Syntheses, Characterization, and Ethylene Polymerization of Half-Sandwich Zirconium Complexes with Tridentate Imino−Quinolinol Ligands

A series of half-sandwich zirconium complexes with imino-quinolinol ligands have been synthesized and characterized. The catalytic behaviors of these complexes toward ethylene polymerization were investigated in the presence of methylaluminoxane (MAO) as a cocatalyst. The catalytic behaviors were highly affected by the substituent in both cyclopentadienyl and imino−quinolinol ligands. The Cp analogue complexes CpZr[ONNR]Cl2 (1a−e) exhibited high activities up to 1.34 × 107 g of PE (mol of Zr)−1 h−1, whereas the Cp* analogue complexes Cp*Zr[ONNR]Cl2 (2a−e) also showed moderate activities for ethylene polymerization.