Dioxotungsten(VI) complexes with tetradentate [O,N,N,O] ligands: syntheses, spectral characterisation and catalytic applications

Two new tungsten(VI) complexes of the type WO2(ONNOR) (ONNOR = tetradentate diaminobis(phenolate) ligand) were prepared by the reaction of trisdiolatetungsten(VI) complex W(eg)3 (eg = 1,2-ethanediolate) and diaminobis(phenol)s in the presence of water. Studied complexes catalysed ROMP of norbornene when activated by Et2AlCl. They also catalysed oxotransfer reaction between DMSO and benzoin.