Transient Intermediates in the Laser Flash Photolysis of Ketoprofen in Aqueous Solutions: Unusual Photochemistry for the Benzophenone Chromophore

摘要

The transient intermediates in the nanosecond laser flash photolysis of ketoprofen, an aryl propionic acid, show the formation of a carbanion in aqueous solutions at pH 7.1. This carbanion incorporates spectroscopic properties from both a ketyl radical anion and a benzylic radical. The ketoprofen carboxylat undergoes biphotonic photoionization, a process that contributes less than 10/100 to its photodecomposition and leads to a benzylic-type radical after decarboxylation with a rate constant ≥1 *10~7 s~-1.