Polymorphism-Dependent Room-Temperature Phosphorescence of a Persulfurated Benzene

Abstract

Persulfurated benzenes are among the most efficient phosphorescent organic materials in the solid state at room temperature. Correlating their structural, conformational and crystalline behavior with their photophysical properties is of prime importance. Here, we investigate the crystallization of compound A6-iPr in two polymorphs (forms I and II) that display significant differences in their photophysical properties. Both forms emit by Room-Temperature Phosphorescence (RTP) with different colors, as a consequence of the different conformations adopted in the crystal lattice. Quantum chemical calculations rationalize the crucial role of conformations and intermolecular interactions in defining the nature of the emissive triplet state.