A C3-symmetric colorimetric anion sensor bearing hydrazone groups as binding sites

Tris–hydrazone (1) functioned as a colorimetric chemosensor for a variety of anions such as F−, AcO− and H2PO4−. The anion binding could be easily detected by naked-eye according to color changes. The high binding ability of the receptor 1 to anions was further investigated by UV–vis absorption spectroscopy in DMSO. The results of job plot of the receptor 1 with different anions demonstrated that the stoichiometry of the complex between 1 and F− was 1:1 (1:anion) and the stoichiometry of the other complexes studied was 1:3 (1:anion).