Pulse radiolysis and flash photolysis studies of arylalkylamines in aqueous solutions - primary photoprocesses

Abstract

The photophysical processes leading to photoionization and photodissociation in the arylalkylamines benzylamine and benzhydrylamine were examined as a function of pH in aqueous solution using a KrF excimer laser. The main photolytic reaction observed for the amines is photoionization. The hydrated electron subsequently reacts with the amine leading to deamination when the amino group is in the protonated form, whereas, at pH≈11.0, e_aq^- adds to the benzene ring. Photodissociation processes occurring via C-H and C-C bond rupture are also observed and various transient intermediates can be identified by generation in appropriate pulse radiolysis experiments under suitable conditions. The two-step photoionization occurs via the triplet excited state as indicated by the heavy atom effect. In contrast, photodissociation occurs via a monophotonic process.