Radiation-induced reactions of nitroanthracene derivatives studied by gamma-radiolysis and pulse radiolysis

Gamma-radiolysis of 9-cyano-10-nitroanthracene (CN-NO₂-A) in ethanol at room temperature gave rise to the formation of 9-cyanoanthracene, 9-cyano-10-aminoanthracene and 10-cyano-9-anthrol. Addition of triethylamine (TEA) enhanced the formation of the aminocompound, and 10-cyano-9-anthrol decomposed completely into 9-cyano-10-anthryloxy anion. Similar reactions might also occur for 9-benzoyl-10-nitroanthracene based on the comparison of the absorption spectral change with that for CN-NO₂-A. In the presence of TEA, the transient spectra observed by pulse radiolyses at room temperature and gamma-radiolyses at 77 K were assigned to the radical anions of nitroanthracenes. Thus the formation of the aminocompounds was interpreted in terms of the electron transfer from the trapped electrons to nitroanthracenes followed by the protonation. In the absence of TEA, the new absorption bands were observed at 440-470 nm. We tentatively assigned these new absorption bands to the complexes of the radical anions of nitroanthracenes with the solvent radicals: the complexes may probably give rise to the formation of the final products other than the aminocompounds.