分子内C—H键胺化反应机理的DFT研究  

Mechanism of intramolecular C—H amination investigated by DFT method

作　　者：沈文[1] 王渭娜[1] 靳玲侠[1] 王文亮[1] 

机构地区：[1]陕西师范大学化学与化工学院,陕西西安710119

出　　处：《分子科学学报》2015年第3期251-257,共7页Journal of Molecular Science

基　　金：国家自然科学基金资助项目(21173139);陕西省重点科技创新团队资助项目(2013KCT-17)

摘　　要：采用密度泛函理论研究了溴化亚铁催化芳基叠氮化物C—H键胺化生成苯并咪唑的反应机理.研究结果表明,溴化亚铁催化剂使反应由协同机理转变为分步机理,反应活化能降低了大约167kJ/mol.催化反应由氮气消去、C—N形成和2H-苯并咪唑异构化3个基元步骤组成.其中金属亚胺/金属氮烯FeNR PhNCPh进攻C形成C—N键是无能垒过程,且与金属氮烯中氮的电荷密切相关.氮气消去与2H-苯并咪唑异构化反应的能垒均在41~54kJ/mol之间.The mechanism of iron（Ⅱ）bromide-catalyzed intramolecular C—H amination with aryl azides as the substrates to produce benzimidazoles was investigated by DFT calculations.The results show that Iron catalyst can change the reaction from concerted to stepwise which are N（2）eilimination,C—N bond formation and isomeration,and thus the activation energy is reduced by about 167kJ/mol.The C—N formation process involves metal imido complex/metal-nitrene Fe NR PhN CPh attacking electrophilic C to form C—N bond barrierlessly,which is markedly impacted by the negative charge of the metal-nitrene N.The activation energies of N2 elimination are about 41-54kJ/mol,similar to that of the isomerization reactions.

关 键 词：叠氮化物 金属氮烯 C—H键胺化 催化机理 DFT 

分 类 号：O643[理学—物理化学]