Synthesis and physico-chemical characterization of [Hf(NEt2)2Cl2(DME)] and its use as catalyst for ethylene polymerization

The new solid-state complex {[Hf(NEt2)2Cl2(DME)] (DME = 1,2-dimethoxyethane)}, intermediate in the synthesis of the new bis-diethylamide bis-isopropoxy hafnium (IV) complex [Hf(NEt2)2(OiPr)2], has been synthesized, isolated and characterized by NMR spectroscopy and X-ray diffraction. The crystal structure showed the metal to be hexa-coordinated with a distorted octahedral geometry. Catalytic tests for the polymerization of ethylene have been carried out using this intermediate with [(NHMe2Ph)B(C6F5)4] as cocatalyst. The obtained polymer had a high molecular weight and a high melting point, characteristic of a high density polyethylene (HDPE).