Vibrational relaxation in ionic liquids and ionic liquid reverse micelles

We report static and ultrafast IR studies of Fe(CN)5NO2− and W(CO)6 in bulk ionic liquids and of ionic liquid reverse micelles. For Fe(CN)5NO2− and W(CO)6 in ionic liquids, the vibrational frequencies appear to scale with solute–solvent interaction strength, but the vibrational energy relaxation (VER) times are longer than in methanol and DMSO. The VER times in the reverse micelles are consistent with a solvation environment that has mixed surfactant and ionic liquid and is more polar than the bulk ionic liquid. These results differ from previous ionic liquid reverse micelle studies.