Photogeneration of 2-deoxyribonolactone in benzophenone-purine dyads. Formation of ketyl-C1' biradicals.

Photolysis of the title dyads under aerobic conditions leads to a 2-deoxyribonolactone derivative. Laser flash photolysis reveals that the process occurs from the short-lived benzophenone-like triplet excited state. A mechanism involving intramolecular electron transfer with the purine bases (adenine, guanine, or 8-oxoadenine) as donors is proposed.