Asymmetric dinuclear ansa zirconocene complexes with methyl and phenyl substituted bridging silicon atoms as dual site catalysts for the polymerization of ethylene

Sixteen asymmetric dinuclear ansa zirconocene complexes bearing cyclopentadienyl, indenyl or fluorenyl ligands and their ligand precursors have been synthesized and characterized by NMR spectroscopy. After activation with methylalumoxane (MAO), the complexes behave like dual site catalysts and produce polyethylenes with bimodal or broad molecular weight distributions in homogeneous and heterogeneous media.