Crystal engineering with ionic liquids

At first sight, it may seem a surprise that CrystEngComm has a collection concentrating on ionic liquids; but within the last decade, these solvents have expanded their use from the more traditional fields of electrochemistry, separation or catalysis, to new, less explored areas in materials chemistry and crystal engineering. The research presented herein showcases some of the latest advances in these areas.

Crystallisation strategies using ionic liquids are naturally quite different from conventional organic solvents and require the development of new methodologies. Importantly, ionic liquids are not just replacing organic solvents, but they often give results that are very different from conventional pathways and therefore have the potential for exciting new discoveries. Despite their increasing use in inorganic and materials chemistry, there is still the need for fundamental investigations; for example, into the nature of the interactions between the ionic liquid ions and the solutes.

Within this collection, the reader will find remarkable examples of the use of ionic liquids as multifunctional media for crystallisation, with the ionic liquids acting, for example, as both solvents and templates, and/or additives. There are interesting insights into how the ionic liquids affect crystal growth as well as the structures of biomolecules, nanoparticles or polymers. Due to the stability of ionic liquids under high vacuum and high temperatures, they are applied not only in classic solvent-based techniques but also in others, such as vacuum deposition. Crystallographic analyses of new ionic liquids are also presented. These help to understand the factors that influence the supramolecular arrangements of the ions and allow some insight into solvent–solute interactions.

We hope that this collection of articles are an inspiration on the many possibilities that these fascinating solvents can offer.

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