Visible Light and Copper Complexes: A Promising Match in Photoredox Catalysis

Copper-based complexes have proven recently to be versatile catalysts in visible light mediated organic reactions. Copper complexes have been applied in photocatalytic hydrogen production from water, as photosensitizers in photoelectrochemical cells, or as active components in organic light emitting diodes (OLED); however, their use as photoredox catalysts for organic synthesis has been rare until recently. Thus, photoactive copper complexes offer the advantage of tuning their properties by changing the nature of the chelating ligands to meet the requirements for a given photochemical process. The benefits of copper catalysis in combination with ultraviolet (UV) light have been recognized for sometime in processes such as [2+2] cycloadditions or atom transfer radical additions (ATRA). Copper complexes might be able to establish themselves as viable alternatives to ruthenium or iridium complexes as visible light catalysts in many photoredox catalyzed reactions.