Coordination Insertion Mechanism of Ring-Opening Polymerization of Lactide Catalyzed by Stannous Octoate
Coordination Insertion Mechanism of Ring-Opening Polymerization of Lactide Catalyzed by Stannous Octoate
复制标题
辛酸亚锡催化丙交酯开环聚合的配位插入机理
DOI：
10.1002/cjoc.202000519
复制
发表时间：
2021-05-27
影响因子：
5.4
通讯作者：
Ding, Jiandong
中科院分区：
文献类型：
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作者：
Rao, Weihan;Cai, Caiyun;Ding, Jiandong
主要观察和结论辛酸亚锡(SnOCT)(2)催化环酯开环聚合(ROP)是合成生物可降解脂肪族聚酯的主要方法，脂肪族聚酯是一类重要的可生物降解聚合物，在生物医用聚合物和环境友好材料领域得到了广泛的应用并仍在迅速发展。其潜在的机制被认为是通过配位-插入的方式，但由于缺乏直接的实验证据，该途径仍然是开放的。在这里，我们通过密度泛函理论(DFT)计算来探讨这一问题。根据我们的DFT计算和随后的Curtin-Hammett评估，羰基氧比酯氧具有显著的优势，因此环主要通过路径A而不是路径B打开。辛酸亚锡被确定为催化剂而不是引发剂。最后总结了丙交酯聚合过程中的主要阶段。
Main observation and conclusionRing-opening polymerization (ROP) of cyclic esters in the presence of stannous octoate (Sn(Oct)(2)) is the main way to obtain biodegradable aliphatic polyesters, an important family of biodegradable polymers which have been widely used and still rapidly developed in the fields of biomedical polymers and environment-friendly materials. The underlying mechanism is thought via a coordination-insertion way, but the pathway is still open owing to the absence of direct experimental evidence. Herein, we inquire this issue through density functional theory (DFT) calculations. According to our DFT calculations and the following Curtin-Hammett evaluation, the carbonyl oxygen has a significant advantage over the ester oxygen, and thus the ring is opened mainly through pathway A instead of pathway B. The stannous octoate is identified as a catalyst rather than an initiator. We eventually summarize the main stages during the whole polymerization of lactide.