质子化甜菜碱阳离子与双三氟甲磺酰亚胺阴离子相互作用的理论研究  

A Theoretical Investigation of Ionic Liquids Formed between Proto-nated Betaine Cation and Bis(trifluoromethylsulfonyl)imide Anion

作　　者：吴阳[1] 范翠娥[1] 张丽娜[1] 孔玉霞[1] 

机构地区：[1]辽宁大学化学院,沈阳110036

出　　处：《化学学报》2011年第22期2682-2690,共9页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20703021);辽宁省自然科学基金(No.20102088);辽宁省创新团队基金(No.2008T074)

摘　　要：利用密度泛函理论(DFT)方法,在B3LYP/6-311+G(d,p)水平下,对质子化甜菜碱阳离子与双三氟甲磺酰亚胺阴离子形成的气态阴阳离子对([Hbet][Tf2N])进行理论研究,通过几何结构优化和频率分析得到势能面上的六个稳定构型.计算结果表明[Hbet]+和[Tf2N]-之间能够形成较强的氢键相互作用,氢键相互作用的稳定化能主要来源于[Tf2N]-中O,N原子的孤对电子和[Hbet]+中参与形成氢键的O—H,C—H反键轨道之间的相互作用.自然布局分析(NPA)给出气态[Hbet][Tf2N]离子对中阴阳离子间的电荷转移比传统离子液体中电荷转移的数值小.AIM(atoms in molecules)分析得到[Hbet]+和[Tf2N]-之间的氢键相互作用以静电作用为主.通过实验和理论结果相比较,初步探讨影响离子液体熔点及其对金属离子选择性溶解的结构因素.The interaction mechanisms between protonated betaine cation （[Hbet]＋） and bis（trifluoro- methylsulfonyl）imide anion （[Tf2N]） were investigated at the B3LYP/6-311 ＋G（d,p） level, and six stable isomers of [Hbet][Tf2N] were optimized. The optimized structures, energies and natural population analysis （NPA） were presented and analyzed in terms of their possible correlation with the interaction energies and the H-bond separations. Theoretical results indicate that the [Hbet]~ and [Tf2N]- can form considerably strong H-bond interactions, which is mainly attributed to the interaction between the lone pairs of O, N atoms in [Tf2N]- and the antibonding orbital of O--H, C--H in [Hbet]~. Atoms in molecules （AIM） analyses indicate that the H-bond between [Hbet]＋ and [Tf2N]- is primarily ionic character. The preliminary analy- sis of cation-anion interactions provides some initial hints as to the structural factors contributed to melting point and selective extraction of metal ions.

关 键 词：离子液体 [Hbet][Tf2N] 氢键 NPA NBO AIM(atoms in molecules) 

分 类 号：O621.1[理学—有机化学]