Electrochemical Confirmation of Disproportionate of μ-Oxo-bis[(N,N′-ethylenebis(salicylideneaminato))vanadium(IV)] Tetrafluoroborate

Abstract

μ-Oxo-bis[(N,N′-ethylenebis(salicylideneaminato))vanadium(IV)] tetrafluoroborate is prepared from (N,N′-ethylenebis(salicylideneaminato)) oxovanadium(IV) (VO(salen)) through an electrophilic reaction by triphenylmethyl tetrafluoroborate (Ph3CBF4) in dichloromethane. The voltammetric analysis of the binuclear complex in dichloromethane revealed a one-step two-electron transfer at 0.58 V (vs Ag/AgCl) based on the disproportionation (2VIVOVIVIIIOVIV + VIVOVV).V

Vanadium in Modern Organic Synthesis

“…During this step, an aryl sulfide is oxidatively dimerized to the sulfonium 81 , and molecular oxygen acts as an electron acceptor . A vanadium μ-oxo complex has been identified as a key oxidant in this coupling reaction (Scheme ) 41 …”

Aerobic Oxidation of Hydroquinones to Quinones Catalyzed by VO(acac)2

“…The oxidative reaction may start from a partial disproportionation of oxovanadium(IV) complex to the corresponding vanadium(III) and vanadium(V). 16 Vanadium(V) complex oxidizes hydroquinone to the corresponding quinone and becomes vanadium(III). Then, molecular oxygen oxidizes vanadium(III) to vanadium(V) and generates one mole of hydrogen peroxide.…”