Reduction of isoviolanthrone by reaction with photogenerated radicals

Photochemical & Photobiological Sciences Pub Date: 2011-06-28 DOI: 10.1039/C1PP05086A

Abstract

The properties of isoviolanthrone (V1) and its corresponding dihydro form (V1–H2) in argon-saturated 1-phenylethanol in the presence of acetophenone were examined by photophysical and photochemical methods. Upon photolysis of the sensitizer, a radical-induced reduction of V1 to V1–H2 occurs. The quantum yield of this reduction is close to unity. The fluorescence of V1 has a quantum yield of 0.08, for V1–H2Φf is strongly enhanced and the emission maximum is blue-shifted. The ketyl radical, the semiquinone radical and V1–H2 were observed in this sequence by flash photolysis. V1–H2 is unstable and undergoes oxidation to V1 on admission of oxygen.

Graphical abstract: Reduction of isoviolanthrone by reaction with photogenerated radicals
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