Low-valent vanadium catecholateclusters

Abstract

A simple synthetic route to low-valent vanadium catecholate clusters, via solvothermal reaction of [V(acac)₃] with catechols in alcohols, is presented. The syntheses and X-ray structures of [V^III₆O(dbcat)₄(OMe)₈(MeOH)₂] (1; which has the Lindqvist structure), [V^III₆O₂(dbcat)₂(dbsq)₂(acac)₂(PhCO₂)₄(EtO)₂] (2; which could alternatively be formulated as [V^III₄V^IV₂O₂(dbcat)₄(acac)₂(PhCO₂)₄(EtO)₂]) and [V^IV₂(dbcat)₄(EtOH)₂] (3) are reported (dbcat²⁻ = 3,5-^tBu₂-catecholate; dbsq⁻ = 3,5-^tBu₂-semiquinone). The X-ray structures of the primary products of the reactions of 1 and 3 with atmospheric oxygen, [V₆O₃(“dbcat”)₄(OMe)₈] (4) and [V₂O₂(“dbcat”)₄] (5), are also reported—the assignments of redox states for these four-electron oxidised species are more ambiguous.