Photooxidation of AuCl₂⁻ and AuBr₂⁻ Induced by ds Excitation

In the presence of electron acceptors such as CHzC12 or 02, the irradiation of AuC12- or AuBrz- in acetonitrile led to the photooxidation of Au(1) to Au(II1). AuC14- and AuBr4- were formed as final products when additional halide was present. The reactive excited states were of the metal-centered ds type. The photooxidations were reversed in solutions of ethanol. AuC14- and AuBr4- underwent a photoreduction to AuC12- and AuBrz-, respectively