A series of 8-hydroxyl-5-(4-substituted phenylazo) quinoline derivatives were designed and synthesized.The interactions between receptors and anions such as F^-, AcO^-, H₂PO₄^-, Cl^- and Br^- in acetonitrile were investigated by UV-vis spectroscopy.Results indicated that hydrogen-bonding complexes were formed between receptors and anions, which induced remarkable color change.It was found that the selectivity of receptors to anion could be efficiently tuned by substitution at the phenyl moiety.Receptor 1, 8-hydroxyl-5-(4-methylphenylazo) quinoline, was capable of selectively binding fluoride anion over other anions.A 1:1 model complex was formed between 1 and fluoride, the solution of 1 turned red from colorless and a new absorption band peaked at 508 nm appeared.The association constant of 1-F^- complex was 2.5×10 4 mol^-1·L.However, no obvious color changes were observed on addition of equivalent of other anions such as AcO^-, H₂PO₄^-, Cl^- and Br^-.A selective colorimetric assay for fluoride was developed.

Key words: anion recognition, 8-hydroxyl-5-(4-substituted phenylazo)quinoline derivative, colorimetric assay