Study on Synthesis and Binding Ability of a New Anion Receptor Containing NH Binding Sites

A new colorimetric recognition receptor 1 based on the dual capability containing NH binding sites of selectively sensing anionic guest species has been synthesized. Compared with other halide anions, its UV/Vis absorption spectrum in dimethyl sulfoxide showed the response toward the presence of fluoride anion with high selectivity, and also displayed dramatic color changes from colorless to yellow in the presence of TBAF (5×10⁻⁵ mol/L). The similar UV/Vis absorption spectrum change also occurred when 1 was treated with AcO⁻ while a little change with H₂PO⁻₄ and OH⁻. Receptor 1 has almost not affinity abilities to Cl⁻, Br⁻ and I⁻. The binding ability of receptor 1 to fluoride with high selectivity over other halides contributes to the anion size and the ability of forming hydrogen bonding. While the different ability of binding with geometrically triangular (AcO⁻), tetrahedral (H₂PO⁻₄) and linear (OH⁻) anions maybe result from their geometry configuration.