Synthesis, characterization, and ethylene polymerization behavior of [(RR′-admpzp)2Ti(OPri)2] complexes (RR′-admpzp = 1-dialkylamino-3-(3,5-dimethyl-pyrazol-1-yl)-propan-2-olate)

[(RR′-admpzp)2Ti(OPri)2] complexes (2a–c), synthesized from reaction of Ti(OPri)3Cl (0.5 equiv) with 1-dialkylamino-3-(3,5-dimethyl-pyrazol-1-yl)-propan-2-ol compounds in the presence of triethylamine (0.5 equiv), are pseudo-octahedral with each RR′-admpzp ligand κ2-O,N(pyrazolyl) coordinated to the titanium center. In solution, 2a–c adopt isomeric structures that are in dynamic equilibrium. At 23 °C, 2a–c/1000 MAO catalyst systems furnished high molecular weight polymers with narrow molecular weight distributions (Mw/Mn = 2.7–2.8). At 100 °C, 2a–c/MAO catalyst systems exhibited increased polymerization activity and 2c/1000 MAO system furnished high molecular weight polyethylene with a molecular weight distribution (Mw/Mn = 2.1) that is close to that found for single-site catalysts.