A iridium(III) complex-based ‘turn-on’ fluorescent probe with two recognition site for rapid detection of thiophenol and its application in water samples and human serum

Abstract

Abstract A new iridium(Ⅲ) complex-based near-infrared ‘turn-on’ fluorescent probe Ir-DNBS was synthesized for fast (9 min), highly selective and sensitive (LOD: 62.5 nM) thiophenol detection. Photophysical and spectral characterization (NMR, HRMS) results demonstrated that the recognization mechanism of probe for thiophenol was based on thiolate-mediated nucleophilic elimination reaction (SNAr). Upon addition with thiophenol to PBS/DCM/DMSO solution (pH = 7.4) of probe Ir-DNBS, obvious orange red fluorescence with maximum emission wavelength at 620 nm was observed with a large Stokes shift (200 nm) and long lifetime (135 ns). The practical utility of probe Ir-DNBS was also investigated by thiophenol detection in real water samples and human serum.