CHAPTER 9: Photochemistry in Ionic Liquids

This chapter is intended to show how the unique properties of ionic liquids (ILs) can be exploited advantageously to perform photochemical reactions. Photochemical excitation allows observation of phenomena and promotes reactivity that cannot be obtained from the singlet excited state that is characteristic of thermal reactions. In this chapter, after brief comments on the physical properties of ILs that are relevant in photochemistry such as polarity, viscosity and transparency, the main body of the text is aimed at exemplifying photochemical reactions that have been reported in ILs showing differences with respect to conventional solvents. Due to space limitations, rather than being comprehensive in the coverage of all the reactions reported in ILs, our purpose has been to provide a broad and general view of this area, with the emphasis on the opportunities that ILs as media can offer with respect to homogeneous and heterogeneous media. A final section summarizes our prospects for future developments in view of the current state of the art and the open issues still needing clarification.