Selective visible-light-driven oxygen reduction to hydrogen peroxide using BODIPY photosensitizers

Abstract

Selective visible-light-driven O₂ reduction to H₂O₂ was realized using BODIPY photosensitizers (PS) in the presence of ferrocene (Fc) as the reductant and acetic acid as the proton source. Mechanistic studies suggested that O₂ could be activated by ³PS* through an energy transfer pathway to give singlet oxygen (¹O₂) in the absence of Fc. However, with Fc, ³PS* was first reductively quenched to PS˙⁻, which was able to reduce O₂ to the superoxide radical form in a subsequent electron transfer step.