Naked-eye detection of F− and AcO− ions by Schiff base receptor

A Schiff base 2, composed with o-phenylenediamine and 5-nitro-salicylaldehyde have been synthesized as an anion receptor. It consists with conjugated imine, phenolic –OH and electron withdrawing substituent nitro (–NO2) group. Receptor 2 can recognize selectively biologically important F− and AcO− ions. The recognition properties have been investigated by naked-eye color change (colorless to yellow), followed by UV–vis spectral changes. Predicted stoichiometries of the complexes between receptor 2 and anions based on density functional theory (DFT) level calculations, corroborates well with experimental findings.