Photochemical Reactions of Acridan Studied by CIDNP

Abstract The method of chemically induced dynamic nuclear polarization (CIDNP) is applied to investigate the photochemical reactions of acridan and some substituted acridans in alcoholic solutions at room temperature. It is shown that the CIDNP effect is due to the radical pair N‐radical ‐ H. which is formed from a triplet precursor. In the presence of CCl4 or CHCl3, the pair N‐radical, ·CCl3 (or ·CHCl2) is formed by direct reaction from the singlet state.