14040-33-6Relevant articles and documents
Stereochemical studies of cobalt ethylenediamine complexes and their tetrathionate salts: Interactions between complex configuration and tetrathionate conformation
Casadesus, Meritxell,Coogan, Michael P.,Davies, Elenna,Ooi, Li-ling
, p. 63 - 78 (2008/10/09)
A range of chiral coordination complexes of the formulae cis-[Co(en)2XY] where X, Y = hal, NH3, NO2, ox, SCN have been prepared as the halide or pseudohalide salts, and the novel examples have been structurally characterised and their stereochemical behaviour studied. Salt metathesis of certain of these species to the corresponding tetrathionates is described, and the tetrathionates structurally characterised and the stereochemical relationship between the conformations of the chiral complexes and the pseudochiral tetrathionates analysed. The patterns of cation-cation and cation-anion interactions are discussed in the context of the reported ability of the tetrathionate ion to induce conglomerate crystallisation in such species, and tetrathionate chirality in the literature.
Kinetics of the oxidation of L-cysteine by trans- and cis-cobalt(III) and iron(III) complexes
Abdel-Halim, Hamzeh M.,Abu-Surrah, Adnan S.,Baker, Hutaf M.
, p. 1346 - 1350 (2008/09/18)
Kinetics of oxidation of L-cysteine by pairs of trans and racemic cis isomers of cobalt(III) and iron(III) based transition metal complexes have been studied in aqueous solution. Kinetics measurements were run under pseudo first order conditions in which the concentration of cysteine is between one and two orders of magnitude greater than that of the isomers of the transition metal complex. The orders of the reaction with respect to both cysteine and the isomer were determined. The observed rate constants and the overall rate constants of the oxidation process were measured. For all geometrical isomers, it was found that the rate constant of oxidation of L-cysteine by the trans isomer is between one to three orders of magnitude greater than that by the CM isomer. The difference in rates can be explained by a geometric factor around the metal ion center in the complex. The less crowded isomer (trans) makes electron transfer easier and hence facilitates the oxidation process which leads to a higher oxidation rate.
Temperature programmed decomposition of cobalt ethylene diamine complexes
Dash,Ajikumar,Kamruddin,Tyagi
, p. 141 - 148 (2008/10/09)
The cobalt co-ordination complexes, [Co(en)2Cl2]Cl and [Co(en)2CO3]Cl, synthesised through literature procedures, were characterised by FTIR. Trace metallic impurities were determined by ICP-MS. Crystallinity of the samples were ascertained by preliminary X-ray powder diffraction analysis. Dark field polarised optical microscopy (OM) was used to observe particle size distribution. These compounds were subjected to temperature programmed decomposition (TPD) in thermogravimetric analyser (TGA). TPD was also carried out in a home built mass spectrometry based evolved gas analyser (EGA-MS). The complex TGA weight loss profile could be successfully explained through EGA data. Complimentary information received from both the above techniques indicated sequential decomposition, prevalence of steric effect and functional group ejection. The non-isothermal kinetic analysis of TGA and EGA data showed dominance of kinetic control mechanisms based on sigmoidal rate laws like Avarami-Erofeev (AE) and random nucleation (RN). The fraction release α ~ T plots were used to evaluate integral model function g(α) of non-isothermal kinetic rate expressions. From log[g(α)/T2] ~ 1/T plots of well correlated model functions, Arrhenius parameters like activation energy and pre-exponential factors were evaluated for various decomposition steps.
