Tri-, tetra- and octa-metallic vanadium(III) clusters from new, simple starting materials: interplay of exchange and anisotropy effects

The crystal structure of the monomeric vanadium(III) species mer-[V(bipy)Cl3(MeCN)] (1; bipy = 2,2′-bipyridine) is reported. The solvothermal reaction of [V(bipy)Cl3(MeCN)]with Na(O2CPh) yields the T-shaped cluster [V3(O)Cl3(O2CPh)2(bipy)2(OEt)2], magnetic studies of which show strong intramolecular antiferromagnetic coupling giving a well isolated S = 1 ground state. Solvothermal treatment of 1 with triols yields a series of polymetallic clusters [V4Cl6(thme)2(bipy)3], [V3Cl4(Hcht)2(bipy)2]Cl and [V8(OH)2Cl4(cht)4(O2CPh)6(bipy)2], structurally related to previously reported {M4} centred triangles. Magnetic studies of this series reveal very weak intramolecular antiferromagnetic exchange and very strong local zero-field splitting effects.