Role of the 3(n—π*) State in the Photoreduction of Acridine

Abstract
Photosensitization of acridine reduction by benzophenone is shown to occur via the ketyl radical of benzophenone rather than by an energy‐transfer mechanism. The principal evidence for participation of an upper triplet n—π* state of acridine in the photoreduction reaction is therefore discounted and the reaction probably occurs via the lowest excited singlet level.