Kinetics and mechanisms of the reactions of thiosulphato-amine complexes of cobalt(III). Part II. Base hydrolysis of the bis(ethylenediamine)thiosulphatocobalt(III) ion

Abstract

Base hydrolysis of the bis(ethylenediamine)thiosulphatocobalt(III) was investigated spectrophotometrically between 35 and 65 °C and with base concentrations (NaOH) up to 2.0 mol dm−3. The hydrolysis consists of a one-stage reaction, followed by a slow dechelation step, and then by a fast ligand loss. The reaction is base-dependent. The products of the reaction are an equilibrium mixture ofcis- andtrans-Coen2 (OH) 2 + . Activation parameters for the reaction as determined by the Eyring equation, are ΔH†=77.8±4.6 kJ mol−1 and ΔS†=−75±20 JK−1 mol−1.