高等学校化学学报

高等学校化学学报 ›› 2009, Vol. 30 ›› Issue (8): 1615.

• 研究论文 • 上一篇    下一篇

[EPy][BF4]和[EPy][PF6]离子对的气相及液相阴阳离子相互作用研究

万辉, 王小露, 管国锋   

  1. 南京工业大学化学化工学院, 南京 210009
  • 收稿日期:2008-07-14 出版日期:2009-08-10 发布日期:2009-08-10
  • 通讯作者: 管国锋, 男, 博士, 教授, 主要从事计算化学、化工分离研究. E-mail: guangf@njut.edu.cn
  • 基金资助:

    江苏省自然科学基金(批准号: BK2005121)资助.

Interaction Between Cation and Anion in Ion-pairs of [EPy][BF4] and [EPy][PF6] in Gas and Liquid Phases

WAN Hui, WANG Xiao-Lu, GUAN Guo-Feng*   

  1. College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
  • Received:2008-07-14 Online:2009-08-10 Published:2009-08-10
  • Contact: GUAN Guo-Feng. E-mail: guangf@njut.edu.cn
  • Supported by:

    江苏省自然科学基金(批准号: BK2005121)资助.

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摘要：

采用从头算HF/6-31G和密度泛函理论B3LYP/6-31+G(d,p)方法, 对乙基吡啶四氟硼酸盐([EPy][BF4])和乙基吡啶六氟磷酸盐([EPy][PF6])的离子对进行了结构优化和频率分析, 并利用自洽反应场(SCRF)的导体极化连续模型(CPCM)考察了离子对液态下的结构及相互作用, 得到了两种离子对的红外光谱及气相、液相下最稳定结构. 由两种离子对的几何参数可知, 阴阳离子通过氢键相互作用, 两种离子液体的红外光谱特征值与实验值比较吻合. 应用自然键轨道(NBO)理论分析了吡啶阳离子及离子对中的原子电荷分布和电荷转移情况, 结果表明两种离子对中阴阳离子间存在静电相互作用和氢键作用. 通过几何参数、相互作用能及NBO分析研究发现, 液相下由于周围电荷的中和作用, 离子对中阴阳离子的相互作用明显降低.

关键词: 离子液体; 密度泛函理论; 自然键轨道; 导体极化连续模型

Abstract:

The geometry structure optimization and frequency analysis of ion pairs of ionic liquids 1-ethylpyridinium tetrafluoroborate([EPy][BF4]) and 1-ethylpyridinium hexafluorophosphate([EPy][PF6]) were studied using ab initio method and density functional theory at HF/6-31G and B3LYP/6-311+G(d,p) level. Structure and interaction of ionic liquids in liquid phase were investigated by conductor-like polarizable conti-nuum model(CPCM). The most stable structures in gas and liquid phases and infrared spectra of two ionic liquids were obtained. Hydrogen bonding interaction between anion and cation was confirmed by geometry parameters of two ion pairs. The simulated infrared spectra agreed well with the experimental spectra. Natural bond orbital(NBO) analysis was performed to analyze atomic charge distribution and charges transfer in [EPy]+ cation and ionic liquids. The results show there are electrostatic interaction and hydrogen bonding interaction between cation and anion of ionic liquids. By means of geometry parameters, interaction energy and NBO analysis, because of neutralization of surrounding charges, interaction in liquid phase becomes smaller.

Key words: Ionic liquid; Density functional theory(DFT); Natural bond orbital(NBO); Conductor- like polarizable continuum model(CPCM)

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