Synthesis of titanium(IV) complexes that contain the Bis(silylamide) ligand of the type [1,8-C10H6(NR)2]2−, and alkene polymerization catalyzed by [1,8-C10H6(NR)2]TiCl2-cocatalyst system
摘要:
[1,8-C10H6(NR)(2)]TiCl2 (3; R = SiMe3, (SiBuMe2)-Bu-i, (SiPr3)-Pr-i) complexes have been prepared from dilithio salts [1,8-C10H6(NR)(2)]Li-2 (2) and TiCl4 in diethyl ether in moderate yields (60-63%), These complexes showed significant catalytic activities for ethylene polymerization and for ethylene/1-hexene copolymerization in the presence of methylaluminoxane (MAO), methyl isobutyl aluminoxane (MMAO), (AlBu3)-Bu-i- or AlEt3-Ph3CB(C6F5)(4) as a cocatalyst, The catalytic activities performed in heptane (cocatalyst MMAO) were higher than those carried out in toluene (cocatalyst MAO): 709 kg-PE/mol-Ti . h could be attained for ethylene polymerization by using [1,8-C10H6((NSiBuMe2)-Bu-i)(2)]TiCl2-MMAO catalyst system. (C) 1998 Elsevier Science B.V.