Shaobo Zai, Haiyang Gao, Zengfang Huang
Feb 22, 2012
Citations
0
Influential Citations
65
Citations
Journal
ACS Catalysis
Abstract
A series of pyridine-amine nickel complexes with various substituents were synthesized and used to evaluate substituent effects of catalyst precursors on the reactivity of ethylene polymerization. Substituent effects, including the steric effect of the pyridine moiety, steric effect of the bridge carbon, and steric and electronic effects of the amine moiety, were investigated systematically. Introduction of bulky aryls onto the pyridine moiety on amine pyridine nickel leads to a significant decrease in the activity and molecular weight of polyethylene, whereas an increase in bulk of substituents on the bridge carbon causes an increase in the polymerization activity and molecular weight of polyethylene. For the amine moiety, increasing the steric hindrance results in decreasing activity and affords a higher molecular weight polyethylene with a narrower polydispersity, and introduction of an electron-donating group on the amine moiety leads to formation of a high molecular weight polyethylene with enhanced ...