ansa-Zirconocene Complexes with Modified Benzindenyl Ligands: Syntheses, Crystal Structure, and Properties as Propene Polymerization Catalysts1,2

As modifications of the effective catalyst precursor [dimethylsilanediylbis(benz[ e ]indenyl)]zirconium dichloride, the ansa -zirconocene complexes Me 2 Si(cyclopenta[ c ]phenanthryl) 2 ZrCl 2, Me 2 Si(cyclopenta[ l ]phenanthryl) 2 ZrCl 2, Me 2 Si(2-methylcyclopenta[ l ]phenanthryl) 2 ZrCl 2, and Me 2 Si(2-methyltetrahydrobenz[ e ]indenyl) 2 ZrCl 2 have been synthesized. When activated by methylaluminoxane (MAO), these complexes give highly active catalysts for the polymerization of propene to polymers with high isotacticities and molecular weights.