A naphtholic Schiff base for highly selective sensing of cyanide via different channels in aqueous solution

•A 2-hydroxynaphthaldehyde-aminobenzimidazole Schiff base sensor shows both colorimetric and fluorescence response for CN−.•The sensor was designed with ease of synthesis and low cost.•The sensor has good selectivity to CN− even in the presence of other anions.•Test strips of the sensor were fabricated and exhibited a selectivity to CN−.

A simple CN− sensor bearing a naphthol and an imine group was designed and synthesized, which showed both a colorimetric and a fluorescence turn-on response for cyanide ions in aqueous solution. The probe shows an immediate visible change in color from yellow to orange which then becomes colorless followed by a final change to pink, when cyanide is added; these color changes can be readily observed visually. The mechanism of the reaction of the probe with the cyanide ion was established by using 1H NMR and FT-IR spectroscopy and mass spectrometry. Moreover, test strips based on the sensor were fabricated, which could act as a convenient and efficient CN− test kit.

Graphical abstractA simple CN− sensor bearing a naphthol and an imine group was designed and synthesized, which showed both a colorimetric and a fluorescence turn-on response for cyanide ions in aqueous solution.Figure optionsDownload full-size imageDownload as PowerPoint slide