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Abstract: In this paper, the structure of 1-carboxymethyl-3-methylimidazolium chloride was studied by X-ray diffraction, density functional theory, and FT–IR and Raman spectroscopic techniques for the first time. Title compound crystallizes in the orthorhombic space group Pca2 1 with the cell dimensions a =13.445 (6)Å, b =6.382 (3)Å, c =9.727 (5)Å and V =834.6 (7)Å3. All the geometrical parameters have been calculated using by B3LYP with 6–311G++(d,p) basis set. Optimized geometries have been compared with the experimental data, and the hydrogen bond and short contact interactions were discussed. The vibrational frequencies, infrared intensities and Raman scattering activities of the title compound were calculated at the same level. The observed bands were assigned based on the theoretical calculations. The scaled vibrational frequencies seem to coincide with the experimental data with acceptable deviations. [Copyright &y& Elsevier]

Abstract: The structures, vibrational frequencies, infrared and Raman intensities of hexafluorophosphate anion (PF6 −) and M+PF6 − (M+ =Li+, Na+, K+, Rb+ and Cs+) ion pairs have been studied by ab initio calculations. It is shown that the tridentate coordination of cation by PF6 − is the most stable structure in gas phase. The vibrational spectroscopies of the most stable geometries were calculated and the changes in band position were used to probe the ion associations. [Copyright &y& Elsevier]

The cation–cation π–π stacking is uncommon but it is essential for the understanding of some supramolecular structures. We explore theoretically the nature of non-covalent interaction occurring in the stacked structure within modeled clusters of 1,3-dimethylimidazolium and halide. The evidences of the energy decomposition analysis (EDA) and reduced density gradient (RDG) approach are different from those of common π–π interaction. Isosurfaces with RDG also illustrate the strength of the titled π–π interaction and their region. Additionally, we find that the occurrence of this interaction is attributed to a few C H···X interactions, as depicted using atom in molecule (AIM) method. This work presents a clear picture of the typical cation–cation π–π interaction and can serve to advance the understanding of this uncommon interaction. [ABSTRACT FROM AUTHOR]

Abstract: Solid polymer electrolytes are potentially useful electrolytes to be applied in high-energy batteries. In the present work, a novel polymer electrolyte, polyethylene oxide (PEO)–NaSCN–AlCl3, was prepared and investigated by FT-IR spectroscopic techniques. Based on the FT-IR data, the bands in the CN stretching envelope have been assigned and the effect of AlCl3 on ion–ion and ion–polymer interactions in the polymer electrolyte has been examined. It is shown that the Lewis acid–base interaction of AlCl3 with SCN1− leads to the formation of the complex anions AlCl3SCN− and Al2Cl6SCN−, depending on the content of AlCl3 and/or NaSCN in PEO; the preferential interactions of AlCl3 with crystal complex P(EO)3NaSCN occur in PEO–NaSCN–AlCl3 electrolytes; the AlCl3–NaSCN complex anions can play a plasticization role in PEO–NaSCN–AlCl3 electrolyte, and are expected to be a important factor to improve the conductivity and to enhance the cation transference number. In addition, the interactions between AlCl3 and ether oxygen of PEO were analyzed, and their effect on ionic association was also discussed. [Copyright &y& Elsevier]