Keith L. Scott

DOES SOCIAL DEPRIVATION DURING GESTATION AND EARLY LIFE PREDISPOSE TO LATER SCHIZOPHRENIA

SummaryWe employed a case-control study design to investigate whether schizophrenic patients differed from non-psychotic psychiatric patients in terms of place of birth and paternal occupation. “Cases” were first-contact schizophrenic patients ascertained from the Camberwell Cumulative Psychiatric Case Register. “Controls” were the next (non-psychotic) patient on the Register matched for age and sex. In comparison with controls, cases were more likely to have: (1) been born in the deprived innercity Camberwell catchment area (odds ratio 2.3), and (2) had fathers who had “manual” as opposed to “non-manual” occupations (odds ratio 2.1). The results were compatible with the notion that socio-economic deprivation during gestation and early life predisposes to later schizophrenia.

The Cr2+ and V2+ reduction of µ-carboxylato-dicobalt(III) ammine complexes. Part V. The mechanism of reduction of µ-maleato- and µ-fumarato-complexes

The Cr2+ and V2+ reductions of binuclear cobalt(III) complexes [(NH3)4Co·µ(NH2, maleato)·Co(NH3)4]4+, [(NH3)3Co·µ(OH,OH, maleato)·Co(NH3)3]3+, and [(NH3)3Co·µ(OH,OH,fumarato)·Co(NH3)3]3+, referred to as µ(am), µ(hhm), and µ(hhf) respectively, proceed by a slow/fast reaction sequence. Kinetic data have been obtained for the first stages with Cr2+ as reductant and at 25 °C, I= 1.0M(LiClO4), second-order rate constants (l mol–1 s–1), enthalpies of activation (kcal mol–1), and entropies of activation (cal K–1 mol–1), are respectively for µ(am), 0.59, 5.5, and –41.3; µ(hhm), 1.87, 4.3, and –43.0; and µ(hhf), 2.64, 2.8, and –47.1. Rate constants are independent of [H+] in the range 0.02–1.00M. Product analyses are consistent with inner-sphere mechanisms involving remote attack. With V2+ as reductant kinetic data for the first stage are respectively for µ(am), 1.46, 9.8, and –24.9; µ(hhm), 0.164, 5.8, and –42.3; and µ(hhf), 0.099, 75. and –38.0. No dependence on [H+] was observed except in the V2+ reduction of µ(hhm), when significant contributions were obtained from an [H+]–1 term with kinetic parameters, 0.45 (s–1), 10.6, and –29.3.

Preparation and characterisation of cis- and trans-tetra-amminebis(sulphito)cobaltate(III) anions and the kinetics of redox decomposition aqueous acid solution

In aqueous sulphite solution, trans-[Co(NH3)4(H2O)(SO3)]+ rapidly forms the bis(sulphito) complex which has been isolated as an unstable yellow solid, trans-Na[Co(NH3)4(SO3)2],2H2O. The cis-isomer has been prepared as the brown salts cis-Na[Co(NH3)4(SO3)2],2H2O and cis-NH4[Co(NH3)4(SO3)2],3H2O. I.r. and u.v.–visible spectra are reported. The latter are in disagreement with literature spectra and cis–trans-assignments based on them are reversed. In perchloric acid solution, aquation of ligands trans to sulphite results in rapid formation of trans-[Co(NH3)4(H2O)(SO3)]+ and [Co(NH3)2(H2O)2(SO3)2]– from the trans- and cis-isomers respectively. Rate constants, kobs, for redox decomposition of the cis-isomer under air-free conditions are of the form (i) at [H+]= 0·02–0·20M; at 20·0 °C and I= 1·00M(LiClO4), k=(1·39 ± 0·02)× 10–2 l mol–1 s–1, ΔH‡= 26·5 kobs=k[H+]+kI(i)± 0·4 kcal mol–1, and ΔS‡= 23·4 ± 1·3 cal K–1 mol–1. The acid-independent term contributes only ca. 3% of the observed rate at 0·1M-HClO4.

Reduction of tetranuclear µ-oxalato-cobalt(III) complexes by the ions chromium(II) and vanadium(II)

The kinetics of reduction of three highly charged tetranuclear µ-oxalato-cobalt(III) complexes by the ions Cr2+ and V2+ have been studied. All four cobalt(III) centres of each complex are reduced and the first stage of reaction is rate determining. Second-order rate constants kCrand kv for the chromium(II) and vanadium (II) reactions have been obtained and the ratios kCr : kv at 25 °C are 0·022, 0·017, and 0·020. It is concluded that the mechanism of reduction is in each case outer sphere. Activation parameters have been determined for the Cr2+ reduction of two of the complexes, and the magnitude of these parameters is discussed.

Mixed iron–cobalt binuclear complexes. Part I. Identification of mixed complexes derived from trans-[Co(en)2(H2O)(SO3)]+

Products from the reactions of the complex trans-[Co(en)2(H2O)(SO3)]+(en = ethylenediamine) with the ions [Fe(CN)6]4–, [Fe(CN)6]3–, [Co(CN)6]3–, and [Fe(CN)5NO]2– in aqueous solution are µ-cyano-complexes which have been characterised by means of their visible and i.r. spectra.

