Mannich Base Based (β-Amino Carbonyl Compound) Receptor for Efficient and Selective Sensing of Fluoride Ions

Mannich Base (MB) based (β-Amino carbonyl compound) (4) was synthesized by adopting one pot Mannich reaction by taking 3,4-dihydroxybenzaldehyde, aniline and acetophenone as starting materials and the product was characterized using analytical techniques such as FT-IR, NMR, mass spectrometry, UV-Visible spectroscopy. The compound 4 utilized as colorimetric sensor for selective sensing of F^- ions. The particular sensing of F^- is obviously noticeable to the naked eye with a dissimilar colour variation. The F^- detection mechanism has been examined by UV-visible and ¹H NMR titration experimentations. The ¹H NMR titration data describes the deprotonation of OH and N-H protons by F^- as a noticeable stage in the detection. Furthermore, the studies was also carried out for reproduction of deprotonated 4 using trifluoroacetic acid as protonating agent. In addition, Boolean logic gates were fabricated for demonstrating the fluoride sensing mechanism and compound 4 in methyl cellulose biofilm was also been made and effectively used for film based detection of fluoride ion.