Cis-Selective Metathesis to Enhance the Living Character of Ring-Opening Polymerization: An Approach to Sequenced Copolymers,ACS Macro Letters

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Cis-Selective Metathesis to Enhance the Living Character of Ring-Opening Polymerization: An Approach to Sequenced Copolymers
ACS Macro Letters ( IF 5.1 ) Pub Date : 2018-06-29 00:00:00 , DOI: 10.1021/acsmacrolett.8b00460
Amy L Short ₁ , Cheng Fang _{1,

2} , Jamie A Nowalk ₁ , Ryan M Weiss ₁ , Peng Liu ₁ , Tara Y Meyer _{1,

3}

Affiliation

The hydrolytic behavior and physical properties of a polymer are directly related to its constituent monomer sequence, yet the scalable and controllable synthesis of sequenced copolymers remains scarcely realized. To address this need, an enhanced version of entropy-driven ring-opening metathesis polymerization (ED-ROMP) has been developed. An unprecedented level of control is obtained by exploiting the kinetic and thermodynamic differences in the metathesis activity of cis- and trans-olefins embedded in large, unstrained macrocycles. First-order rate kinetics were observed, and polymer molecular weights were found to be proportional to catalyst loading. Computational analysis suggests that incorporation of a cis-olefin into the monomer backbone both introduces a thermodynamic driving force and increases the population of metathesis-active conformers. This approach offers a generally applicable method for enhancing living character in ED-ROMP.

中文翻译：

顺式选择性复分解以增强开环聚合的活性：一种序列共聚物的方法

聚合物的水解行为和物理性质与其组成单体序列直接相关，但序列共聚物的可扩展和可控合成仍然很少实现。为了满足这一需求，开发了熵驱动的开环复分解聚合（ED-ROMP）的增强版本。通过利用嵌入在大的、无应变的大环中的顺式和反式烯烃的复分解活性的动力学和热力学差异，获得了前所未有的控制水平。观察到一级速率动力学，发现聚合物分子量与催化剂负载量成正比。计算分析表明，结合一个顺式烯烃进入单体主链既引入了热力学驱动力，又增加了复分解活性构象异构体的数量。这种方法提供了一种普遍适用的方法来增强 ED-ROMP 中的生活特性。

更新日期：2018-06-29

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