Electrochemical proof of the single bond character of the N-N bonds in some 1,2,4-triazines

Abstract

Whereas in molecules containing grouping X=C-C=Y (X,Y = C, O, N, S) delocalization of electrons takes place. In compounds containing the grouping C=N-N=C the central N-N bond has a single bond character and conjugation does not play a role. The single bond character of the N(1)-N(2) bond in 1 ,2,4- triazin-5-ones has been confirmed based on identity of reduction potential of the 1 ,6-azomethine bond in the parent compound and of the 1,6-C=N bond in the corresponding 2,3- dihydroderivative. Lack of delocalization has also been proved for acyclic azines. Comparison of half-wave or peak potentials is a simple and efficient way to prove or disprove the role of the delocalization of electrons over the studied molecule.