Copolymerization of ethylene (E) and polar vinyl monomers remains a problem because E propagation is hindered. Herein, for the first time, we report the copolymerization of E and polar styrenes (S^R) by using an oxophilic scandium catalyst that exhibits higher turnover frequencies than both E and S^R homopolymerizations when R is an electron‐withdrawing group. This positive comonomer effect was elucidated through computing reaction profiles of E/S^F copolymerization at the DFT (B3PW91) level of theory. It reveals that the secondary interaction between Sc³⁺ and phenyl of the last and penultimate inserted S^F units leads to a decrease of the E insertion barrier, because the electron‐withdrawing substituent enhances the electrophilicity of Sc³⁺ by an inductive effect mediated by the secondary interaction. After three consecutive insertions of the E units, the secondary interaction is lost and the S^F insertion is kinetically preferred over the E insertion. This process is in line with the NMR spectrum analyses which show that the resultant copolymers mainly contain S^R(E)_xS^R sequences where x≤3.

中文翻译：

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极性苯乙烯对Scan催化乙烯与乙烯共聚的机理及作用

乙烯（E）和极性乙烯基单体的共聚仍然是一个问题，因为阻碍了E的传播。在此，我们首次报道了使用亲氧性catalyst催化剂进行E和极性苯乙烯（S ^R）的共聚，当R为吸电子基团时，它比E和S ^R均聚均具有更高的周转率。通过在理论的DFT（B3PW91）水平上计算E / S ^F共聚的反应曲线，可以阐明这种积极的共聚单体效应。结果表明，Sc ³⁺与倒数第二个插入的S ^F的苯基之间存在二次相互作用单位导致E插入势垒的减小，因为吸电子取代基通过二次相互作用介导的感应作用增强了Sc ³⁺的亲电性。后的E单元的三个连续的插入，次级相互作用丢失和S ^˚F插入在动力学上优选通过E插入。这个过程是在与NMR谱分析，其表明，所得到的共聚物主要含有的S line ^{- [R}（E）_X小号^ř序列，其中x≤3。