A selective colorimetric chemosensor with an electron-withdrawing group for multi-analytes CN− and F−

Abstract

A new colorimetric chemosensor with an electron-withdrawing group (–NO₂) 1 for the detection of CN⁻ and F⁻ has been simply developed. Receptor 1 showed selectively colorimetric responses to CN⁻ in aqueous solution and F⁻ in acetonitrile, respectively. An obvious color change of 1 from yellow to colorless was observed for CN⁻ through a nucleophilic addition mechanism, while F⁻ was detected through a deprotonating mechanism with a distinct color change from pale yellow to orange. The binding modes of receptor 1 with two analytes (CN⁻ and F⁻) were proposed to be 1 : 1, based on the Job plot, ¹H NMR titration, and ESI-mass spectrometry analysis.