Colorimetric and fluorimetric detection of CN- ion using a highly selective and sensitive chemosensor derived from coumarin-hydrazone

Novel chemosensors, including coumarin hydrazide, were designed and synthesized by a three-step synthesis sequence starting from 7-(diethylamino)-2-oxo-2H-chromene-3-carbohydrazide. General spectroscopic methods (FT-IR, 1H/13C NMR, and HRMS) were used to characterize all produced chemosensors. These chemosensors demonstrate the ability to detect cyanide (CN-) anion by shifting absorption and fluorescence turn-off response in DMSO. The reaction mechanism between the synthesized chemosensors and the CN- anion involves deproto-nation and addition processes; as determined by dipole-dipole interactions, reversibility, 1H NMR experiments, and theoretical studies. With limit of detection (LOD) values of 0.25 mu M and 0.15 mu M for 3a and 3b, respectively, these chemosensors exhibit exceptional detection ability and demonstrate the high effectiveness of their use for CN- anion determination.