Silicon-carbon bridged bis(fluorenyl) and bis(octahydrofluorenyl) ansa-zirconocenes: synthesis, characterization and ethylene polymerization catalysis

The synthesis and characterization of two new silicon-carbon bridged ansa-bis(fluorenyl) and ansa-bis(octahydrofluorenyl) zirconocene complexes, (Flu-CH(2)-SiMe(2)-Flu)ZrCl(2) (3) and (FluH(8)-CH(2)-SiMe(2)-FluH(8))ZrCl(2) (4) is reported. Complex 3, in combination with methylaluminoxane (MAO), forms an active catalyst system for homogeneous polymerization of ethylene. The molecular structure of 4 reveals a large Centroid-Zr-Centroid angle (131.9 degrees) and an unusually small Cl-Zr-Cl angle (93.2 degrees). The Zr-C bond distances range from 2.48 to 2.64 Angstrom. (C) 1997 Elsevier Science S.A.