New group 4 half sandwich complexes containing triethanolamine ligand for polyethylene

(η5-C5Me5)M(TEA) (M = Ti, 1; Zr, 2; Hf, 3; TEA = triethanolateamine) was prepared by the reaction of (η5-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 (Mv) and melting temperature (Tm) of all the resulting polyethylene obtained by 2/MAO show the range of Mv = 91,200–356,200 and Tm = 137.0–141.9 °C, respectively; however, 1/MAO and 3/MAO gave polyethylenes with lower molecular weight (Mv = 6800–78,700) and lower melting temperature (Tm = 125.9–136.7 °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.

Graphical abstractThe half-sandwich group 4 complexes have been synthesized and utilized as catalysts for polyethylene. These catalysts at various solution polymerization temperatures and [Al]/[M] molar ratio in toluene and their catalytic capabilility were investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide