Non-oxido divanadium(iv) and divanadium(v) thiolate complexes with a new type of chalcogenide bridging motif

Abstract

In our effort to study vanadium chalcogenide chemistry, we have synthesized and characterized a class of non-oxido divanadium(IV) and divanadium(V) complexes with chalcogenide and dichalcogenide as bridges. All structures consist of a similar divanadium motif, in which two metal centers are bridged by one μ-chalcogenide and one μ–η²:η²-dichalcogenide, forming a V₂(μ-E)(μ–η²:η²-E₂) (E = S or Se) core structure. These compounds are [V^IV₂(PS3)₂(μ-Se₂)(μ-Se)][PPh₄]₂ (1), [V^V₂(PS3′′)₂(μ-Se₂)(μ-Se)] (2), [V^V₂(PS3′′)₂(μ-S₂)(μ-S)] (3a) and [V^V₂(PS3)₂(μ-S₂)(μ-S)] (3b) ([PS3]³⁻ = P(C₆H₄-2-S)₃ and [PS3′′]³⁻ = P(C₆H₃-3-SiMe₃-2-S)₃). Compound 1 exhibits diamagnetic behavior, indicating strong antiferromagnetic coupling between two d¹ centers. Compounds 2 and 3a–b have the highest oxidation states for vanadium ions (+5/+5) among those reported divanadium chalcogenide clusters. The work demonstrates that high-valent divanadium chalcogenide clusters can be obtained with the activation of elemental chalcogens by low-valent vanadium ions.