Intramolecular Transfer of Singlet Oxygen

The intramolecular transfer of energy (FRET) and electrons (Dexter) are of great interest for the scientific community and are well-understood. In contrast, the intramolecular transfer of singlet oxygen (¹O₂), a reactive and short-lived oxygen species, has until now been unknown. This process would be very interesting because ¹O₂ plays an important role in photodynamic therapy (PDT). Herein, we present the first successful intramolecular transfer of ¹O₂ from a donor to acceptor. Also, we found a dependence of conformation and temperature comparable with those of FRET. We provide several pieces of evidence for the intramolecular character of this transfer, including competition experiments. Our studies should be interesting not only from the theoretical and mechanistic point of view but also for the design of new ¹O₂ donors and applications in PDT.