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化学学报
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化学学报 ›› 2011, Vol. 69 ›› Issue (22): 2682-2690. 上一篇    下一篇

研究论文

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

吴阳*，范翠娥，张丽娜，孔玉霞   

  1. (辽宁大学化学院 沈阳 110036)
  • 投稿日期:2011-04-28 修回日期:2011-06-23 发布日期:2011-07-02
  • 通讯作者: 吴阳 E-mail:wuyoung@hotmail.com
  • 基金资助:

    氨基酸离子液体新型极化电荷模型和分子动力学模拟;金属离子选择性功能离子液体的合成、性质及分子动力学模拟;应用于相分离技术的氨基酸离子液体的功能化设计与分子动力学模拟

A Theoretical Investigation of Ionic Liquids Formed between Protonated betaine Cation and bis(trifluoromethylsulfonyl)imide Anion

WU Yang, FAN Cui-E, ZHANG Li-Na, KONG Yu-Xia   

  1. (College of Chemistry, Liaoning University, Shenyang 110036)
  • Received:2011-04-28 Revised:2011-06-23 Published:2011-07-02

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被引次数

6

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.

关键词: 离子液体, [Hbet][Tf2N], 氢键, NPA, NBO, AIM (atoms in molecules)

The interaction mechanisms between protonated betaine cation ([Hbet]＋) and bis(trifluoromethylsulfonyl)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 analysis of cation-anion interactions provides some initial hints as to the structural factors contributed to melting point and selective extraction of metal ions.

Key words: ionic liquids, [Hbet][Tf2N], H-bonds, natural population analysis (NPA), NBO, atoms in molecules (AIM)