物理化学学报 >> 2015, Vol. 31 >> Issue (4): 653-659.doi: 10.3866/PKU.WHXB201502031

热力学,动力学和结构化学 上一篇    下一篇

分子间作用力对咪唑盐介晶相性质的影响

王猛1, 潘旭1, 戴松元1,2, 陈健1   

  1. 1 中国科学院等离子体物理研究所, 中国科学院新型薄膜太阳电池重点实验室, 合肥230031;
    2 华北电力大学, 新型薄膜太阳电池北京市重点实验室, 北京102206
  • 收稿日期:2014-11-21 修回日期:2015-02-02 发布日期:2015-04-03
  • 通讯作者: 潘旭, 戴松元 E-mail:mars_dark@Hotmail;sydai@ipp.ac.cn
  • 基金资助:

    国家重点基础研究发展规划项目(973) (2011CBA00700), 国家高技术研究发展计划项目(863) (2011AA050510), 国家自然科学基金(21103197,21273242)及中国博士后科学基金(2013M540526)资助

Influence of Intermolecular Interactions on the Mesogenic Properties of Imidazolium Salts

WANG Meng1, PAN Xu1, DAI Song-Yuan1,2, CHEN Jian1   

  1. 1 Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, P. R. China;
    2 Beijing Key Laboratory of Novel Thin Film Solar Cell, North China Electric Power University, Beijing 102206, P. R. China
  • Received:2014-11-21 Revised:2015-02-02 Published:2015-04-03
  • Contact: PAN Xu, DAI Song-Yuan E-mail:mars_dark@Hotmail;sydai@ipp.ac.cn
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2011CBA00700), National High Technology Research and Development Program of China (863) (2011AA050510), National Natural Science Foundation of China (21103197, 21273242), National Science Foundation for Post-doctoral Scientists of China (2013M540526).

摘要:

通过对咪唑环1位(N1)取代烷基、3位(N3)取代基及阴离子的修饰合成了一系列具有近晶A (SmA)相的咪唑类离子液晶. 利用差示扫描量热法、单晶衍射、小角度X射线衍射等手段研究了咪唑盐的介晶相温度范围、介晶态的结构, 并测量了部分咪唑盐的各向异性导电率. 结果表明, 咪唑环N1取代烷基、N3取代基及咪唑盐的阴离子会改变分子间范德华力和氢键, 从而对咪唑盐的介晶相性质产生影响. 此外, 当乙烯基引入到咪唑环N3位置时, 咪唑盐相邻的层结构之间形成π-π堆积作用, 不仅有利于介晶态的形成, 同时使氟硼酸类离子液晶具有最大的层间距和最小的各向异性导电率. 这一结果表明, 调控离子液晶的性质时必须综合考虑各种分子间作用力的影响.

关键词: 咪唑盐, 介晶相性质, 范德华作用, 氢键, π-π堆积

Abstract:

Aseries of imidazolium salt-based ionic liquid crystals with a smectic A(SmA) phase are synthesized by altering the substituents attached to the 1-position (N1) and 3-position (N3) of the imidazolium ring, and anions. The mesogenic properties of the imidazolium salts, including mesophase temperature range and structural properties, are studied by differential scanning calorimetry, small-angle X-ray diffraction, and single crystal diffraction. The anisotropic ion conductivities of several ionic liquid crystals are also measured. It is found that substituents attached to N1 or N3 and the anions influence the van der Waals interactions and hydrogen bond, which results in a significant effect on the mesogenic properties of the imidazolium salts. Moreover, when a vinyl group is attached to the N3 position, π-π stacking interactions form between adjacent layers. This not only benefits the formation of a mesophase but also results in the biggest layer spacing and lowest anisotropic ion conductivities for imidazolium tetrafluoroborates. These results suggest that all intermolecular interactions should be taken into account when regulating the mesogenic properties of ionic liquid crystals.

Key words: Imidazolium salts, Mesogenic property, van der Waals interaction, Hydrogen bond, π-π stacking

MSC2000: 

  • O641