INFLUENCE OF THE ACIDITY LEVEL CHANGE IN APROTIC MEDIA ON THE VOLTAMMETRIC BEHAVIOR OF NITROGABACINAMAMIDES

摘要

This work presents a comparative voltammetric study of o-,m-and p-nitrogabacinamamides, NGs, in acetonitrile. These compounds, a HDR-NO_2 nitro compounds type, display three reduction waves, two of them are waves similar to those appearing in the reduction of the nitro compounds lacking a proton donor group and one new wave at less negative potentials, associated with the nitro-to-hydroxylamine reduction through a self-protonation reaction. The experiments were carried out in the presence of different chemical species giving an acidity level control by homogeneous buffer systems. The comparison of the different voltammetric behavior in the presence of the diverse acidic and basic additives allowed constructing an acidity level scale where the various acid base couples of the intermediaries of the NGs electroreduction were placed. This kind of scales allows choosing the chemical conditions necessaries to drive the pathway of the electrochemical transformation of nitro compounds.