A linear potassium metalated vanadium(IV) polymeric alkoxide: Structural and spectroscopic studies

We have been interested in the preparation of alkoxometallate “bricks” of the M′{M(OR)n} type, with M′ = alkaline metal, M = vanadium(IV) and R = isopropyl or tert-butyl, to be employed as starting materials in salt-elimination reactions with other transition metal complexes. Here, we report the synthesis, spectroscopic characterisation and molecular structure of [{K2(VO)2(OPri)6(PriOH)2}∞] (1), prepared by a combination of Lewis acid–base and micro-hydrolysis reactions. The linear polymeric chain contains planar four-membered {(Vdouble bond; length as m-dashO)2(μ-OPri)2} rings with vanadyl groups in anti-coplanar configuration; the rings are connected by “bridging” K(HOPri)+ units. Powder and solution EPR spectra suggest a spin triplet ground state, with a very weak ferromagnetic interaction between the vanadium(IV) centres at room temperature.