Soshnikov Igor E, Bryliakov Konstantin P, Antonov Artem A, Sun Wen-Hua, Talsi Evgenii P
Boreskov Institute of Catalysis, 630090, Novosibirsk, Pr. Lavrentieva, 5, Russian Federation.
Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China and CAS Research/Education Center for Excellence in Molecular Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
Dalton Trans. 2019 Jun 21;48(23):7974-7984. doi: 10.1039/c9dt01297d. Epub 2019 May 9.
α-Diimine and related complexes of late transition metals such as palladium and nickel have been attracting continuing interest as single-site catalysts of ethylene homopolymerization to branched polyolefins, having challenging mechanical properties. The state-of-the art catalysts demonstrate promising catalytic activities, and enhanced thermal stabilities, affording polyethylenes with a variable degree of branching and, in addition, are able to incorporate polar co-monomers into polyethylene structures. At the same time, fundamental understanding of the structure-reactivity relationships of such catalysts mostly remains at the phenomenological level, due to the lack of experimental data on the solution structures of intermediates that drive the polymerization process. In this perspective, we discuss recent advances of α-diimine nickel based catalysts of ethylene polymerization, focusing on the relationships between the catalyst structures on the one hand, and their thermal stabilities and properties of the resulting polyethylene, on the other hand. In addition, some intriguing novel mechanistic findings of these catalyst systems are presented.
α-二亚胺及钯和镍等后过渡金属的相关配合物作为乙烯均聚合成具有挑战性机械性能的支化聚烯烃的单中心催化剂，一直备受关注。目前最先进的催化剂表现出有前景的催化活性和增强的热稳定性，能提供具有不同支化度的聚乙烯，此外，还能够将极性共聚单体引入聚乙烯结构中。与此同时，由于缺乏驱动聚合过程的中间体溶液结构的实验数据，对此类催化剂结构与反应活性关系的基本理解大多仍停留在现象学层面。从这个角度出发，我们讨论了α-二亚胺镍基乙烯聚合催化剂的最新进展，重点关注一方面催化剂结构与另一方面其热稳定性及所得聚乙烯性能之间的关系。此外，还介绍了这些催化剂体系一些有趣的新机理发现。
