Colorimetric sensing of cyanide and fluoride ions by diaminomalenonitrile based Schiff bases

Two new diaminomalenonitrile (DMN) based Schiff bases have been synthesized and explored as a highly efficient receptor for fluoride and cyanide anions. Detection of anions induced by deprotonation of-NH2 followed by transfer of proton to the electron deficient nitrogen atom of -CN which induce the strong charge transfer (CT). Anion selectivity was controlled by the fluorophore attached to the DMN, the fluorophore can tune the electron push-pull property. This phenomenon was confirmed by H-1 NMR and DFT calculations. (C) 2017 Elsevier B.V. All rights reserved.