A novel flavone-based ESIPT ratiometric fluorescent probe for selective sensing and imaging of hydrogen polysulfides.

[Display omitted] • A simple flavone-based chemosensor was synthesized based on ESIPT process for ratiometric detection of hydrogen polysulfides. • The probe displayed high selective and sensitive for hydrogen polysulfides (detection limit is 0.63 μM). • The probe was successfully applied to exogenous H 2 S n detection and imaging by dual emission channels in living Hela cells. Hydrogen polysulfides (H 2 S n) as an important member of reactive sulfur species is closely relevant to many physiological functions in redox homeostasis and metabolism. Dual-channel monitor the changes of H 2 S n level in vivo is highly desired. Herein we design a simple ratiometric fluorescent probe based on flavone skeleton for highly selective detection of H 2 S n. The probe HF-NA-MC bearing 2-fluoro-5-nitrobenzoic acid group inhibited the intramolecular ESIPT process, which show the blue fluorescence of adjacent naphthalene unit. In the presence of H 2 S n , the enol form of probe is converted to conjugated keto form, resulted in a 90 nm red-shift of fluorescence emission from 450 nm to 540 nm. The ratiometric intensity (I 540 /I 450) of the probe exhibits a good linear relationship toward H 2 S n in the range of 0–120 μM, and the detection limit is estimated to be 0.63 μM. The ratiometric fluorescent probe shows high specificity and anti-interference ability for H 2 S n over other related reactive sulfur species. The probe HF-NA-MC shows promising outlook and could be applied to the confocal imaging of H 2 S n by dual emission channels in Hela cells. [ABSTRACT FROM AUTHOR]