Simple NIR-Emitting ESIPT Fluorescent Probe for Thiophenol with a Remarkable Stokes Shift and Its Application

[Image: see text] Thiophenol as a highly toxic compound can harm the environment and living organisms and thus demands effective detection. In this work, we presented a near-infrared fluorescent probe (DAPH-DNP) for detecting thiophenol according to the ESIPT mechanism using 2,4-dinitrophenyl group as a recognition unit. This probe displayed specificity toward thiophenol over other related analytes. Meanwhile, there was good linearity between the relative fluorescence intensity of DAPH-DNP and the concentration of thiophenol in the range of 0–80 μM. This probe also showed a low detection limit of 3.8 × 10(–8) and a marked Stokes shift (192 nm). Further, this probe could be used for monitoring thiophenol in environmental water samples and imaging thiophenol in living cells, which indicated that this probe had a real application in the environment and living organisms.