Thermodynamic and kinetic effects of the organic group in the electrochemical reduction of organocobaloximes

Abstract

The electrochemical reduction of alkylcobaloximes at the dropping mercury electrode involves an initial one electron transfer process to give a radical anion with the cobalt in the Co II formal oxidation state. The CoC bond cleavage in the radical anion is an homolytic process yielding the Co I cobaloxime and competing with a second electron transfer. The nature of the organic group and of the solvent coordinated in the trans position to the Co atom influences the thermodynamics of the electron transfer and the stability of the radical anion. Electronic and steric effects on the thermodynamics of the first electron transfer can be distinguished. These effects have only a small influence on the kinetics of the first electron transfer.