A Sensitive and Selective Fluorescent Thiol Probe in Water Based on the Conjugate 1,4‐Addition of Thiols to α,β‐Unsaturated Ketones

Abstract

Shedding light on thiol detection: A compound (see scheme) was developed as a novel, highly sensitive and selective fluorescent thiol probe, which also features suitable water solubility, functions rapidly under neutral conditions, and has excitation and emission in the visible region. Thus, it may be useful for potential biological applications. Compound 1 was designed and synthesized as a new fluorescent thiol probe. Probe 1 was constructed on the basis of the conjugate 1,4-addition of thiols to α,β-unsaturated ketones. Notably, probe 1 has suitable water solubility, which allows the sensing assay to be performed in water. Probe 1 is highly sensitive for thiols with a 211-fold fluorescence dynamic range and a low detection limit of 9.25×10⁻⁷ M. The major features of probe 1 also include a high selectivity for thiols over other relevant biological species, excitation and emission in the visible region, rapid functioning at pH 7.4, and a good linear relationship between the fluorescence signal and the thiol concentration. Accordingly, these desirable characteristics may render probe 1 as potentially useful for biological applications.