Laser flash photolysis studies on the interaction between triplet benzophenone and naphtholate anions. Electron transfer or triplet energy transfer?

By means of nanosecond laser flash photolysis it has been found that the interaction between triplet benzophenone (3BP∗) and naphtholate anions (NpO−) is not triplet energy transfer but electron transfer to yield the benzophenone anion (BP−·) and naphthoxy (NpO·) radicals in acetonitrile-H2O (4:1 v/v) at 295 K. From the kinetic parameters for quenching of 3BP∗ by NpO− and quantum yields for the formation of BP−· and NpO·, it was found that the efficiency for electron transfer between 3BP∗ and NpO− is unity due to the triplet spin-multiplicity of radical pairs.