Curcumin based supramolecular ensemble for optical detection of Cu2+ and Hg2+ ions

A novel curcumin based molecular probe L1 was synthesized using 2-aminothiazole through covalent linkage. The structure of the probe L1 was characterized by UV-Vis, Fluorescence, SEM, PXRD and other related spectroscopic techniques. The molecular probe L1 was screened over assorted metal ion and selectivity was observed with Cu2+ and Hg2+ ion through the change of color in aqueous medium which was confirmed by UV or fluorescence signal and also supported by SEM and PXRD results. An unusual value of LOD with Cu2+ and Hg2+ ion was calculated to be 2.0 mu M and 1.2 mu M, respectively, which confirmed the selectivity of L1. The quenching in fluorescence spectrum was observed only with Cu2+ and Hg2+ ion, due to the loss of energy. The complex formation between L1 and Cu2+/Hg2+ ions were further studied by density functional theory using B3LYP/6-31(G) method to support the experimental results. Time-dependent-DFT studies were performed with LANL2DZ basis set to study the accurate complex mechanism which indicated a large HOMO-LUMO gap with Hg2+ ions. (C) 2020 Elsevier B.V. All rights reserved.