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, [(C 5 H 5 )Cl 2 MC 5 H 4 CH 2 ( p ‐C 6 H 4 )] 2 S [M = Ti (1) and Zr (2)], have been synthesized by treating the dilithium salts of the corresponding ligand [(C 5 H 5 CH 2 ( p ‐C 6 H 4 )] 2 S with two equivalents of C 5 H 5 TiCl 3 and C 5 H 5 ZrCl 3 (DME), respectively, in toluene at 0°C. Both new complexes have been characterized by 1 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 1 is higher than that of the corresponding oxygen‐bridged catalyst [(C 5 H 5 )Cl 2 TiC 5 H 4 CH 2 ( p ‐C 6 H 4 )] 2 O. The catalytic activity of 2 is at least two times higher than that of 1 under any tested polymerization conditions. The melting points of polyethylene (PE) produced by 1 and 2 are higher than 130°C, indicating a highly linear and highly crystalline PE. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011