Sulfone-functionalized Stereoisomeric [3]Radialene Displays Guest-induced Modulation of Porous Frameworks and Critical Crystallization-induced Near-infrared Emission

Abstract

Luminescence-responsive porous organic materials have garnered significant interest due to their chemical versatility, adaptability and potential applications in smart sensors and optoelectronic devices. In this study, we introduce a novel class of sulfone-functionalized stereoisomeric [3]Radialene TTRO with quasi-C₃ symmetry, which demonstrates flexible structural configurations and the ability to form diverse crystalline frameworks with tunable porosity ranging from 0% to 31.2%. These assembled frameworks are characterized by distinct stereochemical configurations of TTRO, which influence their dipole moment vectors and molecular packing parameters, especially the geometry of the exo-cyclic radialene ring. The stability of these structures is further enhanced by sulfone-embedded aromatics and guest solvent molecules, establishing a network of multivalent molecular interactions. Remarkably, TTRO-based materials exhibit crystallization-induced emission in the near-infrared (NIR) region (650–1000 nm), transitioning from non-emissive amorphous powders to strong photoluminescence (up to 24.1%) in guest-involved porous crystalline frameworks. Time-resolved fluorescence and computational analyses reveal that the dynamic stacking geometry of TTRO units, combined with multivalent sulfone-based intermolecular interactions with guest molecules, modulates the reorganization energy within the frameworks, thereby tuning solid-state emission. These findings provide new insights and strategies for designing NIR luminophores through crystalline engineering of [3]radialene materials