A sensitive PET "turn on" fluorescent probe for specific detection of 4-methoxy-thiophenol.

• In this paper, we report a 1,8-naphthalimide/ triphenylamine-based fluorescent probe (TPA-NI-NO 2) for the specific detection of 4‑methoxy-thiophenol (MTP) with good selectivity among the thiophenols. • The probe can "turn on" detect MTP with the limit of detection (LOD) of 80 nM and no obvious response to relevant analytes and homologues. • The sensing mechanism was explored by HPLC experiment and the PET process was determined by density functional theory (DFT) calculations. • The Gibbs free energy (DG) analysis for the reaction between the probe and different thiophenols were obtained by the theoretical calculations to study the specificity of the probe. • The probe was successfully applied to monitor the MTP in Hela cells. Thiophenols as a series of industrial products are widely used and high toxicity to the organisms and the environment. The fluorescent probe technique offers important insights into thiophenols convenient sensing. Herein, we report a 1,8-naphthalimide/ triphenylamine-based fluorescent probe (TPA-NI-NO 2) for the specific detection of 4‑methoxy-thiophenol (MTP). The probe can "turn on" specific detect MTP with the limit of detection (LOD) of 80 nM among various relevant analytes and homologues (p -Cl-C 6 H 4 SH, p -NO 2 - C 6 H 4 SH, C 6 H 5 SH and o -CH 3 - C 6 H 5 SH). The sensing mechanism was explored by the HPLC experiment and the PET process was determined by density functional theory (DFT) calculations. In addition, the specificity of the probe was also studied by the Gibbs free energy (ΔG) analysis of the reaction between the probe and different thiophenols. The reaction between probe and MTP gives the minimum of the ΔG value (∼ -9.7280 kcal/mol) and that of other thiophenols-mediated is -2.5283 to -5.8911 kcal/mol, which proves the thermodynamic chemical equilibrium can optimize the design of reaction-based fluorescent probes with excellent specificity. At last, TPA-NI-NO 2 was successfully applied to Hela cells imaging. [Display omitted] [ABSTRACT FROM AUTHOR]