Lesch Volker, Heuer Andreas, Holm Christian, Smiatek Jens
Helmholtz-Institut Münster: Ionics in Energy Storage (IEK-12), Forschungszentrum Jülich, Münster (Germany).
Institute of Physical Chemistry, University of Münster, Münster, Germany.
Chemphyschem. 2016 Feb 3;17(3):387-94. doi: 10.1002/cphc.201501021. Epub 2015 Dec 23.
The solvation and the dynamic properties of apolar model solutes in alkyl imidazolium-based ionic liquids (IL) are studied by using all-atom molecular dynamics simulations. In regards to specific IL effects, we focused on the often used 1-ethyl-3-methyl imidazolium cation in combination with the anions tetrafluoroborate, acetate, and bis(trifluoromethanesulfonyl)imide. Our findings reveal that the size of the anion crucially influences the accumulation behavior of the cations, which results in modified IL solvation properties. Deviations between the different alkyl imidazolium-based IL combinations can be also observed with regard to the results for the radial distribution functions, the number of surrounding molecules, and the molecular orientation. The analysis of the van Hove function further shows pronounced differences in the dynamic behavior of the solutes. The simulations verify that the solute mobilities are mainly influenced by the composition of the local solvent shell and the properties of the underlying Lennard-Jones interactions. Additional simulations with regard to modified short-range dispersion energies for alkyl imidazolium-based ILs validate our conclusions.
通过全原子分子动力学模拟研究了非极性模型溶质在基于烷基咪唑鎓的离子液体（IL）中的溶剂化和动力学性质。关于特定的离子液体效应，我们重点关注常用的1-乙基-3-甲基咪唑鎓阳离子与四氟硼酸根、醋酸根和双（三氟甲磺酰）亚胺阴离子的组合。我们的研究结果表明，阴离子的大小对阳离子的聚集行为有至关重要的影响，这导致了离子液体溶剂化性质的改变。在径向分布函数、周围分子数量和分子取向的结果方面，也可以观察到不同基于烷基咪唑鎓的离子液体组合之间的差异。对范霍夫函数的分析进一步表明溶质的动力学行为存在明显差异。模拟验证了溶质迁移率主要受局部溶剂壳层的组成和潜在的 Lennard-Jones 相互作用的性质影响。关于基于烷基咪唑鎓的离子液体的改性短程色散能的额外模拟验证了我们的结论。
