Molecular simulation of ionic liquids: current status and future opportunities

Abstract

Ionic liquids are salts that are liquid near ambient conditions. Interest in these unusual compounds has exploded in the last decade, both at the academic and commercial level. Molecular simulations based on classical potentials have played an important role in helping researchers understand how condensed phase properties of these materials are linked to chemical structure and composition. Simulations have also predicted many properties and unexpected phenomena that have subsequently been confirmed experimentally. The beneficial impact molecular simulations have had on this field is due in large part to excellent timing. Just when computing power and simulation methods matured to the point where complex fluids could be studied in great detail, a new class of materials virtually unknown to experimentalists came on the scene and demanded attention. This topical review explores some of the history of ionic liquid molecular simulations, and then gives examples of the recent use of molecular dynamics and Monte Carlo simulation in understanding the structure of ionic liquids, the sorption of small molecules in ionic liquids, the nature of ionic liquids in the vapor phase and the dynamics of ionic liquids. This review concludes with a discussion of some of the outstanding problems facing the ionic liquid modeling community and how condensed phase molecular simulation experts not presently working on ionic liquids might help advance the field.

Towards a Molecular Understanding of Cation–Anion Interactions—Probing the Electronic Structure of Imidazolium Ionic Liquids by NMR Spectroscopy, X‐ray Photoelectron Spectroscopy and Theoretical Calculations

“…[15][16][17] However, it was also shown that modified force fields with reduced (i.e., non-integer or fractional) charges on the ions considerably improve the MD results; [18,19] for details see the excellent review by Maginn. [20] When introducing such "effective charges" in computational chemistry, one might ask whether the value of this effective charge of a certain ion is a "real" quantity, implying some charge transfer between anion and cation, or whether it should be considered as a MD simulation parameter taking many body effects (e.g. polarisation) into account.…”

Thermophysical properties of imidazolium tricyanomethanide ionic liquids: experiments and molecular simulation

“…by theoretical/molecular simulation methods [12][13][14][15][16][17][18][19][20] and several predictive models have been proposed. 11,[21][22][23][24] Currently it is well accepted that ILs are highly structured fluids in which the ion pairs arrange themselves into polar and non-polar domains.…”

Understanding chemical reactions of CO2 and its isoelectronic molecules with 1-butyl-3-methylimidazolium acetate by changing the nature of the cation: The case of CS2 in 1-butyl-1-methylpyrrolidinium acetate studied by NMR spectroscopy and density functional theory calculations

“…[1][2][3][4][5][6][7][8][9][10][11] In this context, imidazolium acetate based ILs were proposed as systems able to capture comparatively to other ionic liquids, unusual amounts of carbon dioxide. 12,13 A number of investigations by us and others have shown that carbon dioxide dissolved in dried 1-butyl-3-methylimidazolium acetate [Bmim] [Ac] a) Author to whom correspondence should be addressed.…”