A highly selective ratiometric and colorimetric chemosensor for cyanide detection

•We have synthesized a ratiometric and colorimetric chemosensor for cyanide sensing.•The reaction between the sensor and cyanide caused an apparent color change.•The selectivity of the sensor for cyanide over other anions is extremely high.•The sensor could detect cyanide in 3 min and achieve real-time detection.

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 CN 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.

Graphical abstractA novel ratiometric and colorimetric chemosensor bearing hybrid coumarin-hemicyanine functionality has been synthesized for cyanide sensing via the nucleophilic attack.Figure optionsDownload full-size imageDownload as PowerPoint slide