Vanadium chlorides supported by BIAN (BIAN = bis(arylimo)-acenaphthene) ligands: Synthesis, characterization, and catalysis on ethylene polymerization

摘要

Several vanadium chlorides bearing bis(arylimino)-acenaphthene (BIAN) ligands, (2,6-Me2C6H3-BIAN)V (THF)Cl-3 (1), (2,6-Et2C6H3-BIAN)V(THF)Cl-3 (2), (2,6-(Pr2C6H3)-Pr-i-BIAN)V(THF)Cl-3 (3), [3,5-(CF3)(2)C6H3-BIAN] V(THF)Cl-3 (4), [4-OMe-C6H4-BIAN]V(THF)Cl-3 (5), and [2,6-(Ph2CH)(2)-4-OMeC6H2-BIAN]V. (THF)Cl-3 (6) were synthesized by direct reaction of VCl3(THF)(3) with corresponding BIAN ligands. All these complexes were characterized by elemental analyses, and FT-IR spectroscopy. The molecular structures of 1, 2, and 4 were identified by X-ray crystallography, in which the six-coordinated vanadium metal centers were in distorted octahedral geometry with the oxygen atom of the coordinated THF, two nitrogen atoms of the diimine ligand and one chlorine atom in the same plane. When activated with AlEt2Cl these vanadium complexes showed high catalytic activities for ethylene polymerization affording linear polyethylene with high molecular weight. However, when MAO was used as co-catalyst, ultra high molecular-weight polymers were obtained albeit with decreased activity. (C) 2019 Elsevier Ltd. All rights reserved.