Participation of exciplexes in the photochemical reactions of trinuclear aromatic compounds with N,N′-dimethylaniline in solutions with various polarity

Characteristics of the photoreduction of trinuclear aromatic compounds (phenazine, acridine, and anthracene) by N,N-dimethylaniline (DMA) in media with various polarity (benzene and benzonitrile) were investigated. On the basis of the obtained relationships between the reciprocals of the quantum yields of photoreduction and the reciprocals of the DMA concentration and also on the basis of experiments with biacetyl it was established that the photoreduction is realized with the participation of the lowest excited S₁ and T₁ states. It was shown that the photochemical reduction of the trinuclear aromatic compounds takes place by a mechanism involving an exciplex.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 4, pp. 442–448, July–August, 1990.