Time-resolved resonance Raman and density functional theory investigation of the photoreactions of benzophenone in aqueous solution.

A time-resolved resonance Raman study of the photoreactions of benzophenone (BP) in neutral, alkaline, and acidic aqueous solutions is reported. Under neutral and alkaline conditions, a hydrogen abstraction reaction is observed to form the corresponding diphenyl ketyl (DPK) radical with different reaction rates while under acidic condition the protonation of triplet benzophenone occurs simultaneously, which is followed by a faster hydration reaction to produce the corresponding photohydration short-lived intermediates that were observed during experiments and that were tentatively assigned to the m-(3)BP x H(2)O and the o-(1)BP x H(2)O species. The dynamics, structures, and properties of these species are briefly discussed.