Synthesis and structural characterization of novel three carbon atom bridged ansa-bis(indenyl)zirconocene complexes: Applications in ethylene polymerization

The ansa indenyl ligand precursors CH2CH2CH2(C9H6R)2 (R = Me (7), Et (8), Pr (9)) have been prepared by the reaction of the corresponding lithium indene, Li(C9H6R-1) (R = Me (4), Et (5), Pr (6)), with 1,3-dibromopropane. Compounds 7–9 were converted, by the reaction with butyllithium, to the dilithium compounds, Li2{CH2CH2CH2(C9H5R-3)2} (R = Me (10), Et (11), Pr (12)). The three carbon atom bridge ansa-bis(indenyl)zirconium complexes, [Zr{CH2CH2CH2(η5-C9H5R-3)2}Cl2] (R = Me (13), Et (14) Pr (15)) were synthesized from the reaction of 10–12 with zirconium tetrachloride. Compounds 13–15 have been tested as homogeneous catalysts in the polymerization of ethylene. The molecular structures of 14 and 15 have been determined by single-crystal X-ray diffraction studies.