Redox-active photocatalytic N^C cyclometalated gold(III) catecholate complexes.

The redox properties and photocatalytic activity of four N^C cyclometalated Au(III) catecholate complexes were investigated. They proved competent for the photocatalytic C-H arylation of furan with aryldiazonium salts under green LED irradiation. UV-vis studies supported the formation of electron donor-acceptor adducts between the Au(III) catecholate complexes and diazonium salts, enabling photoinduced electron transfer and aryl radical generation. Electrochemical, EPR, and DFT studies evidenced ligand-centered redox activity and the formation of Au(III) semiquinone species.