Ionic liquid photocatalysts in organic transformations

Abstract

Ionic liquids (ILs), as one of the most attractive functional materials in recent decades, have been widely used in many fields due to their unique physicochemical properties. ILs are composed of organic cations and inorganic/organic anions, which determine their high degree of designability. Especially in the field of chemical catalysis, ideal catalysts can be precisely designed according to their high degree of designability. In the past few decades, ILs have been extensively studied as catalysts in the field of thermal catalysis, while there are few reports on ILs in photocatalytic organic synthesis. In this review, we systematically summarize the recent advances of ionic liquids as photocatalysts in organic synthesis, focusing on elucidating the role of ILs in photocatalytic reactions. According to the different mechanisms of ILs in photoreactions, they are divided into three categories: (1) ligand-to-metal charge transfer (LMCT)-type ILs; (2) single electron transfer (SET)-type ILs; (3) hydrogen atom transfer (HAT)-type ILs. We hope that this review can provide a prospective overview of this topic and stimulate research interest.