The scaled-charge additive force field for amino acid based ionic liquids

Andreeva²

2016

J Mol Model

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Recent success of the sodium-ion batteries fosters an academic interest for their investigation. Room-temperature ionic liquids (RTILs) constitute universal solvents providing non-volatility and non-flammability to electrolytes. In the present work, we consider four families of RTILs as prospective solvents for NaBF4 and NaNO3 with an inorganic salt concentration of 25 and 50 mol%. We propose a methodology to rate RTILs according to their solvation capability using parameters of the computed radial distribution functions. Hydrogen bonds between the cations and the anions of RTILs were found to indirectly favor sodium solvation, irrespective of the particular RTIL and its concentration. The best performance was recorded in the case of cholinium nitrate. The reported observations and correlations of ionic structures and properties offer important assistance to an emerging field of sodium-ion batteries. Graphical Abstract Sodium-ion electrolytes.

Section: Resultssupporting

confidence: 90%

Sodium-ion electrolytes based on ionic liquids: a role of cation-anion hydrogen bonding

Andreeva²

2016

J Mol Model

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“…The prevailing ionic structure that forms in the aqueous AAIL solutions is an ion pair, in accord with our recent finding that AAILs feature a single cation-anion coordination site [17]. That is, the ions prefer to coordinate to each other through the carboxyl group and acidic hydrogen atom on the imidazole ring, and they distribute themselves throughout the volume of water in the form of neutral cation-anion aggregates.…”

Section: Resultssupporting

confidence: 69%

“…Compare the size of the [ala] anion with the sizes of the [met] and [tpr] anions. As a rule, anions with larger radicals are less mobile than anions with smaller radicals [17]. However, a comprehensive investigation of transport phenomena in these water-containing systems is outside the scope of the present work.…”

Section: Resultsmentioning

confidence: 97%

“…This allowed us to gauge how well the AAILs are dispersed in water at every concentration and how this process can be modulated by the presence of an amino-acid structure. We applied a force field (FF) that we recently developed to the investigation of these AAILs [17]. This FF accounts for specific cation-anion nonbonded interactions using a straightforward, computationally inexpensive yet reliable fixed-charge approach.…”

Section: Introductionmentioning

confidence: 99%

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Mixtures of amino-acid based ionic liquids and water

Fileti

2015

J Mol Model

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New ionic liquids (ILs) involving increasing numbers of organic and inorganic ions are continuously being reported. We recently developed a new force field; in the present work, we applied that force field to investigate the structural properties of a few novel imidazolium-based ILs in aqueous mixtures via molecular dynamics (MD) simulations. Using cluster analysis, radial distribution functions, and spatial distribution functions, we argue that organic ions (imidazolium, deprotonated alanine, deprotonated methionine, deprotonated tryptophan) are well dispersed in aqueous media, irrespective of the IL content. Aqueous dispersions exhibit desirable properties for chemical engineering. The ILs exist as ion pairs in relatively dilute aqueous mixtures (10 mol%), while more concentrated mixtures feature a certain amount of larger ionic aggregates.

“…The latter fluctuates between 157 kJ mol -1 and 216 kJ mol -1 [30]. No experimental values for this important thermodynamic property are available thus far.This situation may indicate insufficient attention in the physical community to AAILs, which are mainly of interest for biophysical and biochemical applications.…”

mentioning

confidence: 99%

The force field for imidazolium-based ionic liquids: Novel anions with polar residues

Fileti

Chemical Physics Letters

2015

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Many molecules can be converted into ions via relatively simple procedures. These ions can be combined into ionic liquids (ILs). We develop a new force field (FF) for the seven selected AAILs comprising 1-ethyl-3-methylimidazolium cation and amino acid anions with polar residues. All anions were obtained via deprotonation of carboxyl group in analogy with acetate anion. We account for peculiar interactions between the anion and the cation by fitting electrostatic potential for an ion pair, in contrast to isolated ions. Furthermore, we account for hydrogen bonds obtained via electronic structure consideration. The developed model fosters computational investigation of ionic liquids.(1) Classical force field for amino acid ionic liquids was developed.(2) Electrostatic potential was derived using electronic structure description of a neutral ion pair.(3) The developed force field fosters numerical simulations of ionic liquids.