New compounds of tetradentate Schiff bases with vanadium(IV) and vanadium(V)†

Abstract

A new range of potentially tetradentate proligands, H₂L, derived from aromatic aldehydes and ketones and aliphatic diamines has been prepared. Their vanadyl(IV) and vanadyl(V) complexes [VO(L)] and [VO(L)]⁺, and also some adducts [VO(L)→VO(L)]⁺, have been synthesized. The structures of four selected complexes have been determined and it is shown that these must be a result of both steric and electronic factors that make prediction of conformation and stacking difficult. The adducts [VO(L)→VO(L)]⁺ have structures that persist in solution in dichloromethane, where they can undergo redox chemistry, but they apparently dissociate into their component complexes in the donor solvent acetonitrile.