Bisdiolatotungsten(VI) phenoxide-based catalytic systems for ring opening metathesis polymerization

Bisdiolatotungsten(VI) complexes of the type [W(diol)2(phe)2] and [W(diol)2(biphe)] (diol =aliphatic diolate dianion, phe = substituted phenolate, biphe = substituted biphenolate) were studied as catalyst precursors for ring opening metathesis polymerization of norbornene and dicyclopentadiene. These compounds form active catalysts when activated by Et2AlCl. Syntheses of two new precursor complexes, [W(eg)2(tBu2phe)2] and [W(eg)2(tBu4biphe)] along with the crystal structure of latter are also described.