Synthesis and characterisation of neutral tris(bidentate) vanadium(V) complexes containing N3S23– and catecholate ligands

The preparation and characterisation of complexes of the type [V(N3S2)Cl2L] (L = 2,2'-bipyridyl, 1; or 1,10-phenanthroline, 2) and [V(N3S2)L(L')] [L' = catecholate (cat) or 3,5-di-tert-butylcatecholate (dtbc)] 3-6 is described. The new complexes have been characterised by microanalyses, V-51 NMR, IR and visible spectroscopy as well as electrochemistry. All the new complexes are air stable as solids. Complexes 3 and 4 have a one-electron reversible couple and an anodic peak, whereas the dtbc complexes 5 and 6 have two one-electron reversible redox couples. The V-51 NMR spectra of 1-6 are characteristic, in particular there is a large downfield shift on replacing cat by dtbc.