Photooxygenation of Diphenanthro[5,4,3-abcd : 5′,4′,3′-jklm]perylene

Abstract

Abstract The photooxygenation of diphenanthro[5,4,3-abcd : 5′,4′,3′-jklm]perylene (DPP) due to visible-light irradiation was investigated by measuring the absorption spectra and applying semi-empirical molecular orbital methods. It was shown theoretically that molecular oxygen attaches to the central benzene ring of DPP to give an endo-peroxide. The oxygen gradually detaches from the endo-peroxide at room temperature, reproducing DPP. The activation energies for both the reactions of oxygen attachment and detachment were determined based on the temperature dependences of the reaction rates in benzene; 10.0 ± 5.5 kJ mol−1 for the attachment reaction and 83.8 ± 2.5 kJ mol−1 for the detachment reaction.