| Abstract
| - The nature of the interactions between 1,3-dialkylimidazolium cations and noncoordinating anions such astetrafluoroborate, hexafluorophosphate, and tetraphenylborate has been studied in the solid state by X-raydiffraction analysis and in solution by 1H NMR spectroscopy, conductivity, and microcalorimetry. In thesolid state, these compounds show an extended network of hydrogen-bonded cations and anions in whichone cation is surrounded by at least three anions and one anion is surrounded by at least three imidazoliumcations. In the pure form, imidazolium salts are better described as polymeric supramolecules of the type{[(DAI)3(X)]2+[(DAI)(X)3]2-}n (where DAI is the dialkylimidazolium cation and X is the anion) formed throughhydrogen bonds of the imidazolium cation with the anion. In solution, this supramolecular structural organizationis maintained to a great extent, at least in solvents of low dielectric constant, indicating that mixtures ofimidazolium ionic liquids with other molecules can be considered as nanostructured materials. This model isvery useful for the rationalization of the majority of the unusual behavior of the ionic liquids.
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