Electrochemical sensing of 4-nitrophenol through heteroleptic complexes of Ag(I) and Hg(II) based on 2-thiazoline-2-thiol: Synthesis, crystal structures, and Hirshfeld analysis

Abstract

In pursuit of a more effective electro-sensor for environmentally hazardous nitro phenols detection at the trace level, we have developed two novel complexes [Ag(μ-S-thzt)(Hthzt)(PPh3)]2·2CH3CH2OH (1) and [Hg (thzt)2(o-phen)](2) based on 2-thiazoline-2-thiol (Hthzt). In complexes 1 and 2, triphenylphosphine and o-phen were used as co-ligands, respectively. Both the synthesizedcomplexes have been characterized by single crystal X-ray diffraction data,UV–vis., infrared, and NMR spectrometry. Geometry around both the metal ion complexes is distorted tetrahedral. Noticeably, in complex 1, the Hthzt acts as a bridging as well as terminal ligand. The intermolecular interaction found in complexes 1 and 2 have been further investigated through Hirshfeld surface analysis. On comparing fluorescence intensities of Hthzt, complex 1, and complex 2, the order of fluorescence behavior was found to be Hthzt > complex 1 > complex 2. The electrochemical performance of both complexes 1 and 2 and their ability to sense 4-nitrophenol (NP) have been evaluated through modified glassy carbon electrodes and were detected by the differential pulse voltammetry (DPV) and cyclic voltammetry (CV) methods. Based on electrochemical responses, complex 1 shows more effective performance as anelectro-sensor than complex 2. With a relatively low detection limit of 0.19 μM, great selectivity, and acceptable sensitivity, the complex 1/GCE sensor demonstrated an exceptional linear plot between the oxidation peak current and NP concentration in the ranges of 0.5–500 μM. © 2023 John Wiley & Sons Ltd.