New group 4 half sandwich complexes containing triethanolamine ligand for polyethylene

Abstract

(eta(5) -C5Me5)M(TEA) (M = Ti, 1; Zr, 2; Hf, 3; TEA = triethanolateamine) was prepared by the reaction of (eta(5)-C5Me5)MCl3 with triethanolamine in the presence of NEt3. The polyethylene catalytic efficiency in terms of activity decreases in the order 1/MAO > 2/MAO >> 3/MAO. In addition, the molecular weight (M-v) and melting temperature (T) of all the resulting polyethylene obtained by 2/MAO show the range of M-v = 91,200-356,200 and T = 137.0-141.9 degrees C, respectively; however, 1/MAO and 3/MAO gave polyethylenes with lower molecular weight (M-v = 6800-78,700) and lower melting temperature (T-m = 125.9-136.7 degrees C). Furthermore, 1/MAO showed significant decrease in the catalytic activity with increasing polymerization temperature though 2/MAO and 3/MAO have no dependence on the polymerization temperature. (c) 2005 Published by Elsevier B.V.