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The surface tension and contact angle of a homologues series of chiral 3-alkyl-1-[(1 R ,2 S ,5 R )-(−)-menthoxymethyl]imidazolium bis(trifluoromethylsulfonyl)imide ionic liquids (ILs), [C n -im-CH 2 OMen][NTf 2 ], n = 1–10 were investigated. Despite the complex structure, the theoretical surface tensions calculated based on a modified parachor concept agree well with experimental values. The contact angle of the investigated ILs was measured on poly(tetrafluoroethylene), polypropylene, optical quality glass, stainless and acid resistant steel, and aluminum alloy. The results obtained show that the presence of (1 R ,2 S ,5 R )-(−)-menthol in imidazolium cation affects the impact of the length of the alkyl chain on the surface activity of these substances. It was also found that bis(trifluoromethylsulfonyl)imides with the natural chiral substituent (1 R ,2 S ,5 R )-(−)-menthol in imidazolium cation reveal very good wetting abilities on all surfaces, or they can seep into solid materials as in poly(tetrafluoroethylene) film. The good wettability of [C n -im-CH 2 OMen][NTf 2 ] ILs on non-polar surface correlates very well with their ability to drain the surface charge of similar material. [ABSTRACT FROM AUTHOR]

Research has been conducted on the biotic activity of eight chiral ionic liquids (CILs) with a natural component in the form of (-)-menthol with the configuration (1R,2S,5R) against Basidiomycetes and Fungi imperfecti. Optically active imidazolium salts were tested as follows: several asymmetric 3-alkyl-1-[(1R,2S,5R)-(-)- menthoxymethyl]imidazolium chlorides with various alkyl substituents (from methyl to dodecyl) and one symmetric 1,3-bis[(1R,2S,5R)-(-)-menthoxymethyl]imidazolium chloride containing two (1R,2S,5R)-(-)-menthol substituents. Mycological tests were carried out with brown-rot and white-rot fungi, as well as with filamentous fungi, i.e. mold fungi and blue stain fungi. The new, optically active compounds demonstrated diverse effectiveness of fungicidal activity, which was dependent on the chemical structure of the functional groups. The natural (-)-menthol component, introduced as a substituent in ionic liquids, turned out to be an optically active compound with activity against wood-destroying fungi. (1R,2S,5R)-(-)-menthol was especially active against the fungi tested. The fungicidal value of imidazolium chloride with two (-)-menthol substituents against Coniophora puteana ranged from 1.8 to 2.9 kg m-3. The adsorption processes on Scots pine wood and resistance to water leaching were examined. The sorption properties of symmetric salts with two optical active (-)-menthol substituents fitted very well with the Freundlich adsorption model. Attenuated total reflection-infrared (ATR-IR) spectra confirmed that methylene groups of the aliphatic substituent, the ring of the heterocyclic imidazole, as well as the ether bridge of the natural (-)-menthol component were fixed in the structure of the impregnated pine wood (Pinus sylvestris L.). The positive results encourage further investigation of the potential application of novel functional CILs (Figure 1) for wood protection. [ABSTRACT FROM AUTHOR]

We present the specific cooperative effect of a semisynthetic glycopeptide antibiotic teicoplanin and chiral ionic liquids containing the (1 R,2 S,5 R)-(-)-menthol moiety on the chiral recognition of enantiomers of mandelic acid, vanilmandelic acid, and phenyllactic acid. Experiments were performed chromatographically on an Astec Chirobiotic T chiral stationary phase applying the mobile phase with the addition of the chiral ionic liquids. The stereoselective binding of enantiomers to teicoplanin in presence of new chiral ionic liquids were evaluated applying thermodynamic measurements and the docking simulations. Both the experimental and theoretical methods revealed that the chiral recognition of enantiomers in the presence of new chiral ionic liquids was enthalpy driven. The changes of the teicoplanin conformation occurring upon binding of the chiral ionic liquids are responsible for the differences in the standard changes in Gibbs energy (Δ G0) values obtained for complexes formed by the R and S enantiomers and teicoplanin. Docking simulations revealed the steric adjustment between the chiral ionic liquids cyclohexane ring (chair conformation) and the β- d-glucosamine ring of teicoplanin and additionally hydrophobic interactions between the decanoic aliphatic chain of teicoplanin and the alkyl group of the tested salts. The obtained terpene derivatives can be considered as 'structural task-specific ionic liquids' responsible for enhancing the chiral resolution in synergistic systems with two chiral selectors. [ABSTRACT FROM AUTHOR]