Mixed iron–cobalt binuclear complexes. Part II. Kinetics of formation and dissociation of binuclear complexes obtained from trans-aquabis(ethylenediamine)sulphitocobalt(III) and cyano-complexes of iron

The rate of reaction (i) has been studied by stopped-flow spectrophotometry. The rate law (ii) is obeyed at [FeII(CN)5(NO)]2–+[CoIII(en)2(SO3)(OH2)]+ [graphic omitted] [(ON)(NC)4FeIICNCoIII(en)2(SO3)]–(i)-d[Co]/dt =kt[Co][Fe](ii) pH 0–6 and 25·0 °C : kt= 700 ± 15 I mol–1s–1;ΔH‡= 59·8 ± 0·4 kJ mol–1; and ΔS‡= 10·5 ± 2·1 J k–1 mol–1[I= 1·00M(LiClO4)]. With [Fe(CN)6]3– and [Fe(CN)6]4– as reactants, rate parameters are kt= 1 725 ± 35 and 7 450 ± 220 I mol–1s–1, ΔH‡= 60·7 ± 0·8 and 56·9 ± 1·3 kJ mol–1, and ΔS‡= 21·3 ± 2·5 and 19·7 ± 3·3 J K–1 mol–1, respectively. The rate of the reverse of reaction(i) has been measured by following the displace [(ON)(NC)4FeIICNCoIII(en)2(SO3)]–+[FeIII(CN)6]3– [graphic omitted] [(NC)5FeIIICNCoIII(en)2(SO3)]2–+[FeII(CN)5(NO)]2–(iii) ment reaction (iii) which is first order in the concentration of the reacting binuclear complex and independent of the [Fe(CN)6]3– concentration : at 25·0 °C, kd= 0·113 ± 0·006 s–1[I= 1·00M(LiClO4)]. The dissociation rate constant for the complex [(NC)5CoIIICNCoIII(en)2(SO3)]2– has been obtained similarly: Kd=(3·41 ± 0·03)× 10–2 s–1 under the same conditions. A study of the rate of attainment of equilibrium (iv) in alkaline solution has [FeII(CN)6]4–+[CoIII(en)2(SO3)(OH)]⇌[(NC)5FeIICNCoIII(en)2(SO3)]3–+ OH–(iv) enabled kd for the dissociation of [(NC)5FeIICNCoIII(en)2(SO3)]3– to be obtained: kd=(2·56 ± 0·12)× 10–3 s–1 at 25·0 °C [I= 1·00M(NaClO4)]. Equilibrium constants for the formation of these binuclear complexes have been calculated from the kinetic data.

Redox decomposition of trans-tetra-ammineaquosulphitocobalt(III) in aqueous solution

The complex trans-[Co(NH3)4(H2O)(SO3)]+ decomposes to Co2+ in aqueous acid solution. Kinetic plots exhibit an initial period of curvature followed by a first-order process, kobs=(1·14 ± 0·03)× 10–4 s–1 at 25·0 °C, ΔH‡= 26·5 ± 0·1 kcal mol–1, and ΔS‡= 12·5 ± 0·4 cal K–1 mol–1[I= 1·00M(LiClO4)]. The rate of reaction is independent of [H+] in the range 0·01–1·00M. A mechanism is proposed relating kobs to a rate-determining isomerisation to the cis-complex, followed by rapid conversion to the complex [Co(NH3)3(H2O)2(SO3)]+ which probably undergoes an internal redox reaction. Somewhat higher rates have been observed in the presence of molecular oxygen and evidence is presented for formation of the free radical HSO3.

Reactions of µ-hydroxo-dicobalt(III) complexes. Part XIII. Further kinetic studies on the reaction of thiocyanate with the µ-amido-µ-hydroxo-bis[tetra-amminecobalt(III)] complex

Further studies have been made on the reaction of the µ-amido-µ-hydroxo-bis[tetra-amminecobalt(III)] complex with a large excess of thiocyanate, (i), in aqueous perchloric acid solutions I= 2.0 M(NaClO4). [graphic omitted] + H++ 2NCS–→ [graphic omitted] + H2O (i) Hydroxo-bridge cleavage is observed, where the concentration dependence of pseudo-first-order rate constants, kobs, at low [H+] and [NCS–] is of the form (ii), with k2 small and negligible at high [H+] and [NCS–]. kobs=k1[H+][NCS–]+k2[NCS–](ii) A non-linear dependence on hydrogen-ion concentration has to be taken into account with [H+] 0.5M. At 25 °C, k1=(4.7 ± 0.1)× 10–4 I2 mol–2 s–1, and activation parameters are ΔH‡1= 17.5 ± 0.4 kcal mol–1 and ΔS‡1=–14.7 ± 1.4 cal K–1 mol–1.