吲哚取代氮杂环卡宾配位币族金属催化剂催化羧化CO_(2)的理论研究

Theoretical study on carboxylation of CO_(2)catalyzed by indole-substituted N-heterocyclic Carbene coordination coin metal catalysts

为探究配体在催化反应活性中的作用,以及不同币族金属的氮杂环卡宾(NHC)催化剂催化CO_(2)的羧化偶联反应催化性能的差异,借助密度泛函理论方法,对吲哚基取代NHC配体Cu/Ag/Au催化剂的CO_(2)羧化偶联反应进行理论计算.结果表明,CO_(2)插入到金属—碳键是反应的决速步.通过对其过渡态非共价相互作用分析表明,提升催化剂性能的关键在于NHC配体能与CO_(2)形成氢键,降低反应能垒,而不是配体位阻效应.此外,从理论上预测NHC-Ag和NHC-Au催化剂的催化性能不及NHC-Cu催化剂主要是因为电子因素.

To explore the role of ligands in catalytic reaction activity and the differences in catalytic performance of CO_(2)carboxylation coupling reaction catalyzed by different N-heterocyclic Carbene(NHC)-metal catalysts,the density functional theory method was used to theoretically calculate the process of CO_(2)carboxylation coupling reaction catalyzed by indole-substituted NHC-Cu/Ag/Au complexes.The results showed that the insertion of CO_(2)into the metal—carbon bond was the rate-determining step of the reaction.The noncovalent interaction results of its transition state revealed that the key to improving the performance of the catalyst was to reduce the reaction energy barrier by the formation of a hydrogen bond between the NHC ligand and CO_(2),rather than the steric hindrance effect of the ligand.In addition,the results theoretically predicted that the catalytic performances of NHC-Ag and NHC-Au catalysts is inferior to that of NHC-Cu catalyst due to electronic factors.