Effect of H-bond formation on the electronic spectra of some azo compounds derived from 3-amino-1, 2, 4-Triazole

ABSTRACT

Despite the absorption spectra of azo compounds having been studied by several workers [1-12], little information has been reported about the spectral behaviour of the azo compounds derived from heterocyclic amines containing more than one heteronitrogen atom. The present investigation concerns a study on the electronic spectra of some azo compounds derived from 3-amino-1,2,4-triazole and various active methylene or active hydrogen compounds, in solvents of different polarities and basicities as well as in ones having hydrogen-bonding ability. This study was made with the intention of assigning each of the different observed absorption bands to their possible electronic transition and to investigate the effect of substituents on the tautomeric equilibrium of the azo compounds in solution. Moreover, the effect of aqueous buffer solutions of varying pH's on the spectral behaviour of the studied compounds was examined and used to determine the acidity constants of these compounds