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.