Ethylene polymerization by novel phenylenedimethylene bridged homobinuclear titanocene/MAO systems

Reaction of (o, m, p) disodium(phenylenedimethylene)dicyclopentadienide C6H4(CH2C5H4Na)2 with 2 equiv of (MeCp)TiCl3 yields the phenylenedimethylene bridged binuclear titanocenes complexes [(MeC5H4)TiCl2](C5H4CH2C6H4CH2C5H4)[(MeC5H4)TiCl2] (3, 4, 5) in high yield, which were characterized by 1H NMR and elemental analysis. They were used successfully as efficient catalysts for ethylene polymerization in the presence of methylaluminoxane (MAO). The catalytic activities of 4 and 5 are somewhat higher than that of 3 and the molecular weight distributions (MWD = 4.8-6.2) of the polymers generated from the bimetallic catalytic systems are obviously higher than that obtained by conventional Cp2TiCl2.