Supramolecular effects involving the incorporation of guest substrates in imidazolium ionic liquid networks: Recent advances and future developments

Abstract

The interest in ionic liquids (ILs) as green solvents has grown enormously in the last few years. ILs have been proved to be convenient and economical solvents due to their efficiencies, non-toxicities and recyclabilities. Logically, these new media are used in a wide range of organic reactions. Recent investigations of the physicochemical properties of imidazolium ILs suggest that they behave as polymeric supramolecules that cannot be seen as conventional solvent. Electrostatic, H-bonds and π-stacking interactions occur in imidazolium ILs. When various organic compounds are mixed with imidazolium ILs, ‘inclusion complexes’ are formed and complex supramolecular organisation is created. In other words, ILs can be seen as a pre-organised medium that can modify the molecular reactivity (selectivity, substrate discrimination, etc.) by the formation of ‘inclusion complexes’ between guests (reactive species) and the ‘host networks’ (ILs). This mini review is intended to describe the imidazolium IL organisation (aggregation properties, formation of ‘inclusion complexes’, etc.) and to underline some of the effects on the organic reactivity of the inclusion of the guest substrates in imidazolium ILs.

Keywords:

• ionic liquids
• imidazolium salts
• host networks
• inclusion complexes
• organic reactions

Acknowledgements

We are grateful to the Natural Sciences and Engineering Research Council of Canada, the Fonds Quebécois de la Recherche sur la Nature et les Technologies, the Canada Foundation for Innovation and Université de Montréal for financial support. We also thank colleagues for careful reading and discussion of this manuscript.