Room-Temperature Phosphorescence Vapochromism through Conformational Control

Solid-state room-temperature phosphorescence is rarely observed in organic molecules, and the modification of its color upon application of physical or chemical stimuli is hardly achieved. In this work, we demonstrate that a decorated persulfurated benzene shows reversible phosphorescence switching in the solid state, as a consequence of conformational changes induced by inclusion of solvent molecules. Quantum-chemical calculations suggest that the luminescence changes are due to emission from triplet states of different character. These results display the close relationship between structural factors and phosphorescence in solid state emitters, representing a valuable benchmark for the design of all-organic luminescent sensors with the desired photophysical properties.