Redox Chemistry in the Reaction of Oxovanadium(V) with Thiolate-Containing Ligands: the Isolation and Characterization of Non-Oxo Vanadium(IV) Complexes Containing Disulfide and Thioether Groups

The reactions of VVO(O‐iPr)3 with [PS3′]H3 and [PS3]H3 {[PS3′]H3 = P(C6H3‐5‐Me‐2‐SH)3, [PS3]H3 = P(C6H4‐2‐SH)3} led to the formation of [VIV(L)] [L = P2S4′ (1a), P2S4 (1b)], where L was formed by the oxidative coupling of two PS3′ or PS3 ligands by a disulfide bond. When the reaction of VVO(O‐iPr)3 with [PS3′]H3 was conducted in the presence of methoxide followed by the addition of a cation, [VIV(PS3′)(PS2SMe′)]X [X = N(C2H5)4 (2a), N(C2H5)3(CH2Ph) (2b)] was isolated, where PS2SMe′ is a bis(benzenethiolato)phenylmethylthioetherphosphane ligand generated from the methylation of one thiolate group in PS3′. The structures of complexes 1a,b and 2a,b, determined by X‐ray crystallography, contain six‐ and seven‐coordinate non‐oxo vanadium(IV) centers, respectively, with an octahedral geometry for 1a,b and a pentagonal‐bipyramidal geometry for 2a,b. The electronic, magnetic, and electrochemical properties of these complexes were determined by UV/Vis and EPR spectroscopy, SQUID measurements, and cyclic voltammetry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)