of terminal halogens to a slow
rate on the n.m.r. time scale. Increase in the coupling constant JP,Hg
at low temperature is attributed to the slowing down of halogen exchange.
Exchange of bridging halogens is still fast at -120°C. ���
Mercury-199 chemical shifts span a range of
over 3000 ppm and shifts have been correlated with 31P
chemical shifts and with the coupling constants JP,Hg The
199Hg n.m.r. data confirm the existence of an asymmetrical isomer of
Hg2I4(PBu3)2.
Mechanisms of alkaline degradation of sucrose. Relative rates of alkaline degradation of some sucrose derivatives
Authors: Manley-Harris M , Moody W , Richards GN
Published: September 2010

An earlier study of the
relative rates of degradation of several sucrose derivatives has been refined
and extended. The results support a novel hypothesis to explain the unusual
alkali-lability of sucrose (1). In this hypothesis
the first and rate-determining step in the degradation is an SN1cB
displacement effected at the C1 anomeric centre of the glucose moiety by an
oxyanion derived from the C1' hydroxyl (10), to produce 1-(α-D-glucopyranosyl)fructose
(11). The latter is then very rapidly degraded, mainly to lactic acid. The
possibility of analogous competing displacements involving the 3' and 6'
oxyanions remains for further investigation.
The alkaloids of Symphytum × uplandicum (Russian comfrey)
Authors: Culvenor CCJ , Edgar JA , Frahn JL , Smith LW
Published: September 2010

Eight pyrrolizidine
alkaloids have been identified in the leaves of Symphytum
× uplandicum Nyman (Russian comfrey). They are
echimidine (1), symphytine (2), lycopsamine (3), intermedine (4) and four new alkaloids, 7-acetyllycopsamine
(5), 7-acetylintermedine (6), symlandine (7)(7-angelyl-9-viridiflorylretronecine)
and uplandicine (8) (7-acetyl- 9-echimidinylretronecine).
Bis-s-triazolo[1,5-a:1',5'-c]pyrimidine and some simple derivatives
Authors: Brown DJ , Shinozuka K
Published: September 2010

A general synthetic route
to the new tricyclic system bis-s-triazolo[1,5-a: 1',5'-c]pyrimidine,
is reported. Thus the parent heterocycle (11a) is
prepared from the key bicyclic intermediate, s-triazolo[1,5-c]pyrimidin-5-ylamine
(7a), through the corresponding 5- dimethylaminomethyleneamino
(8a), 5-hydroxyaminomethyleneamino (9a) and 5-acetoxyaminomethyleneamino (10a)
derivatives, followed by final cyclization. Its 8-methyl (11b), 8-phenyl (11c),
5-methyl (11d), 5,8-dimethyl (11e) and
5-methyl-8-phenyl (11f) derivatives are prepared rather similarly. Structures are
confirmed by n.m.r. spectra.
Dehydrogenation of the alkane chain of 1,3-bis[2-(diphenylphosphino)phenyl]-propane on a rhodium(I) centre. Complexes of the resulting olefinic ligand with rhodium(I), iridium(I), rhodium(III) and nickel(II)
Authors: Bennett MA , Neumann H
Published: September 2010

The title compound, o-Ph2PC6H4(CH2)3C6H4PPh2-o
(5), has been synthesized in three steps, starting with the Fe2(CO)9-promoted
conversion of 2- bromobenzyl bromide into 1,3-di(2-bromo-phenyl)propan-2-one,
o- BrC6H4CH2COCH2C6H4Br-o.
Compound (5) undergoes dehydrogenation on reaction with the cycloocta-1,5-diene
(cod) complex [RhCl(cod)]2 to give a rhodium(1) complex
[RhCl((E)-o-Ph2PC6H4CH=CHCH2C6H4PPh2-o)]
(9), in which the olefin and mutually trans phosphorus atoms are bound to the
metal. The tridentate ligand (E)-o-Ph2PC6H4CH=CHCH2C6-
H4PPh2-o (4) can be liberated from (9) by treatment with
sodium cyanide, the overall yield based on 2-bromobenzyl bromide being about 17
%. On reaction with the chlorides of rhodium(III) or nickel(II), (4) loses a
methylene proton to give chelate η3-allylic complexes RhCl2(o-Ph2PC6H4CH=CH=CHC6-
H4PPh2-o) (11) and NiCl(o-Ph2PC6H4CH=CH=CHC6H4PPh2-o)
(13) respectively. The proposed structures for the new complexes are based on
i.r. and N.M.R. (1H, 31P) data, and also on a comparison
with similar complexes formed by the known tridentate ligand (E)-o-Ph2PC6H4CH=CHCHMeC6-
H4PPh2-o (2). Conformational isomers of the rhodium(I)
complex (9) and its iridium(I) analogue (10) formed from ligand (4) cannot be
detected by n.m.r, spectroscopy, in contrast with the corresponding complexes
formed by ligand (2).
The Meisenheimer rearrangement in heterocyclic synthesis. II. Synthesis and X-ray crystal structure of a tetrahydro-1H-2,3-benzoxazocine and preparation of a hexahydro-2,3-benzoxazonine
Authors: Bremner JB , Browne EJ , Davies PE , Raston CLWAH
Published: September 2010

