Light-induced electron transfer in Tl[Ag(CN)2]: Photochemical reaction of luminescent metal–metal exciplexes in the solid state

Photoluminescence spectra of Tl[Ag(CN)2] as a function of exposure time are reported. UV irradiation of a Tl[Ag(CN)2] crystal at low temperature (77 K) results in a decrease of the luminescence intensity and creation of a non-luminescing species. The process is reversible by heating the sample to room temperature so that the original luminescing species is reformed again. A light-induced electron transfer mechanism is proposed in which a [Ag(CN)2]3 3− trimer is reduced to a [Ag(CN)2]3 4− trimer by Tl+.