Formation of hydroxyl radicals by irradiated 1-nitronaphthalene (1NN) : oxidation of hydroxyl ions and water by the 1NN triplet state
Sur, B.; Rolle, M.; Minero, C.; Maurino, V.; Vione, D.; Brigante, M.; Mailhot, G.
Photochemical and Photobiological Sciences Official Journal of the European Photochemistry Association and the European Society for Photobiology 10(11): 1817-1824
ISSN/ISBN: 1474-9092 PMID: 21922113 DOI: 10.1039/c1pp05216k
The excited triplet state of 1-nitronaphthalene ((3)1NN*) reacts with OH(-) with a second-order reaction rate constant of (1.66 ± 0.08)×10(7) M(-1) s(-1) (μ±σ). The reaction yields the ˙OH radical and the radical anion 1NN(-)˙. In aerated solution, the radical 1NN(-)˙ would react with O(2) to finally produce H(2)O(2) upon hydroperoxide/superoxide disproportionation. The photolysis of H(2)O(2) is another potential source of ˙OH, but such a pathway would be a minor one in circumneutral (pH 6.5) or in basic solution ([OH(-)] = 0.3-0.5 M). The oxidation of H(2)O by (3)1NN*, with rate constant 3.8 ± 0.3 M(-1) s(-1), could be the main ˙OH source at pH 6.5.