The heterocyclic derivatives,
8,9-dimethoxy-3-methyl-1-phenyl-3,4,5,6- tetrahydro-1H-2,3-benzoxazocine(3a)
and 9,10-dimethoxy-3-methyl-1- phenyl-1,3,4,5,6,7-hexahydro-2,3-benzoxazonine
(3b),examples of two new ring systems, have been prepared by Meisenheimer
rearrangement of the corresponding 2-benzazepine and 2-benzazocine N-oxide
derivatives (2a) and (2b). The Bischler-Napieralski-type
cyclization reaction was used in the preparation of the tertiary amine
precursors of these N-oxides reaction conditions for the cyclization were
critical and phosphorus oxychloride in refluxing butanenitrile was found to
give the best yields of the seven- or eight-membered cyclic imine
intermediates. Reductive cleavage of the benzoxazocine derivative (3a) with
zinc in acetic acid followed by N-methylation gave the expected product, [2-{3-
(dimethylamino)propyl}-4,5-di-methoxyphenyl]phenylmethanol (12). The crystal and molecular structure of
(3a) has been determined by X-ray crystallographic analysis.
The Meisenheimer rearrangement in heterocyclic synthesis. III. Derivatives of the 1H-[1,2]oxazepino[6,5-b]indole, thieno[2,3-e][1,2]oxazepine and [l]benzothieno[3,2-e][1,2]oxazepine ring systems
Authors: Bremner JB , Browne EJ , Davies PE
Published: September 2010

The new heterocyclic
derivatives 3-methyl-1-phenyl-3,4,5,10-tetrahydro- 1H-[1,2]oxazepino[6,5-b]-indole
(5c), 6-methyl-4-phenyl-4,6,7,8- tetrahydrothieno[2,3-e][1,2]oxazepine (6f),
and 3-methyl-1-phenyl- 1,3,4,5-tetrahydro[1]benzothieno[3,2-e][1,2]oxazepine
(7c) were prepared in good yield by thermal Meisenheimer rearrangement of the
corresponding tertiary amine N-oxide precursors. No such rearrangement occurred
on heating the N-oxides of the fused bicyclic systems
2,3,11,12-tetramethoxy-5,8,9,13b-tetrahydro-6H-dibenzo[a,h]quinolizine (3) and
8,9-dimethoxy-1,2,3,5,6,10b-hexahydropyrrolo[2,1-a]isoquinoline (4). The
reduction of (5c), (6f) and (7c) with zinc in acetic acid is also described.
Contributions from dielectric inhomogeneity to the free energy of ionic solvation
Authors: Stiles PJ
Published: September 2010

A new dielectric profile
for the solvent dielectric constant beyond the primary coordination or solvation
sphere is used to show that neglect of dielectric inhomogeneity by the Born
treatment can lead to significant overestimation of ionic solvation energies.
Conversion of enones into dienones via allylpalladium complexes
Authors: Haynes RK , Jackson WR , Stragalinou A
Published: September 2010

A series of reagents for
the conversion of enones into dienones via allylpalladium compounds has been
studied and mild conditions for dienone preparation are recommended.
Ab initio studies on amides: conformational preferences of formimide and barriers to interconversion of the conformers
Authors: Radom L , Riggs NV
Published: September 2010

Formimide (diformamide),
the parent of the diacylamines, is capable of existing in three basic
ground-state conformations about the N-C bonds. Full geometry optimization with
the STO-3G basis set predicts that all three conformers are fully coplanar,
that the E,E (1) and E,Z(3) conformers are of similar energy, and that the Z,Z
(2) conformer is of somewhat higher energy (by 11 kJ mol-1); 4-31G
evaluation of the energies suggests that (2) is by far the least stable and
that (1) is of higher energy than (3) by 6.5 kJ mol-1. Analysis of
the calculated charge distribution suggests that (2) is destabilized by
electrostatic repulsion. These results are consistent with experimental
conclusions that planar (3) is strongly preferred in the vapour state at room
temperature and that (2) has not been observed in the vapour state or in
solution. Partial geometry optimization with the STO-3G basis set of model
transition states for internal rotation suggests a barrier height of 52 kJ mol-1
(72 kJ mol-1 when evaluated with the 4-31G basis set) for the conversion
(3) → (1).
Phosphorus-31, cadmium-111, cadmium-113 and mercury-199 N.M.R. studies of cadmium(II) halide and mixed cadmium(II)-mercury(II) halide complexes with tributylphosphine
Authors: Colton R , Dakternieks D
Published: September 2010

Phosphorus-31, cadmium-111
and cadmium-113 n.m.r, studies have been carried out on CdX2(PBu3)2
(where X = Cl, Br, I). The results are consistent
with exchange of both phosphine and halogen. Phosphine exchange becomes slow on
the N.M.R. time scale in all cases by -40°C. Mixtures of CdX2(PBu3)2
with different halogens give averaged signals at room temperature, but below
about -80°C exchange becomes slow and halogen redistribution reactions can be
observed. ��� Reaction of CdX2 and PBu3
in 1 : 1 proportions in ethanol gives Cd2X4(PBu3)3
as the isolated product, not Cd2X4(PBu3)2.
It is shown that ethanol is an effective ligand to cadmium and redistribution
reactions between coordinated ethanol and the phosphine occur. ��� The mixed metal complexes CdHgX4(PBu3)2
have been shown by phosphorus-31, cadmium-113 and mercury-199 n.m.r, studies to
have all the phosphine coordinated to mercury. ��� Cadmium-111 and cadmium-113 chemical shifts
in these compounds span a range of over 500 ppm and
shifts have been correlated with 31P chemical shifts and the
coupling constant JP,Cd.
Defect density in a metal-monolayer-metal cell
Authors: Peterson IR
Published: September 2010

Techniques for Langmuir-Blodgett monolayer deposition at high surface
pressures and with minimum deformation have been studied by measurement of the
resultant defect densities in a metal-monolayer-metal cell.