Synthesis and spectral characterization of the phenothiazine-thiosemicarbazide probe for the optical solid-state detection of Hg 2+ and Cu 2 .

In this study, a phenothiazine-thiosemicarbazide (PTZDS) probe was synthesized and characterized. The synthesized PTZDS probe exhibited a yellow color, with a native fluorescence emission at λ emission = 550 nm and λ excitation = 450 nm. Over other metal ions, the probe exhibited significant selectivity and sensitivity towards Hg 2+ and Cu 2+ . The probe showed fluorescence quenching along with a minor shift in the absorbance spectra from 400 to 450 nm and 430 nm in the presence of Hg 2+ and Cu 2+ , respectively. In addition, the color of the synthesized probe remarkedly faded with the addition of Hg 2+ or Cu 2+ . Fluorescence measurements, infrared spectroscopy (IR), and density functional theory studies were employed to elucidate the binding process in the PTZDS + Cu 2+ and PTZDS + Hg 2+ sensor systems. Furthermore, photophysical investigations of the synthesized probe with Hg 2+ and Cu 2+ were performed. Finally, the probe was successfully employed as a solid-state thin layer chromatography (TLC) optical sensor for detecting Hg 2+ and Cu 2+ ions.