In order to obtain more information on the hole-injecting properties of the excited state of anthanthrone, the photophysical properties of the excited singlet and triplet states of this molecule were investigated. The excited singlet state is situated at 20 480 cm-1 in benzene and its energy is slightly dependent on the solvent properties. On the assumption that all non-radiative decay of the singlet is due to intersystem crossing, the triplet energy is estimated to be 13 000 cm-1 in toluene using laser-induced opto-acoustic spectroscopy. Using laser flash photolysis it is observed that the triplet state can be quenched by tertiary aromatic amines. In benzonitrile the quenching leads to the formation of the radical anion of anthanthrone and the radical cation of the amine, whereas in benzene, for all quenchers investigated except N,N,N′,N′-tetramethylphenylenediamine, the semiquinone radical of anthanthrone is formed. When the oxidation potential of the amine is decreased the rate constant for the quenching of the triplet state of anthanthrone is increased in benzene and benzonitrile.
|Number of pages||13|
|Journal||Journal of Photochemistry and Photobiology, A: Chemistry|
|State||Published - 29 May 1992|