Ratiometric fluorescent probe for highly selective detection of gaseous H2Se

H2Se has been widely applied, and its release will cause serious human health and environmental effects. It is urgent to develop facile tool and reliable method for the determination of H2Se. Here, we introduce a concisely synthesized molecular HBT-Se, with a specially designed H2Se trapper 2-(iodomethyl)benzoate and a typical ESIPT fluorophore. The free HBT-Se exhibited blue fluorescence owing to the blocked ESIPT (exited state intramolecular proton transfer) process, while the 2-(iodomethyl)benzoate group could undergo a cascade reaction with H2Se, unblocking the ESIPT process and bathochromically shifting fluorescence response. The sensing mechanism was also rigorously verified by H-1, Se-77 NMR and MS analyses. Additionally, HBT-Se features a sensitive, selective and quantitative determination of H2Se. With these satisfied properties, HBT-Se was further applied as a paper-based sensor for detection of gaseous H2Se, and the enhanced performances of HBT-Se will promote its potential value in further study of H2Se in environmental pollutant.