Olefin Polymerization Catalyzed by Titanium−Tungsten Heterobimetallic Dinitrogen Complexes¹

A new family of highly active olefin polymerization catalysts based on titanium−tungsten heterobimetallic dinitrogen complexes, [Cp‘TiCl₂(μ-N₂)WCl(L)₄] (1; L = PMe₂Ph, 1/2 R₂PCH₂CH₂PR₂; R = Et, Ph), has been developed, in which the tungsten dinitrogen fragment acts as a novel metallonitrogen ligand to the catalytically active titanium center. Alkylation of 1d (Cp‘ = C₅Me₅, L = 1/2 Et₂PCH₂CH₂PEt₂) with MeLi gave di- and trimethyl derivatives 2d and 3d, which were structurally characterized.