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高等学校化学研究 ›› 2011, Vol. 27 ›› Issue (4): 688-692.

• Articles • 上一篇    下一篇

Study of Imidazolium Ionic Liquids: Temperature-dependent Fluorescence and Molecular Dynamics Simulation

FU Hai-ying1, ZHU Guang-lai2, WU Guo-zhong1*, SHA Mao-lin1 and DOU Qiang1   

  1. 1. Laboratory of Radiation Chemistry, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, P. R. China;
    2. Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu 241000, P. R. China
  • 收稿日期:2010-08-13 修回日期:2010-10-30 出版日期:2011-07-25 发布日期:2011-06-29
  • 通讯作者: WU Guo-zhong E-mail:wugz@sinap.ac.cn
  • 基金资助:

    Supported by the National Natural Science Foundation of China(No.20973192, 11079007).

Study of Imidazolium Ionic Liquids: Temperature-dependent Fluorescence and Molecular Dynamics Simulation

FU Hai-ying1, ZHU Guang-lai2, WU Guo-zhong1*, SHA Mao-lin1 and DOU Qiang1   

  1. 1. Laboratory of Radiation Chemistry, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, P. R. China;
    2. Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu 241000, P. R. China
  • Received:2010-08-13 Revised:2010-10-30 Online:2011-07-25 Published:2011-06-29
  • Contact: WU Guo-zhong E-mail:wugz@sinap.ac.cn
  • Supported by:

    Supported by the National Natural Science Foundation of China(No.20973192, 11079007).

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摘要： The steady-state fluorescence spectra and molecular dynamics simulations were explored to investigate the temperature dependent organization in some imidazolium ionic liquids: 1-butyl-3-methylimidazolium hexafluorophosphate([bmim][PF6]), 1-ethyl-3-methylimidazolium ethylsulfate([emim][EtSO4]) and 1-butyl-3-methylimida- zolium tetrafluoroborate([bmim][BF4]). The pure room temperature ionic liquids(ILs) exhibit a large red shift at more than an excitation wavelength of around 340 nm, which demonstrates the heterogeneous nature of the liquids. Furthermore, the fluorescence spectra of the ionic liquids were found to be temperature-dependent. The emission intensity gradually decreased with increasing temperature for the neat ionic liquids and the mixed solutions of [bmim][BF4]-H2O, which was the special phenomena induced by not only the local structure but also the viscosity. The molecular dynamics simulation further confirms that the structures of ionic liquids are sensitive to the surroun- ding environment because of the aggregation degree of ILs.

关键词: Temperature dependence, Fluorescence, Ionic liquid, Molecular dynamics simulation

Abstract: The steady-state fluorescence spectra and molecular dynamics simulations were explored to investigate the temperature dependent organization in some imidazolium ionic liquids: 1-butyl-3-methylimidazolium hexafluorophosphate([bmim][PF6]), 1-ethyl-3-methylimidazolium ethylsulfate([emim][EtSO4]) and 1-butyl-3-methylimida- zolium tetrafluoroborate([bmim][BF4]). The pure room temperature ionic liquids(ILs) exhibit a large red shift at more than an excitation wavelength of around 340 nm, which demonstrates the heterogeneous nature of the liquids. Furthermore, the fluorescence spectra of the ionic liquids were found to be temperature-dependent. The emission intensity gradually decreased with increasing temperature for the neat ionic liquids and the mixed solutions of [bmim][BF4]-H2O, which was the special phenomena induced by not only the local structure but also the viscosity. The molecular dynamics simulation further confirms that the structures of ionic liquids are sensitive to the surroun- ding environment because of the aggregation degree of ILs.

Key words: Temperature dependence, Fluorescence, Ionic liquid, Molecular dynamics simulation