Structural aspects of the mechanism of photochemical radical pair formation in crystalline fluorene containing acridine

Abstract

In previous work [l] experiments have been reported to demonstrate that, in crystalline fluorene (CH the a&dine triplet state is concluded to be an unlikely precursor of this radical pair. We investigated the structural aspects of the acridine molecules as guests in the fluorene crystal, with acridine simulated to be in either the ground state or excited states, by the method of atom-atom potential energy functions. The results show that in either case only a relatively small distance prevails between the nitrogen atom of a guest molecule and a hydrogen atom of a methylene group in adjacent fluorene host molecules, thus facilitating the hydrogen atom transfer process. The structure of the radical pair is also being investigated.