Reactivity of a pyridinium-substituted dimethyldihydropyrene switch under aerobic conditions: self-sensitized photo-oxygenation and thermal release of singlet oxygen.

The behavior of a pyridinium-substituted dimethyldihydropyrene photo-switch under aerobic conditions was investigated. During irradiation with red light (λ ≥ 630 nm), this compound plays the role of oxygen sensitizer and is quantitatively converted into an endoperoxide derivative. The photo-produced endoperoxide then thermally releases singlet oxygen to regenerate the starting compound.