Synthesis, characterization and polymerization properties of bridged halfsandwich complexes of titanium, Zirconium and Hafnium -: The molecular structure of [C13H8-SiMe2-NtBu]ZrCl2

The synthesis of new ansa halfsandwich complexes of the type [Cp-not equal -SiMe2-N'Bu]MCl2 (Cp-not equal = C13H8, C9H6, C5H4, C5H3'Bu; M = Zr, Hf) as catalyst precursors for the polymerization of ethylene is described. The complexes were characterized by H-1-, C-13-, Si-29-, N-15- and N-14-NMR spectroscopy. From [C13H8-SiMe2-N'Bu]ZrCl2 an X-ray structure was obtained. The activities of the catalysts and the properties of the polymers were investigated. The influence of the catalyst structure on the polymerization behaviour is discussed.