Ji Gang, Chen Zhou, Wang Xiao-Yan, Ning Xiao-Shan, Xu Chong-Jie, Zhang Xing-Min, Tao Wen-Jie, Li Jun-Fang, Gao Yanshan, Shen Qi, Sun Xiu-Li, Wang Hao-Yang, Zhao Jun-Bo, Zhang Bo, Guo Yin-Long, Zhao Yanan, Sun Jiajie, Luo Yi, Tang Yong
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China.
School of Chemistry and Chemical Engineering, Soochow University, Suzhou, China.
Nat Commun. 2021 Nov 1;12(1):6283. doi: 10.1038/s41467-021-26470-x.
Ethylene/polar monomer coordination copolymerization offers an attractive way of making functionalized polyolefins. However, ethylene copolymerization with industrially relevant short chain length alkenoic acid remain a big challenge. Here we report the efficient direct copolymerization of ethylene with vinyl acetic acid by tetranuclear nickel complexes. The protic monomer can be extended to acrylic acid, allylacetic acid, ω-alkenoic acid, allyl alcohol, and homoallyl alcohol. Based on X-ray analysis of precatalysts, control experiments, solvent-assisted electrospray ionization-mass spectrometry detection of key catalytic intermediates, and density functional theory studies, we propose a possible mechanistic scenario that involves a distinctive vinyl acetic acid enchainment enabled by Ni···Ni synergistic effects. Inspired by the mechanistic insights, binuclear nickel catalysts are designed and proved much more efficient for the copolymerization of ethylene with vinyl acetic acid or acrylic acid, achieving the highest turnover frequencies so far for both ethylene and polar monomers simultaneously.
乙烯/极性单体配位共聚为制备功能化聚烯烃提供了一种有吸引力的方法。然而，乙烯与具有工业相关性的短链长度链烯酸的共聚仍然是一个巨大的挑战。在此，我们报道了通过四核镍配合物实现乙烯与乙烯基乙酸的高效直接共聚。质子单体可以扩展到丙烯酸、烯丙基乙酸、ω-链烯酸、烯丙醇和高烯丙醇。基于前催化剂的X射线分析、对照实验、关键催化中间体的溶剂辅助电喷雾电离质谱检测以及密度泛函理论研究，我们提出了一种可能的机理，该机理涉及由Ni···Ni协同效应实现的独特的乙烯基乙酸链增长。受机理见解的启发，设计了双核镍催化剂，并证明其在乙烯与乙烯基乙酸或丙烯酸的共聚中效率更高，同时实现了乙烯和极性单体迄今为止最高的转化频率。
