Synthesis and application in high-pressure polymerization of a titanium complex with a linked cyclopentadienyl-phenoxide ligand

The ansa half-sandwich complex [η5:η1-C5H4-C(CH3)2-2-C6H4O]TiCl2 (1) has been prepared using two different ways, a ‘one-pot’ synthesis and a synthesis via thermolysis of the Ti trichloride precursor [η5-C5H4-C(CH3)2-2-C6H4OCH3]TiCl3 (3). When activated with methylaluminoxane (4) or the cocatalyst system triisobutyl aluminum/[Me2PhNH]+[B(C6F5)4]− (5), complex 1 could be used as a catalyst in high-pressure, high-temperature polymerization. The productivity of the catalyst system 1/4 in high-pressure polymerization of ethene is 400 t polymer mol−1 Ti, while the productivity of catalyst system 1/5 is only 6 t polymer mol−1 Ti. In ethene/1-hexene copolymerizations productivity and molecular weights decrease with increasing 1-hexene in the feed. The polymerization results were discussed and compared to results of high-pressure polymerization with the catalyst system Me2Si[IndH4]2ZrCl2/4.