Hg²⁺ induced hydrolysis of thiazole amine based Schiff base: Colorimetric and fluorogenic chemodosimeter for Hg²⁺ ions in an aqueous medium

Simple pyrene-based chemosensors 1 to 3, were synthesized from pyrene-1-carboxaldehyde and they were characterized using various spectroscopic techniques like UV-Vis, FT-IR, Mass, ¹H NMR and ¹³C NMR. Among synthesized receptors, the receptor 1 shows high selectivity towards Hg²⁺ ions. Further, the high selectivity of receptor 1 towards Hg²⁺ ions in the presence of various other interfering metal ions like Ni²⁺, Zn²⁺, Mn²⁺, Co²⁺, Cu²⁺, Cr³⁺, Fe³⁺, Al³⁺, Ag⁺, Fe²⁺, Cd²⁺, Mg²⁺, Pb²⁺, Ca²⁺, Na⁺, K⁺ was confirmed by UV-Vis and fluorescence methods. The detection limit for Hg²⁺ ions was found to be 0.270 μM. The chemodosimetric irreversible hydrolysis of the receptor 1 in the presence of Hg²⁺ was studied by UV/Vis, fluorescence, FT-IR, LC-MS, ¹H NMR and theoretical DFT study. Further, the real life applications of receptor 1 for the determination of Hg²⁺ ions were demonstrated by UV-Vis method.