Multielectron Redox Process of Vanadium Complexes in Oxidation of Low-Coordinate Vanadium(III) to Oxovanadium(V) with Dioxygen

Electroreduction of a vanadium dinuclear complex [(salen)VIVOVIV(salen)]2+ in the presence of O2 resulted in the stoichiometric formation of a [(salen)VIVOVV(salen)O]+ complex. The process provided not only evidence for the interconversion of vanadium(III)/oxovanadium(V) in the action of vanadium complexes operating as redox catalysts, but also possibilities for the use of the vanadium complex as electrocatalysts for the 4-electron reduction of O2.