Spectroscopic characterization of dipicolinic acid and its photoproducts as thymine photosensitizers

Dipicolinic acid (DPA), present in large amount bacterial spores, has been proposed to act as an endogenous photosensitizer spore photoproduct formation. The mechanism involves a triplet-triplet energy transfer from DPA thymine. However, up now, no spectroscopic studies have performed determine the interaction between compound and nucleobase, probably due its photolability aqueous solutions. Here, triplet excited state properties of are reported together with bimolecular quenching rate constant by thymidine, kq ca. 5.3 × 109 M?1 s?1. To run more reliable studies, stable methyl ester derivative DPA, which exhibits same parent compound, is also described. Finally, photoproducts characterized. Studies their demonstrated that, interestingly, one them able photosensitize thymidine