A cyclic thioenone system capable of controlled ring-opening polymerization (ROP) is presented that leverages a reversible Michael addition–elimination (MAE) mechanism. The cyclic thioenone monomers are easy to access and modify and for the first time incorporate the dynamic reversibility of MAE with chain-growth polymerization. This strategy features mild polymerization conditions, tunable functionalities, controlled molecular weights (M_n), and narrow dispersities. The obtained polythioenones exhibit excellent optical transparency and good mechanical properties and can be depolymerized to recover the original monomers. Density functional theory (DFT) calculations of model reactions offer insights into the role of monomer conformation in the polymerization process, as well as explaining divergent reactivity observed in seven-membered thiepane (TP) and eight-membered thiocane (TC) ring systems. Collectively, these findings demonstrate the feasibility of MAE mechanisms in ring-opening polymerization and provide important guidelines toward future monomer designs.

中文翻译：

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迈克尔加成-消除开环聚合


提出了一种能够进行受控开环聚合（ROP）的环状硫烯酮系统，该系统利用可逆迈克尔加成-消除（MAE）机制。环状硫烯酮单体易于获取和改性，并且首次将 MAE 的动态可逆性与链增长聚合相结合。该策略具有温和的聚合条件、可调的官能团、受控的分子量（M _n ）和窄的分散度。所得聚硫烯酮表现出优异的光学透明度和良好的机械性能，并且可以解聚以回收原始单体。模型反应的密度泛函理论 (DFT) 计算可深入了解单体构象在聚合过程中的作用，并解释在七元硫杂环己烷 (TP) 和八元硫杂环己烷 (TC) 环系统中观察到的不同反应性。总的来说，这些发现证明了 MAE 机制在开环聚合中的可行性，并为未来的单体设计提供了重要指导。