Highly selective reaction based colorimetric and fluorometric chemosensors for cyanide detection via ICT off in aqueous solution

[Display omitted] •Developed thiazole functionalized receptors to sense CN− ions.•Probes showed dramatic color change from wine red/purple to colorless.•The detection limits were calculated to be 3.6 and 4.2 μM.•The binding stoichiometry was found a 1:1 using mass analysis.•The test strips were fabricated for on-site detection of CN− ion in aqueous solution. In the present work, thiazole functionalized receptors, S1 and S2, containing aminophenol as a signaling unit have been prepared and evaluated by UV–vis and fluorescence methods. These receptors consisting of conjugated benzothiazol-aminophenol system, which exhibited rapid and selective response towards cyanide anion. These two probes showed dramatic color change from wine red/purple to colorless, and optical quenching was also observed upon addition of CN− ions based on intramolecular charge transfer (ICT) transition in aqueous media. The detection limit of the probe S1 and S2 for CN− was calculated as 3.6 and 4.2 μM by spectrophotometric, 0.5 and 0.6 μM by spectrofluorophotometric methods, respectively. The binding stoichiometry between probes and cyanide was found to be 1:1, and the binding mechanism was also proposed.