美国斯坦福大学Xia, Yan团队开发了一种可控开环复分解共聚合成可降解聚合物的通用方法。相关研究成果于2021年11月18日发表于国际一流学术期刊《Nature Chemistry》。

降冰片烯衍生物（NBEs）是用于活性开环复分解聚合的常见单体，可获得低分散性和多种功能的聚合物。然而，聚NBEs的全碳主链是不可降解的。

该文报道了一种2，3-二氢呋喃与NBEs共聚合成可降解聚合物的方法。2,3-二氢呋喃与Grubbs催化剂快速反应，形成热力学稳定的Ru Fischer碳烯，这是共聚过程中唯一可检测到的活性Ru物种，NBEs的加入成为速率决定因素。该反应性减弱了NBE的均加成作用，并能够在整个共聚物中均匀加入酸降解的烯醇醚键，从而实现聚合物的完全降解，同时保持活性开环复分解聚合的有利特性。2,3-二氢呋喃与NBEs共聚得到具有溶解度可调、玻璃化转变温度和机械性能的低分散性聚合物。在温和的酸性条件下，该聚合物可以完全降解成小分子或低聚物。

该方法可适用于广泛使用的NBE的传统开环复分解聚合，以合成具有可调节性质的易于降解聚合物，用于各种应用和环境可持续性。

附：英文原文

Title: A versatile approach for the synthesis of degradable polymers via controlled ring-opening metathesis copolymerization

Author: Feist, John D., Lee, Daniel C., Xia, Yan

Issue&Volume: 2021-11-18

Abstract: Norbornene derivatives (NBEs) are common monomers for living ring-opening metathesis polymerization and yield polymers with low dispersities and diverse functionalities. However, the all-carbon backbone of poly-NBEs is non-degradable. Here we report a method to synthesize degradable polymers by copolymerizing 2,3-dihydrofuran with NBEs. 2,3-Dihydrofuran rapidly reacts with Grubbs catalyst to form a thermodynamically stable Ru Fischer carbene—the only detectable active Ru species during copolymerization—and the addition of NBEs becomes rate determining. This reactivity attenuates the NBE homoaddition and allows uniform incorporation of acid-degradable enol ether linkages throughout the copolymers, which enables complete polymer degradation while maintaining the favourable characteristics of living ring-opening metathesis polymerization. Copolymerization of 2,3-dihydrofuran with NBEs gives low dispersity polymers with tunable solubility, glass transition temperature and mechanical properties. These polymers can be fully degraded into small molecule or oligomeric species under mildly acidic conditions. This method can be readily adapted to traditional ring-opening metathesis polymerization of widely used NBEs to synthesize easily degradable polymers with tunable properties for various applications and for environmental sustainability.

DOI: 10.1038/s41557-021-00810-2

Source: https://www.nature.com/articles/s41557-021-00810-2