Theoretical investigation of the mechanism for the cycloaddition of CO2 to epoxides catalyzed by a magnesium(II) porphyrin complex
Theoretical investigation of the mechanism for the cycloaddition of CO2 to epoxides catalyzed by a magnesium(II) porphyrin complex
复制标题
镁(II)卟啉配合物催化CO2与环氧化物环加成机理的理论研究
DOI：
10.1007/s00894-015-2733-y
复制
发表时间：
2015-06
影响因子：
2.2
通讯作者：
Hai-Shun Wu
中科院分区：
文献类型：
--
作者：
Qin Wang;Cai-Hong Guo;Jianfeng Jia;Hai-Shun Wu
采用DFT方法研究了Mg(TPP)/TBAI （TPP =四苯基卟啉；TBAI =四丁基碘化铵）对环氧化合物CO2的环加成反应。研究了不同取代基的环氧化合物对反应机理的空间效应和电子效应。计算结果表明，在Mg（TPP）和TBAI的作用下，环加成反应的机理要比Mg（TPP）作为催化剂时容易得多。环氧化物的开环倾向于发生在甲基（Cα）或亚甲基（Cβ）碳上。预测了导致五元碳酸盐形成的合环步骤，以确定反应速率。对于烷基取代环氧化物，由于位阻因子占主导地位，β途径是有利的；对于具有强给电子基团的环氧化合物和苯乙烯氧化物，反应主要受电子因素控制，沿α途径进行。当环氧化物具有强吸电子基团（CF3）时，空间效应和电子效应都起重要作用。计算得到的Mg(TPP)/TBAI催化环氧化物与CO2的反应活性与实验结果吻合较好。
The cycloaddition of CO2 to epoxides, catalyzed by Mg(TPP)/TBAI (TPP = tetraphenylporphyrin; TBAI = tetrabutylammonium iodide), was investigated using DFT methods. Epoxides with various substituents were studied to explore steric and electronic effects on the reaction mechanism. Computational results show that the cycloaddition proceeds according to a much easier mechanism in the presence of Mg(TPP) and TBAI than the mechanism that takes place when Mg(TPP) is used as the catalyst. A preference for the epoxide ring-opening to occur at the methine (Cα) or methylene (Cβ) carbon was noted. The ring-closing step leading to the formation of a five-membered carbonate is predicted to determine the reaction rate. For alkyl-substituted epoxides, the β pathway is favorable since steric factors are dominant; for epoxides with a strongly electron-donating group and styrene oxide, the reaction is mainly controlled by electronic factors and proceeds along the α pathway. When the epoxide has a strongly electron-withdrawing group (CF3), both steric and electronic effects play important roles. The calculated reactivity of epoxides with CO2 catalyzed by Mg(TPP)/TBAI is in good agreement with that observed experimentally.
登录
查看更多内容
影响因子：
4.9
作者：
Y. Xiong;Hong Wang;Rongmin Wang;Yunfeng Yan;Bo Zheng;Yunpu Wang
通讯作者：
Y. Xiong;Hong Wang;Rongmin Wang;Yunfeng Yan;Bo Zheng;Yunpu Wang
固定化离子液体/氯化锌：二氧化碳和环氧化物合成环状碳酸酯的多相催化剂
影响因子：
--
作者：
Xia, Chun-Gu;Peng, Ha-Han;Xiao, Lin-Fei;Li, Fu-Wei
通讯作者：
Li, Fu-Wei
DOI：
10.1002/chin.200544258
发表时间：
2005-08
期刊：
ChemInform
影响因子：
--
作者：
Jianmin Sun;S. Fujita;M. Arai
通讯作者：
Jianmin Sun;S. Fujita;M. Arai
影响因子：
4.9
作者：
Hongzhou Yang;Yanlong Gu;Youquan Deng;Feng Shi
通讯作者：
Hongzhou Yang;Yanlong Gu;Youquan Deng;Feng Shi
影响因子：
4.4
作者：
HAY, PJ;WADT, WR
通讯作者：
WADT, WR