A highly selective naked-eye colorimetric sensor for acetate ion based on 1,10-phenanthroline-2,9-dicarboxyaldehyde-di-(p-substitutedphenyl-hydrazone)

A new and simple colorimetric sensor with high selectivity for acetate ion based on 1,10-phenanthroline-2,9-dicarboxyaldehyde-di-(p-substitutedphenylhydrazone) receptor 2 has been synthesized. The selectively binding ability of receptor 2 to acetate ion over other anions tested was demonstrated by UV–vis absorption spectroscopy in DMSO. Comparing with other anions studied, the UV–vis absorption spectrum in dimethyl sulfoxide shows significant response toward acetate ion with high selectivity, and meanwhile dramatic color change is observed from yellow to green in the presence of acetate ion (5 × 10−6 mol/L). Little UV–vis absorption spectrum change has occurred when receptor 2 was titrated with other different guest (F−, Cl−, Br−, I−, H2PO4− and OH−). In addition, the 1H NMR spectrum titration shows deprotonation of the receptor in the presence of acetate ion.