Dual quenching strategy for sensitive detection of toxic thiolphenols based on a NIR-illuminant platform with a large Stokes shift

In view of thiophenol contaminants and their adverse effects in environment, it is valuable to develop an effective probe for thiophenols. Based on a large Stokes shift (126 nm) NIR-illuminant platform (Compound 2), we developed a colorimetric and off-on near-infrared (NIR) fluorescent probe (NIRP) to selectively discriminate thiophenols from various analytes including aliphatic thiols. NIRP is dually quenched (ICT blocked quenching and PET quenching), thus achieving large signal-to-noise ratio and high sensitivity for thiophenol detection. For the first time, the unique NIR-illuminant phenomenon of 2' and the d-PET quenching process on NIRP are revealed by the density functional theory (DFT) calculations. Moreover, we demonstrate the practical applications of NIRP, including the quantitative thiophenol detection in environmental water samples and NIR fluorescent imaging of thiophenol in HeLa cells.