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A series of task-specific ionic liquids (TSILs) based on glycerylimidazolium cations have been prepared by reaction of 1-chloropropanediol, a compound obtainable from glycerol (a widely available and in-expensive waste product), with the appropriate base (1-H-imidazole, 1,2-dimethylimidazole and 1-methyl-1-H-imidazole). The reaction of 3-(1H-imidazol-1-yl)propane-1,2-diol with chloroalkanes, bromoalkanes and alkyl mesylates gave the corresponding salts which were characterized. The possibility to use these ILs in palladium catalyzed reactions was evaluated, evidencing good catalyst stability and a high recyclability. [ABSTRACT FROM AUTHOR]

Room temperature ionic liquids (ILs) are stable liquids composed of anions and cations. 1-ethyl-3-methyl-imidazolium (EMIm, EMI) is a popular and important cation that produces thermally stable ILs with various anions. In this study two amide-type anions, bis(trifluoro-methanesulfonyl)amide [N(SO2CF3)2, TFSA, TFSI, NTf2, or Tf2N] and bis(fluorosulfonyl)amide [(N(SO2F)2, FSA, or FSI] were investigated by multinuclear NMR spectroscopy. In addition to EMIm-TFSA and EMIm-FSA, lithium-salt-doped binary systems were prepared (EMIm-TFSA-Li and EMIm-FSA-Li). The spin-lattice relaxation times (T1) were measured by 1H, 19F, and 7Li NMR spectroscopy and the correlation times of 1H NMR, τc(EMIm) (8 × 10-10 to 3 × 10-11 s) for the librational molecular motion of EMIm and those of 7Li NMR, τc(Li) (5 × 10-9 to 2 × 10-10 s) for a lithium jump were evaluated in the temperature range between 253 and 353 K. We found that the bulk viscosity (η) versus τc(EMIm) and cation diffusion coefficient DEMIm versus the rate 1/τc(EMIm) have good relationships. Similarly, linear relations were obtained for the η versus τc(Li) and the lithium diffusion coefficient DLi versus the rate 1/τc(Li). The mean one-jump distances of Li were calculated from τc(Li) and DLi. The experimental values for the diffusion coefficients, ionic conductivity, viscosity, and density in our previous paper were analyzed by the Stokes-Einstein, Nernst-Einstein, and Stokes-Einstein-Debye equations for the neat and binary ILs to clarify the physicochemical properties and mobility of individual ions. The deviations from the classical equations are discussed. [ABSTRACT FROM AUTHOR]

Description of the local microscopic structure in ionic liquids (ILs) is a prerequisite to obtain a comprehensive understanding of the influence of the nature of ions on the properties of ILs. The local structure is mainly determined by the spatial arrangement of the nearest neighboring ions. Therefore, the main interaction patterns in ILs, such as cation-anion H-bond-like motifs, cation-cation alkyl tail aggregation, and ring stacking, were considered within the framework of the nearest-neighbor approach with respect to each particular interaction site. We employed classical molecular dynamics (MD) simulations to study in detail the spatial, radial, and orientational relative distribution of ions in a set of imidazolium-based ILs, in which the 1-butyl-3-methylimidazolium (C4mim+) cation is coupled with the acetate (OAc-), chloride (Cl-), tetrafluoroborate (BF4 -), hexafluorophosphate (PF6 -), trifluoromethanesulfonate (TfO-), or bis(trifluoromethanesulfonyl)amide (TFSA-) anion. It was established that several structural properties are strongly anion-specific, while some can be treated as universally applicable to ILs, regardless of the nature of the anion. Namely, strongly basic anions, such as OAc- and Cl-, prefer to be located in the imidazolium ring plane next to the C-H2/4-5 sites. By contrast, the other four bulky and weakly coordinating anions tend to occupy positions above/below the plane. Similarly, the H-bond-like interactions involving the H² site are found to be particularly enhanced in comparison with the ones at H4-5 in the case of asymmetric and/or more basic anions (C4mimOAc, C4mimCl, C4mimTfO, and C4mimTFSA), in accordance with recent spectroscopic and theoretical findings. Other IL-specific details related to the multiple H-bond-like binding and cation stacking issues are also discussed in this paper. The secondary H-bonding of anions with the alkyl hydrogen atoms of cations as well as the cation-cation alkyl chain aggregation turned out to be poorly sensitive to the nature of the anion. [ABSTRACT FROM AUTHOR]

Supportedionic liquid membranes (SILMs) are promising tools for the separationof carbon dioxide from other gases. In this paper, new imidazolium,pyrrolidinium, piperidinium, and morpholinium ionic liquids with atriethylene glycol side chain and tosylate anions, as well as theirsymmetrical dicationic analogues, have been synthesized and incorporatedinto SILMs. The selectivities for CO2/N2andCO2/CH4separations have been measured. Theselectivities exhibited by the dicationic ionic liquids are up totwo times higher than the values of the corresponding monocationicionic liquids. Quantum chemical calculations have been used to investigatethe difference in the interaction of carbon dioxide with monocationicand dicationic ionic liquids. The reason for the increased gas separationselectivity of the dicationic ionic liquids is two-fold: (1) a decreasein permeance of nitrogen and methane through the ionic liquid layer,presumably due to their less favorable interactions with the gases,while the permeance of carbon dioxide is reduced much less; (2) anincrease in the number of interaction sites for the interactions withthe quadrupolar carbon dioxide molecules in the dicationic ionic liquids,compared to the monocationic analogues. [ABSTRACT FROM AUTHOR]

