Structurally simple azo based chromogenic R1 for the selective sensing of cyanide ion in aqueous medium

Abstract

Structurally simple azo linked Schiff base R1 was synthesized and characterized using IR, 1H NMR and mass spectroscopic techniques. The selective sensing of cyanide anion over other anions such as fluoride, chloride, bromine, iodide, acetate, nitrate, hydrogen sulphate and dihydrogenphosphate was revealed by naked-eye color change and UV–vis spectra. Addition of CN− ions to the R1 showed a dramatic change in color from pale yellow to intense yellow along with the formation of a new band at 415nm in the absorption spectrum even in 100% aqueous medium. The interaction between R1 and cyanide was also investigated using 1H NMR titration study. The R1 showed limit of detection (LOD) up to micromolar level at 2.72×10−6M. Job's plot reveals the existing binding mode of R1 and CN− ion in molar ratio of 1:1 (R1:CN−).