Chen Jiazhen, Gao Yanshan, Marks Tobin J
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
Angew Chem Int Ed Engl. 2020 Aug 24;59(35):14726-14735. doi: 10.1002/anie.202000060. Epub 2020 May 27.
Introducing polar functional groups into widely used polyolefins can enhance polymer surface, rheological, mixing, and other properties, potentially upgrading polyolefins for advanced, value-added applications. The metal catalyst-mediated copolymerization of non-polar olefins with polar comonomers represents the seemingly most straightforward, atom- and energy-efficient approach for synthesizing polar functionalized polyolefins. However, electrophilic early transition metal (groups 3 and 4)-catalyzed processes which have achieved remarkable success in conventional olefin polymerizations, encounter severe limitations here, largely associated with the Lewis basicity of the polar co-monomers. In recent years, however, new catalytic systems have been developed and successful strategies have emerged. In this Minireview, we summarize the recent progress in early transition metal polymerization catalyst development, categorized by the catalytic metal complex and polar comonomer identity. Furthermore, we discuss advances in the mechanistic understanding of these polymerizations, focusing on critical challenges and strategies that mitigate them.
将极性官能团引入广泛使用的聚烯烃中，可以改善聚合物的表面、流变、混合及其他性能，有可能将聚烯烃升级用于先进的增值应用。非极性烯烃与极性共聚单体的金属催化剂介导的共聚反应，似乎是合成极性官能化聚烯烃最直接、原子和能源效率最高的方法。然而，在传统烯烃聚合中取得显著成功的亲电早期过渡金属（第3和第4族）催化过程，在此处却遇到了严重限制，这在很大程度上与极性共聚单体的路易斯碱性有关。不过，近年来已开发出新的催化体系，并出现了成功的策略。在本综述中，我们按催化金属配合物和极性共聚单体类型，总结了早期过渡金属聚合催化剂开发的最新进展。此外，我们还讨论了这些聚合反应机理理解方面的进展，重点关注关键挑战及应对策略。
