Synthesis, Structures, and Polymerization Catalytic Properties of Doubly Bridged Bis(cyclopentadienyl) Dinuclear (μ-Oxo)titanium Complexes

The doubly bridged dinuclear (μ-oxo)titanium complex (Me2C)(Me2Si)(C5H3)2(μ-O)(CpTiCl)2 (1) was synthesized by the reaction of the lithium compound of the doubly bridged bis(cyclopentadienyl) ligand with (CpTiCl2)2O. Treatment of 1 with concentrated HCl or HBr gave the corresponding Cp-decoordinated products (Me2C)(Me2Si)(C5H3)2[CpTiX(μ-O)TiX2] (X = Cl (2), Br (3)). All these titanium complexes were characterized by 1H NMR, 13C NMR, MS spectra, and elemental analysis. The crystal structures of (CpTiCl2)2O, 1, and 3 were determined by X-ray diffraction. Their catalytic properties for ethylene polymerization were also studied in the presence of MAO.