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

- We have synthesized and characterized two different diaminomalenonitrile based Schiff bases.
- Both the molecules act as efficient colorimetric sensor for fluoride and cyanide anions.
- The detection of anions induced by deprotonation and followed charge transfer (CT) transition red shifted with a fluorescence 'turn-on'.
- Anion selectivity was controlled by the fluorophore attached to the DMN, the fluorophore can tune the electron push-pull property.

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 1H NMR and DFT calculations.

We have successfully synthesized and characterized two different new diaminomalenonitrile based Schiff bases. Both the molecules act as an efficient colorimetric sensor for fluoride and cyanide anions. The detection of anions induced by deprotonation and the following charge transfer (CT) transition red shifted with a fluorescence 'turn-on'. 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 1H NMR and DFT calculations.65