Photochemical processes in ionic liquids on ultrafast timescales.

The number of investigations of room temperature ionic liquids (RTILs) has been developing rapidly in recent years, e.g., due to their potential use as "green solvents" in many industrial applications. A large body of data has been accumulated on physico-chemical properties including ultrafast dynamics of these liquids. This review deals both with the generation and the subsequent relaxation dynamics of selected transient species following photolysis or pulse radiolysis of RTILs with special emphasis on the exceptional character of imidazolium based systems. Although considerable progress has been made, the understanding of the photochemistry of ionic liquids is just at its embryonic stage. Nevertheless, a brief comparison with high temperature ionic liquids (HTILs) such as alkali metal doped alkali halide mixtures already reveals important differences.