The incorporation of even a small number of polar functional groups in the polyolefin backbone is sufficient to improve the polyolefin properties. Compared with palladium catalyzed direct copolymerization of olefins with polar vinyl monomers, the development of low-cost nickel-based catalysts is more challenging because of their higher oxophilicity. On the basis of the advantage of reducing the electrophilicity of the nickel center by the installation of strongly electron-donating ligands, we herein report the synthesis of novel bis(N-acylated imidazolin-2-imine) nickel complexes for norbornene polymerization and copolymerization with polar monomers. Moreover, the phenyl substituent on the imidazoline ligand is expected to enhance the tolerance of the nickel catalyst toward polar functional groups, thus allowing the copolymerization of norbornene with commercial methyl acrylate to afford high molecular weight functionalized cyclic olefin copolymers (COCs) with moderate activity and reasonable comonomer content.

中文翻译：

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双（N-酰化咪唑啉-2-亚胺）镍催化的降冰片烯与丙烯酸甲酯的共聚

在聚烯烃主链中甚至引入少量极性官能团也足以改善聚烯烃性能。与钯与烯烃与极性乙烯基单体的直接催化共聚相比，低成本的镍基催化剂的开发具有更高的亲氧性，因此更具挑战性。基于通过安装强供电子配体降低镍中心亲电性的优势，我们在此报告了新型双（N-酰化的咪唑啉-2-亚胺）镍配合物，用于降冰片烯聚合和与极性单体的共聚。此外，预期咪唑啉配体上的苯基取代基可提高镍催化剂对极性官能团的耐受性，从而使降冰片烯与市售丙烯酸甲酯共​​聚，可提供中等活性的高分子量官能化环烯烃共聚物（COC）和合理的共聚单体含量。