Supramolecular photochemistry of 2-(3-benzoylphenyl)propionic acid (Ketoprofen). A study in the β-cyclodextrin cavity

Abstract

The photochemistry of 2-(3-benzoylphenyl)propionic acid (Ketoprofen) has been studied in the β-cyclodextrin cavity by stationary and time-resolved (picosecond and nanosecond) spectroscopic techniques. Conformational calculations of the inclusion complex were performed. Induced circular dichroism was measured and theoretically interpreted. Photodecarboxylation was found to occur with lower quantum yield than in aqueous medium. An additional photoreaction was evidenced. A mechanism in which the lowest triplet state of the Ketoprofen–β-cyclodextrin inclusion complex undergoes both intramolecular electron transfer and hydrogen abstraction is proposed. Adducts of reduced ketoprofen with β-cyclodextrin are the likely photoproducts of the additional reaction channel.