Dinuclear Transition Metal Complexes Consisting of an α-Diimine Complex Unit and a Half Sandwich Complex Unit as Dual Site Catalysts for the Polymerization of Ethylene

Dinuclear complexes consisting of an α-diimine complex unit with different ortho substituents at the aryl rings and a half sandwich complex unit were prepared, activated with methylaluminoxane (MAO) and tested for the polymerization of ethylene. The dinuclear catalysts bearing zirconium centers showed higher ethylene polymerization activities than the analogous titanium catalysts. Among the dinuclear catalysts with the same metal centers, the bulkier ortho substituents at the aryl moiety gave lower polymerization activities. The GPC spectra of the polyethylenes produced with the dinuclear catalysts displayed bimodal molecular weight distributions due to different active sites.