A facile synthesis of amide-based receptors under microwave conditions: investigation of their anion recognition properties by experimental and computational tools.

Two novel amide-based receptors were synthesized under microwave irradiation. Their chemical structures were confirmed by IR, 1H NMR, 13C NMR, and elemental analysis. The binding properties of these amide-based receptors to various anions (H2PO4-, HSO4-, C6H5CO2-, CH3CO2-, ClO4-, F-, Cl-, and Br-) were examined by UV titration in THF at 20 °C. The results indicated that the receptors form 1:1 complexes with anions and they have the strongest affinity for fluoride (F-) among the anions considered. Molecular dynamics calculations by AMBER and quantum mechanical calculations performed at the B3LYP and M062X levels of theory using the 6-31 + g(d,p) basis set provided models for the complexation mode between the receptors and anions and yielded binding energies for the complexes. Graphical abstract The computed interaction mode of tripodals (1a and 1b) with fluoride.