Novel nitro-substituted formazan derivatives: selective ratiometric and colorimetric chemosensors for fluoride anion sensing detectable by the naked eye

Turkoglu G.

NEW JOURNAL OF CHEMISTRY, vol.44, no.22, pp.9485-9492, 2020 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 44 Issue: 22
  • Publication Date: 2020
  • Doi Number: 10.1039/d0nj01860k
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Biotechnology Research Abstracts, Chimica, EMBASE, DIALNET, Index Chemicus (IC)
  • Page Numbers: pp.9485-9492
  • Anadolu University Affiliated: Yes


Two novel formazan derivatives, FNB and FDNB, were synthesized from the corresponding phenylhydrazones and characterized by various spectroscopic methods. The sensing ability of these formazan sensors towards different anions was determined in THF by a colorimetric UV-vis spectroscopy method. FNB had an efficient colorimetric sensing ability for fluoride anions by changing colour from red to green then blue with a Delta lambda shift of ca. 138 nm, whilst FDNB acted as a colorimetric sensor by changing colour from yellow to red with a Delta lambda shift of ca. 95 nm, which could be recognised by the naked eye. The detection limit of sensor FNB was found to be 0.051 ppm (under the WHO permitted level) in the presence of F- anions. Moreover, the binding forms of F- with the sensors were examined by H-1 NMR experiments. These results indicated that sensors FNB and FDNB, containing nitro groups and hydrazo unit (-NH) hydrogen bond donation, exhibited high sensitivity and selectivity toward fluoride, which has biological importance.