Novel dimethylsilylene isopropylidene doubly bridged metallocenes: Syntheses, identifications, and activities for olefin polymerizations

Novel doubly bridged metallocene complexes (Me2Si)(Me2C)(C5H3)2MCl2 (M = Ti(4), Zr(8)), were synthesized by reactions of the corresponding ligand dilithium salt with MCl4. The structures were determined by X-ray analysis. As was expected, each of them showed the smallest bite-angle (4: 120°; 8: 114°) in the bis(cyclopentadienyl) type of Ti or Zr complexes. Copolymerizations of ethylene/1-octene were carried out using these metallocenes in the presence of cocatalyst. These complexes show high incorporation abilities.