Triplet State of Triphenylamine

Abstract

Two transient species with absorption peaks at 5300 and 6100 Å have been observed in de-oxygenated solutions of triphenylamine by a flash photolysis technique^1,2. The major product at room temperature is said to have been the 6100 Å compound, and this was considered to be an “intermediate” from which N-phenyl carbazole was formed in the presence of oxygen. Low temperatures were said to favour the formation of the 5300 Å transient absorption and, because its decay rate at −150° C was identical with that of the phosphorescence, it was regarded as arising from triphenylamine in its lowest triplet state. These observations suggest that both “intermediate” and triplet species were always simultaneously present, whatever the temperature.