Mixtures of nematic liquid crystals (LCs) with chiral ionic liquids (CILs) may find application as active materials for electrically driven broadband mirrors. Five nematic liquid crystal hosts were mixed with twenty three ionic liquids, including chiral ones, and studied in terms of their miscibility within the nematic phase. Phase diagrams of the mixtures with CILs which exhibited twisted nematic phase were determined. Miscibility, at levels between 2 and 5 wt%, was found in six mixtures with cyanobiphenyl-based liquid crystal host—E7. On the other hand, the highest changes in the isotropization temperature was found in the mixtures with isothiocyanate-based liquid crystal host—1825. Occurrence of chemical reactions was found. A novel chiral binaphtyl-based organic salt [N11116][BNDP] was synthesized and, in reaction to the 1825 host, resulted in high helical twisting power product(s). Selectivity of the reaction with the isothiocyanate-based liquid crystal was found. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are chemical compounds composed of ions with melting points below 100 °C exhibiting a design feature. ILs are commonly used as the so-called green solvents, reagents or highly efficient catalysts in varied chemical processes. The huge application potential of ionic liquids (IL) justifies the growing interest in these compounds. In the last decade, increasing attention has been devoted to the development of new methods in the synthesis of stable chiral ionic liquids (CILs) and their application in various separation techniques. The beginnings of the successful use of CILs to separate enantiomers date back to the 1990 s. Most chiral ILs are based on chiral cations or chiral anions. There is also a limited number of CILs possessing both a chiral cation and a chiral anion. Due to the high molecular diversity of both ions, of which at least one has a chiral center, we have the possibility to design a large variety of optically active structures, thus expanding the range of CIL applications. Research utilizing chiral ionic liquids only recently has become more popular. However, it is the area that still has great potential for future development. This review aimed to describe the diversity of structures, properties and examples of applications of chiral ionic liquids as new chiral solid materials and chiral components of the anisotropic environment, providing chiral recognition of enantiomeric analytes, which is useful in liquid chromatography, countercurrent chromatography and other various CIL-based extraction techniques including aqueous biphasic (ABS) extraction systems, solid–liquid two-phase systems, liquid–liquid extraction systems with hydrophilic CILs, liquid–liquid extraction systems with hydrophobic CILs, solid-phase extraction and induced-precipitation techniques developed in the recent years. The growing demand for pure enantiomers in the pharmaceutical and food industries sparks further development in the field of extraction and separation systems modified with CILs highlighting them as affordable and environmentally friendly both chiral selectors and solvents. [ABSTRACT FROM AUTHOR]

A comprehensive physico-chemical characterization of the chiral ionic liquids of a 3-alkyl-1-[(1 R ,2 S ,5 R )-(–)-menthoxymethyl]imidazolium bis(trifluoromethylsulfonyl)imides homologous series with a linear alkyl substituent ranging from the methyl up to the dodecyl group was carried out experimentally to investigate the way in which the measured thermophysical properties were influenced by the alkyl chain length on the cation. Refractive index, density, speed of sound, and isobaric heat capacity were measured as a function of temperature at atmospheric pressure and analyzed by methods based on mathematical gnostics. A robust linear regression along a gnostic influence function was used to optimize parameters of the relationships used in this work and to estimate the changing nanosegregation in the studied ionic liquid series by finding the Critical Alkyl Length Size (CALS) from heat capacity data. In addition, we propose the use of the marginal analysis to assess the quality of the measured data as an alternative to the estimate of the measurement uncertainty. [ABSTRACT FROM AUTHOR]