Abstract: The material known as 1-butyl-3-methylimidazolium hydroxide has been reported to be a 1:1 mixture of [BMIM]-cations and [OH]-anions and, as such, has been widely cited as a basic ionic liquid. 1,3-Disubstituted imidazolium-cations however, are prone to deprotonation at the C2-position of the imidazolium ring, a property readily exploited for the preparation of N-heterocyclic carbenes. Consequently, this reactivity may be unexpected and especially unwelcome when it leads to the decomposition of “[BMIM][OH]” itself, especially if the decomposition occurs during its use as a basic catalyst or reaction medium. Here, we highlight the putative “[BMIM][OH]”, as a case of particular inconsistency and inaccuracy in the literature and aim to dispel some of the persisting confusion surrounding its preparation, characterisation and use. The first part of this paper concerns the history, preparation and identity of so-called “[BMIM][OH]”, whilst the second part highlights some of the claimed activity, effects and problems associated with its use. Despite warnings in the literature, reports are still appearing in which mechanistic interpretations of reaction pathways and results are made without consideration of the unwanted reactivities of the 1,3-disubstituted imidazolium-cations employed. Future publications in which the use of “[BMIM][OH]” is reported should take into account the acidity of the [BMIM]-cation and the consequences this has for the chemistry being studied. [Copyright &y& Elsevier]

Abstract: The structural and thermal behavior of energetic salts based on N,N′-dinitrourea (DNU) should be fully investigated for their further applications. In the present paper, the crystal structure and vibrational spectrum of imidazolium N,N′-dinitrourea ([IMI][DNU]) were investigated in detail. A slight twist or torsion was found in the cation and anion because of their interactions. These interactions also formed a stabilized hydrogen bond network. The vibrations of the functional groups were mainly exhibited in an infrared (IR) spectrum, and the skeletal stretching vibrations mainly appeared in a Raman spectrum. The non-isothermal kinetics of the title compound and its mixture with polyethylene glycol 10000 (PEG10000) were investigated with the methods of Kissinger and Ozawa. In situ IR analysis, mass spectral fragmentation, and bond dissociation enthalpy calculations showed that the initial decomposition step of [IMI][DNU] was the breakage of the N the anion. The in situ IR of gaseous phase products and mass spectral fragmentation indicated that the main final products of [IMI][DNU] decomposition were N2O and imidazole. [Copyright &y& Elsevier]

Abstract: Infrared spectra of the powdered (C3N2H5)5Bi2Cl11, (C3N2H5)5Bi2Br11and (C3N2H5)5Sb2Br11 crystals in the region of internal vibrations of the imidazolium cations (3600 and 400cm−1) at the temperature intervals of 10–300K, covering paraelectric–ferroelectric phase transitions, are presented and discussed in this paper. The research shows that the vibrational states of the imidazolium cations change markedly during the paraelectric–ferroelectric phase transition. The continuous nature of these transitions is well reflected in the infrared spectra, which is consistent with the previous X-ray and dielectric findings. [Copyright &y& Elsevier]

Owing to their favorable properties, ionic liquids have recently gained recognition as possibly environmentally benign solvents. Now among the most promising industrial chemicals, they have already been labeled “green”, but this appellation seems due entirely to their very low vapor pressure. This growing interest in the various applications of ionic liquids will soon result in their presence in the environment. Therefore, reliable analytical tools for the environmental analysis of ionic liquids need to be developed urgently. This paper presents a newly developed analytical procedure for the enrichment of 1-alkyl- and 1-aryl-3-methylimidazolium ionic liquids from water samples. The method is based on cation exchange solid-phase extraction followed by selective elution. Pre-concentrated samples are subjected to high-performance liquid chromatography (HPLC) with an advanced methodology for qualitative and quantitative analysis. The overall procedure was verified by using standard spiked samples of tap water, seawater, and freshwater. [ABSTRACT FROM AUTHOR]

• An interesting supramolecular architecture was obtained by simple synthesis method. • The imidazole sulfate [(HIm) 2 SO 4 and water molecules form a cage-like structure. • This anionic water cluster structure can provide the understanding of SO 4 2− in H 2 O. An interesting compound of supramolecular architecture has been reported in this paper. The molecular formula is [(NiIm 6)SO 4 2 [(HIm) 2 SO 4 4 ·6H 2 O (Im= imidazole). Analysis of crystal structure data shows that the imidazole sulfate [(HIm) 2 SO 4 and water molecules form a cage-like structure, then surround the metal nickel complex in the center of the cage. Six water molecules form a large ring structure with six SO 4 2− by strong hydrogen bonding. The tetrahedron structure of six SO 4 2− and eight imidazole positive ions pass through N-H···O hydrogen bonds form a cage-like structure, enclosing [NiIm 6 2+ positive ions. The compound was characterized by single-crystal X-ray diffraction, Hirshfeld surface analysis, thermogravimetric analysis, infrared spectroscopy and cyclic voltammogram analysis. [Display omitted] The imidazole sulfate [(HIm) 2 SO 4 and water molecules form a 3 D cage-like structure, then surround the [NiIm 6 2+ complex in the center of the cage through the ionic electrostatic interaction and the strong hydrogen bond interaction. [ABSTRACT FROM AUTHOR]