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)
作者:Alexey Zazybin、Sean Parkin、Folami T. Ladipo
DOI:10.1016/j.jorganchem.2007.08.040
日期:2007.11
[(RR'-admpzp)(2)Ti(OPri)(2)] complexes (2a-c), synthesized from reaction of Ti(OPri)(3)Cl (0.5 equiv) with 1-dialkylamino-3-(3,5dimethyl- pyrazol-1-yl)-propan-2-ol compounds in the presence of triethylamine (0.5 equiv), are pseudo-octahedral with each RR'admpzp ligand kappa(2)-O,N(pyrazolyl) coordinated to the titanium center. In solution, 2a-c adopt isomeric structures that are in dynamic equilibrium. At 23 degrees C, 2a-c/1000 MAO catalyst systems furnished high molecular weight polymers with narrow molecular weight distributions (M-w/M-n = 2.7-2.8). At 100 degrees 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 (M-w/M-n = 2.1) that is close to that found for single-site catalysts. (C) 2007 Elsevier B.V. All rights reserved.