A Dinuclear Mechanism Implicated in Controlled Carbene Polymerization.
A Dinuclear Mechanism Implicated in Controlled Carbene Polymerization.
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DOI：
10.1021/jacs.9b01532
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发表时间：
2019-04
影响因子：
15
通讯作者：
A. Zhukhovitskiy;Ilia J. Kobylianskii;Andy A Thomas;Austin M. Evans;Connor P. Delaney;Nathan C. Flanders
中科院分区：
文献类型：
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作者：
A. Zhukhovitskiy;Ilia J. Kobylianskii;Andy A Thomas;Austin M. Evans;Connor P. Delaney;Nathan C. Flanders
卡宾聚合提供了不能容易地由烯烃单体制备的聚烯烃;然而，受控和活性卡宾聚合一直是长期存在的挑战。本文报道了一类新的引发剂，（π-烯丙基）钯羧酸二聚体，它以可控的准活性方式取代了卡宾前体重氮乙酸乙酯，具有几乎定量的产率，聚合度>100，分子量分散度1.2-1.4，以及明确的，可多样化的链端。该方法还提供了经历微相分离的嵌段共聚卡宾。实验和理论的机制分析支持一个新的双核机制，这一过程。
Carbene polymerization provides polyolefins that cannot be readily prepared from olefin monomers; however, controlled and living carbene polymerization has been a long-standing challenge. Here we report a new class of initiators, (π-allyl)palladium carboxylate dimers, which polymerize ethyl diazoacetate, a carbene precursor in a controlled and quasi-living manner, with nearly quantitative yields, degrees of polymerization >100, molecular weight dispersities 1.2-1.4, and well-defined, diversifiable chain ends. This method also provides block copolycarbenes that undergo microphase segregation. Experimental and theoretical mechanistic analysis supports a new dinuclear mechanism for this process.