Overcoming the Oxygen Dilemma in Photoredox Catalysis: Near-Infrared (NIR) Light-Triggered Peroxynitrite Generation for Antibacterial Applications.

The peroxynitrite anion (ONOO ) is closely associated with many diseases and the creation of ONOO donors is an essential means of understanding its pathophysiological functions. However, it is challenging to develop ONOO donors due to the difficulties in simultaneously producing highly reactive and short-lived nitric oxide (NO) and superoxide anion (O ⋅ ). Here, we report a novel strategy for constructing ONOO donors by combining near-infrared (NIR)-mediated type I photosensitization and photoredox catalysis. The key design using a Nile blue analogue that can serve as both a type I photosensitizer and a metal-free photocatalyst. Intriguingly, the formation of O ⋅ via type I photosensitization avoids oxygen interference and instead activates nitrobenzofurazan-based NO donors via oxygen-tolerant NIR photoredox catalysis. The simultaneous release of O ⋅ and NO leads to ONOO release, showing both antibacterial and antibiofilm activities.