Contribution of the pyrylium structure to the electrochemical properties of nitroflavones

Abstract

The polarographic behavior of 3- and 4′-nitroflavones on a dropping mercury electrode in Britton-Robinson buffer solutions was investigated. It Is shown that, depending on its position, the nitro group displays properties that are typical only for aromatic nitro compounds or a combination of properties of aromatic and aliphatic α-unsaturated nitro compounds. The deciding factor is the realization of pyrylium and pyrone structures, depending on the pH of the medium. The kinetic parameters of the chemical transformation of the nitro form to the aci form of 3-nitroflavone in an alkaline medium are presented.