Reversible Photoactivated Phosphorescence of Gold(I) Arylethynyl Complexes in Aerated DMSO Solutions and Gels

Phosphorescence in fluid solutions at ambient temperature is usually quenched by molecular oxygen via energy transfer, and singlet oxygen is concomitantly sensitized. The long‐lived phosphorescence of a series of Au I arylethynyl complexes with tunable emission energies in aerated dimethyl sulfoxide (DMSO) solutions can be completely and repeatedly switched on by controlled photoirradiation. A trace amount of DMSO oxidation by the sensitized singlet oxygen is proposed to lead to a depletion of molecular oxygen in the local microenvironment of the Au I phosphor in the photoactivation processes. Harnessing the photoactivated phosphorescence and using UV light as a non‐contact pen, a writing–erasing–rewriting prototype has been demonstrated with a DMSO gel containing Au I arylethynyl complexes.