Synthesis, characterization and ethylene polymerization of 1-(2,6-dimethy1-4-fluorenylphenylimino)-2-aryliminoacenaphthylnickel bromides

摘要

A series of 1-(2,6-dimethy1-4-fluorenylphenylimino)-2-aryliminoacenaphthylene compounds (aryl = 2,6-di(Me)Ph (L1), 2,6-di(Et)Ph (L2), 2,6-di(i-Pr)Ph (13), 2,4,6-tri(Me)Ph (L4), 2,6-di(Et)-4-MePh (1,5)) was prepared and used to form their corresponding dibro-monickel complexes (D1-D5). Both L1-L5 and D1-D5 were fully characterized by FT-IR and elemental analysis as well as NMR measurements in the case of ligands L1-L5. The molecular structure of the representative complex D5 was confirmed by single crystal X-ray diffraction revealing a distorted trigonal bipyramidal geometry around the nickel center. On activation with either ethylaluminium sesquichloride (Et3Al2Cl3, EASC) or methylaluminoxane (MAO), all nickel complexes exhibited high activities up to 9.82 x 10(6) g of PE (mol of Ni)(-1) h(-1) for ethylene polymerization. In comparison with the polyethylenes obtained with related Ni pre-catalysts, the polyethylenes obtained in this work possessed relatively higher molecular weights and lower levels of branching, highlighting the significant influence of the remote fluorenyl substituent. (C) 2016 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.