Imino-indolate half-titanocene chlorides: Synthesis and their ethylene (co-)polymerization

A series of imino-indolate half-titanocene chlorides, Cp′Ti(L)Cl2 (C1–C7: Cp′ = C5H5, MeC5H4, C5Me5, L = imino-indolate ligand), were synthesized by the reaction of Cp′TiCl3 with sodium imino-indolates. All complexes were characterized by elemental analysis, 1H and 13C NMR spectroscopy. Moreover, the molecular structures of two representative complexes C4 and C6 were confirmed by single crystal X-ray diffraction analysis. On activation with methylaluminoxane (MAO), these complexes showed good catalytic activities for ethylene polymerization (up to 7.68 × 106 g/mol(Ti)·h) and ethylene/1-hexene copolymerization (up to 8.32 × 106 g/mol(Ti)·h), producing polyolefins with high molecular weights (for polyethylene up to 1808 kg/mol, and for poly(ethylen-co-1-hexene) up to 3290 kg/mol). Half-titanocenes containing ligands with alkyl substituents showed higher catalytic activities, whereas the half-titanocenes bearing methyl substituents on the cyclopentadienyl groups showed lower productivities, but produced polymers with higher molecular weights. Moreover, the copolymerization of ethylene and methyl 10-undecenoate was demonstrated using the C1/MAO catalytic system. The functionalized polyolefins obtained contained about 1 mol % of methyl 10-undecenoate units and were fully characterized by several techniques such as FT-IR, 1H NMR, 13C NMR, DSC, TGA and GPC analyses. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 357–372, 2009