Design and Synthesis of a Fluorescent Probe with a Large Stokes Shift for Detecting Thiophenols and Its Application in Water Samples and Living Cells.

Shuju Guo,Hua Liu,Dayong Shi,Chuanlong Guo,Lijun Wang

doi:10.3390/molecules24020375

Abstract

A turn-on florescent probe (probe-KCP) was developed for highly selective detection of thiophenols based on a donor-excited photo-induced electron transfer mechanism. Herein, the synthesis of the probe, a chalcone derivative, through a simple straightforward combination of a carbazole-chalcone fluorophore with a 2,4-dinitrophenyl functional group. In a kinetic study of the probe-KCP for thiophenols, the probe displayed a short response time (~30 min) and significant fluorescence enhancement. In selection and competition experiments, the probe-KCP exhibited excellent selectivity for thiophenols over glutathione (GSH), cysteine (Cys), sodium hydrosulfide (NaSH), and ethanethiol (C2H5SH) in addition to common anions and metal ions. Using the designed probe, we successfully monitored and quantified thiophenols, which are highly toxic. This turn-on fluorescence probe features a remarkably large Stokes shift (130 nm) and a short response time (30 min), and it is highly selective and sensitive (~160-fold) in the detection of thiophenols, with marked fluorescence in the presence of thiophenols. probe-KCP responds to thiophenols with a good range of linearity (0–15 μM) and a detection limit of 28 nM (R2 = 0.9946) over other tested species mentioned including aliphatic thiols, thiophenol analogues, common anions, and metal ions. The potential applications of this carbazole-chalcone fluorescent probe was successfully used to determine of thiophenols in real water samples and living cells with good performance and low cytotoxicity. Therefore, this probe has great potential application in environment and biological samples.

Highlights

Thiophenols are small molecules that serve as essential raw materials in the synthetic chemical industry
The synthesis procedure of the target chalcone fluorescent probe-KCP for the detection of thiophenols is outlined in Scheme 1
The probe-KCP was synthesized with chalcones as a strong fluorophore linked to a 2,4-dinitrophenyl group acted simultaneously as recognition unit and a fluorophore quencher

Summary

Introduction

Thiophenols are small molecules that serve as essential raw materials in the synthetic chemical industry. Thiophenols are pollutants which are highly toxic to Molecules 2019, 24, 375; doi:10.3390/molecules24020375 www.mdpi.com/journal/molecules. Molecules 2019, 24, 375 organisms, including humans, where thiophenol toxicity can have adverse physiological and psychological effects. Prolonged exposure to thiophenols can cause damage to the central nervous system, breathing difficulties, muscle weakness, paralysis of the limbs, a coma, and even death [3,4]. Previous research reported that the median lethal dose of thiophenols to fish and mice was. Thiophenols are considered a priority pollutant by the U.S Environmental Protection Agency (EPA waste code: P014) [5,6]. There is an urgent need for the development of a rapid, selective, and sensitive method for monitoring of thiophenols in environmental samples and biological samples

Methods

Results

Conclusion