Anions as Dynamic Probes for Ionic Liquid Mixtures

Ionic liquid (IL) mixtures have been proposed as aviable alternative to rationallyfine-tune the physicochemicalproperties of ILs for a variety of applications. The understandingof the effects of mixing ILs on the properties of the mixtures ishowever only in the very early stages. Two series of ionic liquidmixtures, based on the 1-ethyl-3-methylimidazolium and 1-dodecyl-3-methylimidazolium cations, and having a commonanion (tetrafluoroborate or bis(trifluoromethylsulfonyl)imide),have been prepared and deeply characterized via multiple NMRtechniques. Diffusion and relaxation methods combined with 2Dion−ion correlation (nuclear Overhauser enhancement) experi-ments have been used for a better understanding of the interplaybetween dynamics and structure of IL mixtures. A crucial role ofthe anion in driving the mixture’s behavior emerged, making them important“dynamic probes”for gaining information of the polarand nonpolar regions of ionic liquids and their mixtures