165620-75-7Relevant academic research and scientific papers
Large ultra-high molecular weight polyethylene spherical particles produced by AlR3 activated half-sandwich chromium(iii) catalysts
Sun, Mingtai,Xu, Tieqi,Gao, Wei,Liu, Yang,Wu, Qiaolin,Mu, Ying,Ye, Ling
experimental part, p. 10184 - 10194 (2011/12/05)
A series of half-sandwich pentamethylcyclopentadienyl chromium(iii) complexes bearing a salicylaldiminato ligand, Cp*[2-R1-4-R 2-6-(CHNR3)C6H2O]CrCl [R1 = iPr (1, 4), tBu (2, 3, 5), Ad (6); R2 = H (1, 2, 3), tBu (4, 5, 6); R3 = iPr (1, 2, 5, 6), tBu (3, 4)], were synthesized. All complexes were characterized by elemental analyses and the structures of complexes 1-4 and 6 were determined by X-ray diffraction analysis. These complexes adopt a pseudo-octahedral coordination environment with a three-legged piano stool geometry. Upon activation with a small amount of AlR3, complexes 1-6 all catalyze the polymerization of ethylene in a quasi living fashion with good to high catalytic activity under mild conditions and produce ultra-high molecular weight polyethylene as spherical particles with a diameter of 1-6 mm. The catalytic activity of these complexes and the molecular weight of the produced polyethylene can be tuned in a broad range by changing the R1, R 2, and R3 groups as well as the AlR3 cocatalyst. It was found that complex 6 with R1 = Ad, R2 = tBu, and R3 = iPr shows the highest catalytic activity and produces polyethylene with the highest molecular weight. The Royal Society of Chemistry 2011.
