Synthesis and ROMP activity of aminophenol-substituted tungsten(VI) and molybdenum(VI) complexes

Tungsten(VI) and molybdenum(VI) complexes [MO(L(1))Cl(2)] and [M(X)(L(2))Cl(3)] (X = O, NPh) with tridentate aminobis(phenolate) ligand L(1) = methylamino-N,N-bis(2-methylene-4,6-dimethylphenolate) and bidentate aminophenolate ligand L(2) = 2,4-di-tert-butyl-6-((dimethylamino) methyl) phenolate) were prepared and characterised. These complexes are principally stable in open atmosphere under ambient conditions. When activated with Et(2)AlCl, they exhibited high activity in ring-opening metathesis polymerisation (ROMP) of 2-norbornene (NBE) and its derivatives. Especially complexes [M(NPh)(L(2))Cl(3)], which are easily available from corresponding metal oxides MO(3) by a simple three-step synthesis, were found very efficient ROMP catalysts for NBE (M = Mo, W) and 2-norbornen-5-yl acetate (M = Mo). (C) 2008 Elsevier B.V. All rights reserved.