Living polymerization of ethylene with titanium complexes having two indolide-imine chelate ligands

Four titanium complexes bearing two unsymmetrical indolide-imine chelate ligands (named 11 Catalysts) were synthesized and investigated for their potential as ethylene polymerization catalysts using methylaluminoxane (MAO) as a cocatalyst. Three 11 Catalysts, with R = phenyl, 2,6-difluorophenyl, or 2,4,6-trifluorophenyl as an aryl group on the imine nitrogen, promoted room-temperature living ethylene polymerization to produce polyethylenes having extremely narrow molecular weight distributions (M-w/M-n: 1.11 similar to 1.14), displaying very high activities (TOF; 31 similar to 171 min(-1) (.) atm(-1)). The other II Catalyst, R-pentafluorophenyl, exhibited a very high activity of 1140 kg-PE/mol-cat (.) h (TOF; 677 min(-1) (.) atm(-1)), which is one of the highest activities for a titanium complex having no Cp ligands. It exhibited a high molecular weight value, M-w 323000, at room temperature.