An eight-coordinate vanadium thiolate complex with charge delocalization between V(V)-thiolate and V(IV)-thiyl radical forms

A six-coordinate oxovanadium(V) thiolate complex and an eight-coordinate non-oxovanadium thiolate complex, [PPh(4)][VO(PS3')(OCH(3))] (1) and [NEt(4)][V(PS3')(2)] (2) (PS3' = P(C(6)H(3)-3-Me(3)Si-2-S)(3)(3-)), respectively, have been isolated and structurally characterized. The former belongs to a limited collection of oxovanadium(V) thiolate complexes. The latter has an unusual coordination number of eight. More importantly, its consensus electronic structure derived from its spectroscopic data should be considered as the resonance forms of V(V)-thiolate and V(IV)-thiyl radical species. This implies that V(IV)-thiyl radical can maintain a stable presence in biological systems.