Synthesis, structures and polymerization catalytic properties of germyl-bridged bis(cyclopentadienyl) metallocenes

The ansa-metallocene complexes Me2Ge(η5-C5Me4)2MCl2 [M=Ti (1), Zr (2)], Me2Ge(η5-C5H3Bu-t)2ZrCl2 (3) and Me2Ge(η5-C5H4)(η5-C5H3R)ZrCl2 [R=Me (4), t-Bu (5)] were prepared by the reaction of the corresponding ligands with n-BuLi and MCl4·2THF, respectively. The molecular structures of 1 and 2 have been determined by the X-ray diffraction method. Complexes 2–5 in combination with MAO were studied as catalysts for ethylene polymerization and all the germyl-bridged zirconocene catalysts show high activities at relative high temperatures. This indicates that the germyl-bridged zirconocene systems show thermally stable catalyst systems for polymerization of ethylene.