Solvation and Aggregation of N,N′-Dialkylimidazolium Ionic Liquids: A Multinuclear NMR Spectroscopy and Molecular Dynamics Simulation Study

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• 作者：Richard C. Remsing ; Zhiwei Liu ; Ivan Sergeyev ; Guillermo Moyna
• 刊名：Journal of Physical Chemistry B
• 出版年：2008
• 出版时间：June 26, 2008
• 年：2008
• 卷：112
• 期：25
• 页码：7363 - 7369
• 全文大小：743K
• 年卷期：v.112,no.25(June 26, 2008)
• ISSN：1520-5207

文摘

The solvation and aggregation of the ionic liquid (IL) 1-n-butyl-3-methylimidazolium chloride ([C₄mim]Cl) in water and dimethylsulfoxide (DMSO) were examined by analysis of ¹H and ^35/37Cl chemical shift perturbations and molecular dynamics (MD) simulations. Evidence of aggregation of the IL n-butyl chains in aqueous environments at IL concentrations of 75−80 wt% was observed both in the NMR experiments and in the MD simulations. The studies also show that [C₄mim]Cl behaves as a typical electrolyte in water, with both ions completely solvated at low concentrations. On the other hand, the data reveal that the interactions between the [C₄mim]⁺ and Cl⁻ ions strengthen as the DMSO content of the solutions increases, and IL-rich clusters persist in this solvent even at concentrations below 10 wt%. These results provide an experimentally supported atomistic explanation of the effects that these two solvents have on some of the macroscopic properties of [C₄mim]Cl. The implications that these findings could have on the design of IL-based solvent systems are briefly discussed.