Coumarin–hemicyanine conjugates as novel reaction-based sensors for cyanide detection: convenient synthesis and ICT mechanism

Abstract

Using intramolecular charge transfer (ICT) as a signaling mechanism, a series of hybrid coumarin–hemicyanine compounds were synthesized as chemosensors for cyanide detection by taking advantage of cyanide's strong affinity toward the polarized CN bond of the hemicyanine group. Structure identification of the compounds was confirmed by ¹H NMR, ¹³C NMR, ¹H-¹H COSY, HSQC, IR, and HRMS spectroscopy. Multiple sensory signals are available and can be used for both qualitative monitoring and quantitative determination of cyanide, including high-contrast visual color change, fluorescence quenching and enhancement.