Electrochemical oxidation of nickel-phosphine complexes of the type [NiII(.eta.5-C5Ph5){Ph2PCH:C(O)R}] (R = Ph, ferrocenyl). Direct and indirect generation of nickel(III) and nickel(II)-cation radical species

Abstract

The electrochemical oxidation of [Ni II (η 5 -C 5 Pb 5 ){Pb 2 PCH=(O)Ph}] (1) and [Ni II (η 5 -C 5 Pb 5 ){Pb 2 PCH=C(O)Fc}] (Fc=Ferrocenyl group) (2) has been investigated in dichloromethane by rotating disk voltammetry, cyclicvoltammetry, thin-layer spectroelectrochemistry, and ESR spectroscopy. At a platinum electrode, 1 undergoes a reversible one-electron oxidation whereas the oxidation of 2 proceeds by two successive reversible one-electron steps