Synthesis, structure and polymerization catalytic properties of doubly bridged bis(cyclopentadienyl) dinuclear titanium and zirconium complexes

Abstract

A series of doubly bridged dinuclear titanium and zirconium complexes (Me 2C)(Me 2E)(C 5H 3) 2(Cp′MCl 2) 2 [E=Si, Cp′=C 5H 5, M=Ti ( 1), Zr ( 2); E=Ge, Cp′=C 5H 5, M=Ti ( 3), Zr ( 4); Cp′=C 5Me 4H, M=Zr, E=Si ( 5), Ge ( 6)] and (Me 2SiOSiMe 2) 2(C 5H 3) 2(Cp′MCl 2) 2 [Cp′=C 5H 5, M=Ti ( 7), Zr ( 8); Cp′=C 5Me 4H, M=Zr ( 9)] were synthesized by the reaction of the lithium compounds of the corresponding doubly bridged cyclopentadienyl ligands with CpTiCl 3, CpZrCl 3(THF) 2 or C 5Me 4HZrCl 3, respectively. These complexes were characterized by 1H-NMR, MS and elemental analysis. The crystal structure of 4 was determined by the X-ray diffraction. Their catalytic properties for ethylene polymerization were also studied in the presence of MAO.