Intramolecular Electron Transfer between Tyrosine and Tryptophan Photosensitized by a Chiral π,π* Aromatic Ketone

The photochemical reaction of Trp and Tyr and related peptides with Suprofen (SUP) as sensitizer in H 2 O/CH 3 CN (28:1 v / v ) solutions has been studied by time‐resolved spectroscopy. The results show that SUP induces oxidation of both Trp and Tyr, as well as intramolecular‐ET reactions in the related peptides. The influence of photosensitizer configuration on the involved processes has been studied by using the enantiomerically pure compounds. A significant chiral recognition is observed in which the concentration of the radicals formed after triplet quenching depends on the configuration of the chiral center; the quenching process is higher when using the ( R )‐SUP enantiomer.