Synthesis of chromone-based thiosemicarbazone as selective chemosensor for cyanide ion and its DFT calculation studies

Chemosensors, for the recognition of anions have gained great attention in the field of supramolecular chemistry. Novel chromone-based colorimetric chemosensors, SN-1 and SN-2 are reported for the detection of F− and CN− ions. The structural characterization was done by1H-NMR, 13C-NMR, and UV-Vis spectroscopy. Colorimetric properties of the chemosensors were investigated in presence of different species (F−, AcO−, Br−, ClO−4, Cl−, HSO4−, I−, SCN−, and CN−). The chemosensors SN-1 and SN-2 displayed high selectivity towards CN− and F− ions. The limits of detection for SN-1 and SN-2 were found to be 5.5 × 10−8 and 3.3 × 10−8 for the CN− ion respectively. Chemosensor SN-2 showed greater response towards F− ion with low limit of detection 2.8 × 10−8 and its binding constant was assessed to be 2.5 × 104. The chemosensors could be used to detect the F− ion in real samples of toothpaste and in test strips. Density functional theory (DFT) study supported our experimental findings.</p