A specific resistance of aminoazo dyes to the oxidative degradation

The primary products of one-electron oxidation of the azo dyes, 4-(N,N-diethylamino)azobenzene and 4-(N,N-dimethylamino)-4′-(N,N-diethylamino)azobenzene, have been spectroscopically characterized in cryogenic matrices. The reactivity of the radical cations has been investigated by means of pulse radiolysis in solution at room temperature and in cryogenic glasses. The primary transient products formed upon one-electron oxidation of the dyes are radical cations and alkylamino radicals. The latter products are efficiently scavenged by the dyes resulting in adduct formation. The adducts slowly decay and regenerate the parent dye. Hence the degradation of the dye initiated by one-electron oxidation becomes completely inefficient.