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

有人提出在细菌孢子中大量存在的二吡啶甲酸（DPA）在孢子光产物的形成中起内源性光敏剂的作用。拟议的机制涉及从DPA到胸腺嘧啶的三重态-三重态能量转移。但是，到目前为止，尚未进行任何光谱学研究来确定内源性化合物与核碱基之间的相互作用，这可能是由于其在水溶液中的可光化性。这里，DPA的三重激发态的属性是与由胸苷其双分子猝灭速率常数k一起报告_q约的 5.3×10 ⁹  M ^-1  s ^-1。为了进行更可靠的研究，还描述了一种稳定的DPA甲酯衍生物，该衍生物具有与母体化合物相同的光谱特性。最后，对DPA光产品进行了表征。对它们的三重态激发态性质的研究表明，有趣的是，其中之一能够使胸苷三重态激发态形成光敏。