Photoreactive State of Acridine in Solution

The technique of energy transfer has been used in an attempt to establish the photoreactive state of acridine in solution. It is shown that the lowest-lying triplet of acridine, the ππ* triplet, is not the reactive species and that the reaction originates, at least in part, through the nπ* triplet. In the course of this work, the transfer of triplet-state energy from biacetyl to acridine, phenazine, anthracene, 1,2-benzanthracene, pyrene, 1,2-benzpyrene and 3,4-benzpyrene has been studied by an intensity method.