Kinetics and Mechanistic Studies of Oxidation of a Ternary Nitrilotri-Acetatocobalt(II) Complexes Involving DL-valine and DL-aspartic Acid as a Secondary Ligands by Periodate

Abstract

Oxidation of ternary complexes, [CoII (NTA)(L)(H2O)X]-n by periodate in aqueous medium has been studied spectrophotometrically over the (25.0 – 45.0) ± 0.1°C range. The reaction show first order kinetics with respect to both [IO4-] and the complexes, and the rate of the reaction increases over the [H+] range (1.05 – 28.20) x 10-5 mol dm-3 in both cases. Preparation and characterization of [CoII (NTA)(Asp)(H2O)2]-3 and [CoII (NTA)Val(H2O)2]2- is performed. Conformation of the formation of the ternary complexes has been done using IR spectrum, TGA, UV‐visible spectroscopic and cyclic voltammetry measurements. The thermodynamic activation parameters have been calculated. It is assumed that electron transfer takes place via an inner-sphere mechanism.