Synthesis of a new azo Schiff base colorimetric chemosensor for detection of cyanide and acetate anions

In this paper, a novel azo Schiff base chemosensor was synthesized via condensation reaction of 4-Aminoantipyrine with 1-(3-Formyl-4-hydroxyphenylazo)-3-nitrobenzene. The imine sensor was studied via spectroscopic methods IR, 1HNMR and UV-Vis. The chromogenic behavior of colorimetric chemosensor toward various anions was investigated by UV–Vis spectroscopic. The chemosensor show abrupt changes towards CN− and OAC−anions in DMF/H2O solution in comparison with other anions. Upon the addition of CN− and OAC− ions to the receptor, the color of the L solution was changed from yellow to purple that was detectable with naked-eye and without any optical instrument. No color changes towards other anions were observed. The detection limits of the azo-azomethin sensor for OAC− and CN− anions were 2.6 ×10-5 and 1.4 ×10-6 mol L-1, respectively. Using the association constant value for sensor towards OAC− and CN− anions was calculated to be 4.2 ×103 and 3.07 ×104 M-1.