The interactions between polar solvents (methanol, acetonitrile, dimethylsulfoxide) and the ionic liquid 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide

Computational NMR Study of Ion Pairing of 1-Decyl-3-methyl-imidazolium Chloride in Molecular Solvents

“… 37 Even though acetonitrile is rather similar to DMSO in polarity, it does not seem to break ionic aggregates into separate ions, apparently due to the poorer hydrogen-bond accepting abilities. 45 , 48 − 50 Varying degrees of dissociation of the [C4mim]-based 35 , 51 , 52 and ammonium-based 41 ILs in acetonitrile solution were, however, reported. At low concentrations in nonpolar solvents, ILs tend to form supramolecular aggregates, 35 , 44 , 51 , 53 − 55 although lone contact ion pairs were seen to be the dominant association pattern for some ILs in chloroform 47 and dichloromethane.…”

“…To rationalize the modulating effect of the molecular solvent on the properties of the IL, a thorough understanding of intermolecular interactions between the constituent ionic and molecular species that govern molecular association in the mixture is crucial. , At lower concentrations of the IL in the molecular solvent, ion pairing is an important phenomenon, where the dynamic equilibrium between free ions, solvent-separated and contact ion pairs, and higher-order neutral or charged ionic aggregates is established, which is sensitive to the concentration of the IL. , There is a general trend for polar solvents to be capable of breaking the ion pairs into separate ions, while nonpolar solvents tend to favor ion aggregation. , This can be exemplified by the association constants of 1-butyl-3-methyl-imidazolium tetrafluoroborate, [C4mim]­[BF 4 ], which range from the order of 10 5 dm 3 /mol in dichloromethane, DCM, to 10 –1 dm 3 /mol in water . Indeed, the low-concentration aqueous solutions of ILs behave as traditional electrolytes, where ions are virtually completely solvated, ,− although in some instances ion pairing was detected even at rather low concentrations of the IL. , Dimethyl sulfoxide, DMSO, has also demonstrated the capability of breaking ionic aggregates into separate ions, ,− but, here too, some ILs have displayed slight association at high dilutions. , Remarkably, however, higher-order supramolecular ionic clusters were found to persist at rather low concentrations of [C4mim]­[Cl] IL in DMSO . Even though acetonitrile is rather similar to DMSO in polarity, it does not seem to break ionic aggregates into separate ions, apparently due to the poorer hydrogen-bond accepting abilities. ,− Varying degrees of dissociation of the [C4mim]-based ,, and ammonium-based ILs in acetonitrile solution were, however, reported.…”

“…Indeed, the low-concentration aqueous solutions of ILs behave as traditional electrolytes, where ions are virtually completely solvated, ,− although in some instances ion pairing was detected even at rather low concentrations of the IL. , Dimethyl sulfoxide, DMSO, has also demonstrated the capability of breaking ionic aggregates into separate ions, ,− but, here too, some ILs have displayed slight association at high dilutions. , Remarkably, however, higher-order supramolecular ionic clusters were found to persist at rather low concentrations of [C4mim]­[Cl] IL in DMSO . Even though acetonitrile is rather similar to DMSO in polarity, it does not seem to break ionic aggregates into separate ions, apparently due to the poorer hydrogen-bond accepting abilities. ,− Varying degrees of dissociation of the [C4mim]-based ,, and ammonium-based ILs in acetonitrile solution were, however, reported. At low concentrations in nonpolar solvents, ILs tend to form supramolecular aggregates, ,,,− although lone contact ion pairs were seen to be the dominant association pattern for some ILs in chloroform and dichloromethane. , However, the dissociation of [C4mim]­[Cl] ion pairs into separate ions in solutions of chloroform and carbon tetrachloride has been observed very recently. , …”

Ion Pairs of 1-Butyl-3-Methylimidazolium Triflate Do Not Dissociate in Propan-1-ol: A Vibrational Spectroscopic Viewpoint

“…This ideal spectrum is then subtracted from the experimentally measured mixture spectrum. A detailed description can be found in [16,17]. The effects of excess mixing volume were compensated using density data determined by a vibrating tube densitometer (DMA 5000, Anton Paar GmbH, Graz, Austria).…”

Comparative Study of Physical Properties and CO2 Solubility of Ammonium and Sulfonium Ionic Liquids in Mixture with Glutaronitrile

“…Mixtures of ILs with protic molecular solvents such as water, alcohols, amides, and so forth ,, or aprotic solvents such as ACN, alkylcarbonates, DMSO, or DMF , improve the properties of ILs by lowering their viscosity and promoting ionic dissociations while retaining their thermal and electrochemical properties, unlike mineral salts, whose solubility in molecular solvents is often limited (close to 1–2 mol L –1 ) . ILs often composed of asymmetrical organic cations are much more soluble or miscible in all proportions. ,, The cross-interactions between ion liquid ions and molecular solvent molecules depend on several factors: the presence of a labile proton, the size of ions, the nature of the heteroatom (S, N, P) in the cation (sulfonium, ammonium, or phosphonium), , the length of the carbon chain of the cation or anion, , and also the properties of the molecular solvent chosen to make the mixture. , Among the solvents suitable for electrochemical applications, nitriles and more specifically dinitriles , have emerged as a base for electrolytes for batteries, , supercapacitors, and other energy storage applications. , Among dinitriles, glutaronitrile (GLN) is emerging as an electrochemically stable and safe solvent very suitable for various applications − …”