Proton transfer and polarity changes in ionic liquid-water mixtures: a perspective on hydrogen bonds from ab initio molecular dynamics at the example of 1-ethyl-3-methylimidazolium acetate-water mixtures-Part 1
Proton transfer and polarity changes in ionic liquid-water mixtures: a perspective on hydrogen bonds from ab initio molecular dynamics at the example of 1-ethyl-3-methylimidazolium acetate-water mixtures-Part 1
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DOI：
10.1039/c2cp23983c
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发表时间：
2012-01-01
影响因子：
3.3
通讯作者：
Kirchner, Barbara
中科院分区：
文献类型：
--
作者：
Brehm, Martin;Weber, Henry;Kirchner, Barbara
离子液体1-乙基-3-甲基咪唑乙酸盐[C（2）C（1）Im][OAc]对强氢键材料具有很好的溶解能力，这与其在纯液体中存在强氢键网络有关。理解溶剂化过程的第一步是表征离子液体的氢键能力。离子液体中氢键的描述是一个有争议的问题，因为这种介质的复杂性。本文的目的是合理化不仅在离子液体中的氢键的存在，但也要分析它们对纯液体的结构的影响，以及如何存在的水，离子液体固有的杂质，影响这种类型的相互作用。我们进行了广泛的研究，使用从头算分子动力学的离子液体1-乙基-3-甲基咪唑乙酸盐与水的混合物的结构，在不同的水含量。氢键存在于纯液体中，并且水的存在改变并在很大程度上干扰离子液体的氢键网络，并且还影响其他杂质（卡宾）的形成和离子的偶极矩。从头算分子动力学的使用是探索离子液体中氢键的推荐工具，因为显式电子结构计算与凝聚相的研究相结合。
The ionic liquid 1-ethyl-3-methylimidazolium acetate [C(2)C(1)Im][OAc] shows a great potential to dissolve strongly hydrogen bonded materials, related with the presence of a strong hydrogen bond network in the pure liquid. A first step towards understanding the solvation process is characterising the hydrogen bonding ability of the ionic liquid. The description of hydrogen bonds in ionic liquids is a question under debate, given the complex nature of this media. The purpose of the present article is to rationalise not only the existence of hydrogen bonds in ionic liquids, but also to analyse their influence on the structure of the pure liquid and how the presence of water, an impurity inherent to ionic liquids, affects this type of interaction. We perform an extensive study using ab initio molecular dynamics on the structure of mixtures of the ionic liquid 1-ethyl-3-methylimidazolium acetate with water, at different water contents. Hydrogen bonds are present in the pure liquid, and the presence of water modifies and largely disturbs the hydrogen bond network of the ionic liquid, and also affects the formation of other impurities (carbenes) and the dipole moment of the ions. The use of ab initio molecular dynamics is the recommended tool to explore hydrogen bonding in ionic liquids, as an explicit electronic structure calculation is combined with the study of the condensed phase.