Catalytic oxidations by vanadium complexes

Vanadium haloperoxidases catalyse the oxidation of halides leading to halogenation of substrates or, in the absence of suitable substrates, to oxidation of hydrogen peroxide into singlet oxygen and water. Furthermore, V-haloperoxidases are capable to give enantioselective sulfoxidation under the, appropriate conditions. The most interesting model compounds that have been synthesised and studied as bromination catalysts, and catalysts for, i.e. epoxidation, hydroxylation, sulfoxidation and alcohol oxidation are discussed in this paper. Our recent work includes the investigation on a vanadium complex as potential catalyst for bromination reactions, attempts to synthesise a novel structural model for the active site of V-peroxidase using a tripodal ligand, and the syntheses and characterisation of four new vanadium complexes containing tridentate ligands. The latter compounds have been studied as oxidation catalysts using cinnamyl alcohol as substrate. (C) 2002 Elsevier Science B.V. All rights reserved.