Fluorescence Probing of the Physicochemical Characteristics of the Room Temperature Ionic Liquids

Abstract

Room temperature ionic liquids are salts, which in their pure state are liquid at ambient conditions. These substances have attracted a great deal of attention in recent years for the various opportunities they offer. Several physicochemical characteristics of these novel materials can be understood from fluorescence studies on carefully chosen probe molecules in these media. In this chapter, we address some of the properties of these complex media that have been obtained from these fluorescence studies. Specifically, we discuss about the polarity of these liquids, solvent relaxation dynamics in these media and properties that arise as a consequence of slow solvation and diffusion in these viscous environments. The microheterogeneous nature of these solvents, which is indicated in some of the fluorescence studies, is also highlighted. The steady state and time-resolved fluorescence response of the molecular systems presented here is expected to provide insight into the various structural and dynamical aspects of these complex media and will also initiate further studies to throw light into some of the properties that are not yet fully understood.