Novel indole based dual responsive “turn-on” chemosensor for fluoride ion detection

• The receptor DN was synthesized by a simple method with high yield.
• The detection limit of F− by DN was very low (2.73 × 10−7 M).
• The reversible behavior of the receptor DN towards F− was studied.
• The remarkable red shift fluorescence spectra was further supported by DFT calculations.

An efficient new dual channel chemosensor 2,3-bis((E)-(1H-indole-3-yl)methyleneamino)maleonitrile (DN) which exhibits selective sensing of F− ions in DMSO, was synthesized by a facile one step condensation reaction of indole-3-carboxaldehyde with diaminomaleonitrile. The probe DN was characterized by elemental analysis, 1H, 13C-NMR, ESI-MS and IR spectral techniques. Upon addition of F−, DN induces remarkable changes in both absorption and fluorescence spectra on the basis of charge transfer mechanism. The receptor DN serves for highly selective, sensitive detection of F− without the interference of other relevant anions. The Job’s plot analysis indicates the binding stoichiometry to be 1:1 (host/guest).

Figure optionsDownload as PowerPoint slide