Mononuclear tungsten(VI) complexes with bis(phenolato) ligands: syntheses, characterisations and activity in ROMP reaction

: Lehtonen A, Sillanpaa R

Publisher: PERGAMON-ELSEVIER SCIENCE LTD

: 2002

: Polyhedron

: POLYHEDRON

: 21

: 9-10

: 1017

: 1022

: 6

: 0277-5387

DOI: https://doi.org/10.1016/S0277-5387(02)00897-5

The reaction of bulky ligand precursor 2,2-methylenebis(4-methyl-6-tert-butylphenol) (H(2)mbp) or 2,2'-ethylidenebis(4,6-di-tertbutylphenol) (H(2)ebp) with trisdiolatotungsten(VI) complex [W(eg)(3)] 1 (eg = ethanediolate dianion) provides heteroleptic complexes [W(mbp)(eg)(2)] 2 or [W(ebp)(eg)(2)] 3, respectively. Sterically less hindered 2,2'-dihydroxy-1,1'-dinaphtylmethane (H(2)dinap) forms heteroleptic disubstituted complex [W(dinap)(2)(eg)] 4. The X-ray crystal structure determinations confirmed that the isolated compounds are made of monomeric tris(diolato)tungsten(VI) molecules in which the central tungsten atom is bonded to six oxygen atoms forming a distorted octahedral coordination sphere around the metal ion. Complexes 2 and 3 catalyse the ring opening metathesis reaction of norbornene when activated by Et2AlCl. (C) 2002 Elsevier Science Ltd. All rights reserved.