Excited state deprotonation reactions of aromatic amines: a diffusion-controlled process

Abstract

The excited state proton transfer reactions of carbazole (CAZL), indole (IND) and diphenylamine (DPA) were studied using a picosecond time-resolved technique. The forward rate constant for deprotonation shows a slight temperature dependence. The activation energy for the process was determined by taking various bases in both aqueous and non-aqueous media. It is of the order of the diffusional barrier in the solution phase. Hence it is concluded that the process is diffusion controlled. The values of the diffusion-controlled rate constants are discussed.