Bridged indenylidene-cyclopentadienylidene complexes of type (C9H5CH2Ph-X-C5H4)MCl2 (X = CMe2, SiMe2; M = Zr, Hf) as metallocene catalysts for ethylene polymerization.: Molecular structure of (C9H5CH2Ph-CMe2-C5H4)MCl2 (M = Zr, Hf)

The synthesis and NMR spectroscopic characterization of new ansa metallocene dichloride complexes of the type (C9H5CH2Ph-X-C5H4)ZrCl2 (X = CMe2, SiMe2; M = Zr, Hf) are reported. These ansa metallocene complexes and the unbridged derivative (C9H6CH2Ph)(C5H5)ZrCl2 can be activated with methyl aluminoxane (MAO) to polymerize ethylene. The benzyl substituent in the 3-position of the indenyl ligand and the nature of the bridge X have an influence on the activity of these catalysts. These parameters also determine the molecular weights of the polymers. Two ansa metallocene complexes (4, 5) were also characterized by X-ray diffraction.