A novel, simple, colorimetric receptor based on 2 ',4 '-dinitrophenylhydrazone for acetate ion in organic medium

Abstract

A novel 1,3-di(2',4'-dinitrophenylhydrazone)-5-nitrobenzene receptor has been synthesized by simple steps with good yields. The anion recognition properties were studied by ultraviolet-visible (UV-Vis) spectroscopy. The results showed that the receptor had a higher affinity to F-, CH3COO- and H2PO4 (-), but no evident binding with Cl-, Br-, and I-. Upon addition of the three former anions to the receptors in dimethyl sulphoxide (DMSO) at 298.2 +/- A 0.1 K, the solution exhibited an obvious color change from yellow to mauve that could be observed by the naked eye, thus the receptor could act as a fluoride ion sensor even in the presence of other halide ions. The UV-Vis data indicates that a 1:1 stoichiometry complex formed through hydrogen-bonding interactions between receptor and anions. The hydrogen bond between phenylhydrazone -NH and acetate or fluoride anion was determined on the basis of H-1 nuclear magnetic resonance (NMR) experiments.