Significant energy gap modulation of sulfone-substituted benzosiloles: enhanced brightness and electron affinity for chemical vapor sensing, fingerprint detection and live-cell imaging

Abstract

A series of novel sulfone-modified benzosilole and dithienobenzosilole luminogens were synthesized via straightforward chemical oxidation of the corresponding methylthio or thiophene precursors. The intrinsic photophysical properties, photo-stability and thermal stability of these luminogens were systematically studied by UV-vis and fluorescence spectroscopy assisted with theoretical calculations. High thermal stability and remarkable photo-stability have been demonstrated and mainly attributed to the benzosilole core, while the negative inductive effect originating from sulfone groups endows them with strong electron affinity. With significant modulated energy gaps, these compounds exhibit a broad range of fluorescence colors from blue to orange red and high brightness as well as extremely high quantum yields up to 99% in solution and the solid state due to the competition between the localized excited and charge transfer electron transitions. The intriguing photophysical characteristics enabled them to be applied in reversible acid-base chemical vapor detection, latent fingerprints, and live-cell imaging.