A highly selective ratiometric and colorimetric chemosensor for cyanide detection

Abstract A novel ratiometric and colorimetric chemosensor bearing hybrid coumarin-hemicyanine functionality has been synthesized for cyanide sensing. The detection of cyanide was performed via the nucleophilic attack of cyanide anion toward the polarized C N bond of the hybrid coumarin-hemicyanine dye. The reaction between the sensor and cyanide anion caused a remarkable decrease in the absorption spectra at 510 nm and simultaneously yielded a clear color change from red to yellow due to the blocking of the π-conjugation between hemicyanine and coumarin. The ratiometric absorbance changes showed a linear response to cyanide anion in the concentration range of 9.8–2000.0 μM. The sensor achieved rapid detection of cyanide anion in 3 min and possessed high selectivity for cyanide with respect to other common anions. In addition, the sensor can serve as practical colorimetric sensor for “in-the-field” measurement that would not require any additional equipment by virtue of a “dip-stick” approach.