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

Abstract

The ansa half-sandwich complex [η 5:η 1-C 5H 4-C(CH 3) 2-2-C 6H 4O]TiCl 2 ( 1) has been prepared using two different ways, a ‘one-pot’ synthesis and a synthesis via thermolysis of the Ti trichloride precursor [η 5-C 5H 4-C(CH 3) 2-2-C 6H 4OCH 3]TiCl 3 ( 3). When activated with methylaluminoxane ( 4) or the cocatalyst system triisobutyl aluminum/[Me 2PhNH] +[B(C 6F 5) 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 Me 2Si[IndH 4] 2ZrCl 2/ 4.