The pH- and wavelength-dependent pathways for the photodecarboxylation of ketoprofen (KP) were mapped by CASSCF/CASPT2 computations. The decarboxylation of the basic form (KP(-)) was found to start from a long-distance charge transfer (CT) excited state when populated by photoexcitation at 330 nm. A short-distance CT excited state populated with photoexcitation at λ < 260 nm appears to be responsible for the decarboxylation of the acidic form (KP). The H(2)O molecules function as a bridge to assist proton transfer in the reactions examined here.
© 2011 American Chemical Society