Highly selective near-infrared fluorescent probe with large Stokes shift and sensitivity for H2S detection in water, foodstuff and imaging in living cells

Hydrogen sulfide (H2S) is an endogenous gas signaling molecule that plays an indispensable role in human physiological processes and is of great significance for sensitivity detection in environmental and foodstuff applications. Herein, a novel near-infrared (NIR) fluorescent probe based on 4-(5-(7-(thiophen-2-yl)benzo[c] [1,2,5]thiadiazol-4-yl)thiophen-2-yl)phenol) (D-A-D structure) and 2,4-dinitrobenzenesulfonyl chloride were successfully synthesized. The fluorescent probe 4-(5-(7-(thiophen-2-yl)benzo[c] [1,2,5]thiadiazol-4-yl)thiophen2-yl)phenyl 2,4-dinitrobenzenesulfonate (TTPD) could selectively response to H2S by releasing a D-A-D group as fluorescence enhancing system, which performed NIR "turn-on" fluorescence (652 nm) in acetonitrile solution, triggering by the cleavage of sulfonamide group. The fluorescent probe detected H2S with the excellent characteristics of fluorescence intensity emission change, high selectivity, outstanding anti-interference performance, large Stokes shift (192 nm), and low limit of detection (LOD) (LOD = 62.1 nM). What's more, this probe not only served as a tool for monitoring H2S in food quality and diverse water samples with good recovery rates, but also it showed low toxicity and an outstanding capability in cell imaging.