New Insights into the Recognition and Sensing Mechanism of a H 2 S Fluorescent Probe: A Theoretical Perspective.

H 2 S is an important signal molecule in living systems and related with many physiological processes and diseases. Rapid detection of H 2 S, hence, is important for studying physiological processes and early diagnosis of diseases. Deep insight into the sensing mechanism is significant and inspiring for the design and modification of high-efficiency H 2 S probes. The current study has theoretically investigated the recognition and fluorescence mechanism of a newly reported high-efficiency H 2 S probe. The recognition mechanism is determined to be the reaction between the probe and HS - anion, the rationality of which is further confirmed from the fluorescence property of the recognition product. The non-fluorescence property of the probe attributes to a photoinduced electron transfer process, and the turn-on fluorescence upon exposure to H 2 S exhibits an intramolecular charge transfer property according to frontier molecular orbital analysis.