Zirconium dichloride complexes with bulky ω-9-methylfluorenylalkyl substituted indenyl ligands as catalysts for homogeneous ethylene polymerization

Abstract

The synthesis and characterization of four new zirconium complexes with bulky ω-9-methylfluorenylalkyl substituted indenyl ligands are reported. After activation with methylaluminoxane (MAO) they can be applied as highly active catalysts for ethylene polymerization. The activities of the catalysts depend on the length of the CH2-spacer chain between the indenyl and the 9-methylfluorenyl moieties. The best results were obtained with four CH2 groups. This speaks for a comparatively free catalyst cation allowing easy coordination of the monomer to the active site and unhindered growth of the polymer chain.