A ratiometric fluorescent probe for gasotransmitter hydrogen sulfide based on a coumarin-benzopyrylium platform

A ratiometric fluorescent probe for H2S was developed based on a coumarin- benzopyrylium platform. The ratiometric sensing is realized by a selective conversion of acyl azide to the corresponding amide, which subsequently undergoes an intramolecular spirocyclization to alter the large π-conjugated system of CB fluorophore. Compared with the traditional azide-based H2S probes, the proposed probe utilizes the acyl azide as the recognition moiety and exhibits a rapid response (∼1min) towards H2S, which is superior to most of the azide-based H2S probes. Preliminary fluorescence imaging experiments show that probe 1 has potential to track H2S in living cells.