A selective quinoline-derived fluorescent chemodosimeter to detect cyanide in aqueous medium

A simple quinoline derived probe 3 has been described. Probe 3 having aldehyde function upon interaction with cyanide undergo nucleophilic addition reaction to form cyanohydrin derivative 4 in which fluorescence intensity enhances significantly, 'turn-on' by photoinduced electron transfer (PET) OFF-ON mechanism. The color of probe solution switched-on to fluorescent blue which is visible to the naked-eye. Job's plot analysis revealed a 1:1 stoichiometry for an interaction between 3 and cyanide along with detection limit 0.058 μM (1.5 ppb). The mode of interaction to detect cyanide in aqueous medium through a reaction based chemodosimeter approach has been confirmed by NMR, mass, FTIR, and DFT data analysis.