Photochemistry of cerium(IV) ammonium nitrate (CAN) in acetonitrile

[Display omitted] •Mechanism of cerium(IV) ammonium nitrate (CAN) photolysis in CH3CN is presented.•Inner-sphere electron transfer was found to be the primary photochemical process.•High quantum yield of NO3 formation (0.6 and 0.4 upon 308 and 355 nm excitation).•Rate constants of reactions responsible for NO3 decay are measured.•A part of excited CAN molecules form the radical complex [(NH4)2CeIII(NO3)5…NO3]. Cerium ammonium nitrate (NH4)2CeIV(NO3)6 (CAN) is widely used as a photolytic source of NO3 radicals in acetonitrile. In spite of that, the mechanistic aspects of CAN photochemistry were poorly discussed in the literature. In this work CAN photochemistry in CH3CN was studied using the combination of stationary methods and laser flash photolysis. In accordance with the literature, the inner-sphere electron transfer was found to be the primary photochemical process. The (NH4)2CeIII(NO3)5(CH3CN) complex was found to be the only reaction product formed with the rather high quantum yield (0.6 and 0.4 upon 308 and 355 nm excitation correspondingly). The NO3 radicals decay is mainly caused by the second-order reactions; their rate constants are determined. In addition to the direct release of the NO3 radicals, a part of the light-excited CAN molecules were found to form the radical complex [(NH4)2CeIII(NO3)5…NO3], which lifetime is ca. 2 μs.