Olefin polymerization behavior of titanium(IV) alkoxo complexes with fluorinated diolate ligands: The impact of the chelate ring size and the nature of organoaluminum compounds

Abstract

Titanium(IV) coordination compounds are effectively used as precatalysts for ethylene polymerization and copolymerization with other olefins. New titanium(IV) complexes 3b–d with ligands containing two diphenylcarbinol fragments linked by the perfluorinated hydrocarbon units –CF2– or –C2F4– were synthesized. The structures of complexes 3b and 3d were determined by X‐ray diffraction. Titanium atoms in 3b have a distorted trigonal‐bipyramidal coordination environment while spiro‐complex 3d is characterized by tetrahedral molecular geometry. The catalytic behavior of complexes activated by mixtures of Bu2Mg and alkylaluminium chlorides from among Me2AlCl, Et2AlCl, EtAlCl2, and Et3Al2Cl3 were studied. The resulting catalytic systems catalyze ethylene polymerization to afford ultra‐high molecular weight polyethylene, suitable for modern processing methods, and the solvent‐free solid state formation of super high‐strength (1.37–2.75 GPa) and high‐modulus (up to 138 GPa) oriented film tapes. The same catalytic systems catalyze ethylene copolymerization with 1‐hexene to afford high molecular weight semicrystalline elastomeric polymers containing up to 20% of comonomer units.