Premium
Kinetics of Oxidation of L ‐Cysteine by trans ‐ and cis ‐Co III and Fe III Complexes based on α‐ and γ‐Diimine Schiff Base Ligands
Author(s) -
AbdelHalim Hamzeh M.,
AbuSurrah Adnan S.,
Baker Hutaf M.
Publication year - 2010
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200900480
Subject(s) - chemistry , diimine , reaction rate constant , metal , schiff base , steric effects , kinetics , ionic strength , metal ions in aqueous solution , absorbance , aqueous solution , ionic bonding , chemical kinetics , inorganic chemistry , medicinal chemistry , ion , stereochemistry , organic chemistry , catalysis , chromatography , physics , quantum mechanics
Kinetics of oxidation of L ‐cysteine by Co III and Fe III complexes based on α‐ and γ‐diimine Schiff base ligands were studied in aqueous solution. Pairs of trans and cis isomers of the metal complexes were used in the studies. Kinetic measurements were performed at 25 °C and constant pH and ionic strength under pseudo‐first order condition, in which the concentration of cysteine was around two orders of magnitude greater than that of the metal complex. The observed rate constant was obtained by following the change in absorbance of the reaction mixture with time at a predetermined wavelength. The overall rate constant and order of the reaction with respect to cysteine and metal complex were determined. For both metal ions studied, the oxidation rate constant for the trans isomer was higher than that for the cis isomer. This was attributed to the contribution of the steric factor and the trans effect. The effects of substituents and the nature of the metal ion on the reaction rate are discussed.