Novel diphenyl thioether-bridged binuclear metallocenes of Ti and Zr for synthesis of polyethylene with broad molecular weight distribution.

Two diphenyl thioether-bridged binuclear metallocenes of Ti and Zr, [(CH)ClMCHCH( p-CH)]S [M = Ti (1) and Zr (2)], have been synthesized by treating the dilithium salts of the corresponding ligand [(CHCH( p-CH)]S with two equivalents of CHTiCl and CHZrCl(DME), respectively, in toluene at 0°C. Both new complexes have been characterized by H-NMR spectroscopy and elemental analysis. Homogeneous ethylene polymerization using both complexes was performed in the presence of methylaluminoxane (MAO). The influences of molar ratio of [MAO]/[Cat], concentration of the catalysts, time, and temperature have been studied systematically. The catalytic activity of is higher than that of the corresponding oxygen-bridged catalyst [(CH)ClTiCHCH( p-CH)]O. The catalytic activity of is at least two times higher than that of under any tested polymerization conditions. The melting points of polyethylene (PE) produced by and are higher than 130°C, indicating a highly linear and highly crystalline PE. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]