NEW INTERMEDIATES FOR THE SYNTHESIS OF OLEFIN POLYMERIZATION CATALYSTS - THE COMPLEXES [M2(MU-CL)2CL4(THF)4] (M = TI OR V, THF = TETRAHYDROFURAN) - CRYSTAL-STRUCTURES AND PROPERTIES

The dimeric titanium(III) and vanadium(III) complexes [M2(mu-Cl)2Cl4(t hf)4] (M = Ti 1 or V 2, thf = tetrahydrofuran) have been prepared by r ecrystallization of (MCl3(thf)3] from dichloromethane. In the dimers, composed of slightly distorted edge-sharing octahedra, the metal atoms separated by Ti ... Ti and V ... V distances of 3.711 (3) and 3.619(1 ) angstrom, respectively, are surrounded by two terminal Cl atoms, two oxygen atoms of thf molecules and are linked by two bridging Cl atoms . The geometry around the titanium atoms differs from that around vana dium because the thf molecules and the terminal chlorine atoms are dif ferently located with respect to the bridging chlorine atoms of the M2 (mu-Cl)2 unit. High catalytic activity was found for ethylene polymeri zation by 1.