ω-Phenylalkyl-substituted zirconocene dichloride complexes as catalyst precursors for homogeneous ethylene polymerization

The reaction of ω-phenyl-1-bromoalkanes with cyclopentadienyl sodium, indenyl lithium or fluorenyl lithium forms ω-phenylalkyl-substituted ligand precursors in high yields. The corresponding anions react with zirconium tetrachloride to give ω-phenylalkyl-substituted zirconocene dichloride complexes. After activation with methylaluminoxane, these complexes are highly active catalysts for homogeneous ethylene polymerization. The nature of the ω-phenyl substituents determines the polymerization activities of the catalysts to a large extent. The polymerization results of 28 new complexes are compared.