Structures and non-covalent interaction behaviours of binary systems containing the ionic liquid 1-(2′-hydroxylethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and chloroform

Mixtures of ionic liquids (ILs) and molecular solvents can overcome the drawbacks (high viscosity, high polarity, and high cost) of pure ILs and extend their practical use. The structural and interaction properties of ILs form the bases for understanding their properties. In this work, the structural properties of the mixtures of an IL, 1-(2'hydroxylethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2OHMIM][Tf2N]), with chloroform, a molecular solvent of weak polarity, in various concentrations were analysed using Fourier transform infrared spectroscopy and density functional theory calculations. Excess spectra were used to analyse the infrared spectra. The IL forms a stable ion cluster-CDCl3 complex with CDCl3 in the concentration range investigated. In the ion cluster-CDCl3 complex, the hydrogen atom of CDCl3 forms hydrogen-bonds with the fluorine atoms of the anion. In addition, the chlorine atom of CDCl3 forms a halogen-bond with the oxygen atom of the anion. All the hydrogen and halogen-bonds identified between the [C2OHMIM][Tf2N] ion cluster and CDCl3 exhibit low strength, closed shells, and electrostatically dominant interactions. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The study of mixtures helps to understand the structural properties of ionic liquids and molecular solvents, showing that within a certain concentration range, ionic liquids form stable ion cluster-CDCl3 complexes with chloroform, exhibiting low-strength hydrogen and halogen bonds.