Elucidation of Substantial Differences in Ring-Opening Polymerization Outcomes from Subtle Variation of Glucose Carbonate-Based Monomer Substitution Patterns and Substituent Types
Elucidation of Substantial Differences in Ring-Opening Polymerization Outcomes from Subtle Variation of Glucose Carbonate-Based Monomer Substitution Patterns and Substituent Types
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DOI：
10.1021/jacs.3c03339
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发表时间：
2023-07
影响因子：
15
通讯作者：
Yidan Shen;Mingwan Leng;Yunchong Yang;Senthil K. Boopathi;Guorong Sun;K. Wooley
中科院分区：
文献类型：
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作者：
Yidan Shen;Mingwan Leng;Yunchong Yang;Senthil K. Boopathi;Guorong Sun;K. Wooley
发现五元双环葡萄糖碳酸酯单体上存在的取代基极大地影响开环聚合（ROP）期间的反应性和区域选择性，这与先前对类似系统的研究形成显著和有趣的对比，同时也导致对所得聚碳酸酯的热性质的可预测的影响。在三种不同的有机碱催化剂的催化下，探索了一系列具有4，6-醚、-碳酸酯或-磺酰基氨基甲酸酯保护基团的五种五元双环2，3-葡萄糖-碳酸酯单体的聚合行为。不考虑所用的有机碱催化剂，区域规则的聚碳酸酯通过与醚取代基的单体的ROP获得，而衍生自具有碳酸酯保护基的单体的聚合物的主链连接性遭受转羰基化反应，导致不规则的主链连接性和宽的摩尔质量分布。磺酰基氨基甲酸酯保护的单体不能进行有机碱催化的ROP，可能是由于氨基甲酸酯官能团中质子的酸性。通过热稳定性和玻璃化转变温度（Tg）研究了含醚基和碳酸酯基的聚碳酸酯的热行为。当叔丁氧羰基（BOC）基团被用作保护侧链时，观察到两阶段的热分解，而所有其他聚碳酸酯呈现出高的热稳定性与单阶段的热降解。Tg受侧链膨松性的影响很大，其值范围为39至139 °C。葡萄糖基聚碳酸酯的这些基本发现可能有助于开发下一代可持续的高功能材料。
The substituents present upon five-membered bicyclic glucose carbonate monomers were found to greatly affect the reactivities and regioselectivities during ring-opening polymerization (ROP), which contrast in significant and interesting ways from previous studies on similar systems, while also leading to predictable effects on the thermal properties of the resulting polycarbonates. Polymerization behaviors were probed for a series of five five-membered bicyclic 2,3-glucose-carbonate monomers having 4,6-ether, -carbonate, or -sulfonyl urethane protecting groups, under catalysis with three different organobase catalysts. Irrespective of the organobase catalyst employed, regioregular polycarbonates were obtained via ROP of monomers with ether substituents, while the backbone connectivities of polymers derived from monomers with carbonate protecting groups suffered transcarbonylation reactions, resulting in irregular backbone connectivities and broad molar mass distributions. The sulfonyl urethane-protected monomers were unable to undergo organobase-catalyzed ROP, possibly due to the acidity of the proton in urethane functionality. The thermal behaviors of polycarbonates with ether and carbonate pendant groups were investigated in terms of thermal stability and glass transition temperature (Tg). A two-stage thermal decomposition was observed when tert-butyloxycarbonyl (BOC) groups were employed as protecting side chains, while all other polycarbonates presented high thermal stabilities with a single-stage thermal degradation. Tg was greatly affected by side-chain bulkiness, with values ranging from 39 to 139 °C. These fundamental findings of glucose-based polycarbonates may facilitate the development of next-generation sustainable highly functional materials.