Spectroscopic and computational studies on the development of simple colorimetric and fluorescent sensors for bioactive anions

Abstract

Spectroscopic techniques (UV–vis and fluorescence) and computational (HF/6-31G(d,p)) methods were adopted to investigate the anion recognition ability of two novel Schiff base receptors (L ¹ and L ² ) synthesised from the condensation of 5-nitrosalicylaldehyde and 2-aminophenol or 2-aminothiophenol. Both the receptors portrayed a visually detectable colour change upon addition of fluoride, acetate and dihydrogen phosphate anions from light yellow (L ¹ ) or colourless (L ² ) to yellow due to the formation of hydrogen bonding complexes in 1:1 stoichiometry and/or deprotonation between these anions and the receptors. No significant colour change was observed upon addition of other anions such as chloride, bromide, iodide and hydrogen sulphate.

Keywords:

• anion recognition
• colorimetric and fluorescent sensors
• Schiff bases
• HF/6-31G(d,p)

Acknowledgements

The authors thank Director, SV National Institute of Technology, Surat, for encouragement and for providing necessary research facilities. This work was made possible by a grant from the DST, New Delhi, under Fast Track Young Scientist Scheme.