An aggregation-induced fluorescence probe for H2S and its application in living cells

Hydrogen sulphide (H₂S) plays an important role in the regulation of a number of important physiological and pathological processes. Therefore, the development of new fluorescent probes for H₂S is of great importance and has recently attracted much attention. In this paper, a novel coumarin-based fluorescent probe named (1E)-1-(1-(6-chloro-2-oxo-2H-chromen-3-yl)ethylidene)thiosemicarbazide (1), which contained a CN moiety as a specific reaction site for nucleophilic addition of H₂S, was prepared. Upon addition of H₂S, probe 1 exhibited significant fluorescence enhancement with a detection limit as low as 0.54 μM, accompanied by a colour change from cyan to colourless. The mechanism was confirmed by ESI-MS, Job’s plot, DFT and the probe 1 was successfully applied to the imaging of H₂S in HeLa cells.