Positional Electronic Effects in Iminopyridine-N-oxide Nickel Catalyzed Ethylene Polymerization

• 作者: Mingjun Chi Ao Chen Wenmin Pang Chen Tan Changle Chen
• 来源期刊: 中国化学（英文版）
• 年，卷（期）: 2021,（6）
• 所属期刊栏目: Comprehensive Reports
• 页码范围: 1683-1689
• 页数: 7页
• 语种: 英文
• DOI: 10.1002/cjoc.202000712

摘要

Main observation and conclusion A series of dibenzhydryl-based iminopyridine-N-oxide ligands bearing a range of electron-donating or-withdrawing substituents(OMe,H,and NO2)and corresponding nickel pre-catalysts are prepared and characterized.The substituents are installed at different positions on the ligand structure,including 4-position of the pyridine-N-oxide moiety(position X)and 4-position of the aniline moiety(position Y).These nickel pre-catalysts are highly active in ethylene polymerization with the addition of very little amount of alumi-num cocatalysts,leading to the formation of polyethylenes with molecular weights of well above one million.Electron-donating sub-stituents make the catalysts sensitive to polymerization temperature.In contrast,the catalysts bearing electron-withdrawing NO2 substituents show relatively steady performances at different temperatures.Most importantly,we demonstrate that different sub-stituents and different positions both play important roles in determining the properties of nickel catalysts.This provides an alterna-tive strategy for the future design of high-performance polymerization catalyst.