Raw data for "Excited perylene radical as strong photoreductant in water using red light"

Abstract

Excited organic radicals are emerging as powerful key species for driving highly demanding photocatalytic redox transformations. However, detailed characterization of these photoactive intermediates remains essential, and their operation in water has been largely unexplored. Herein, we report the design, investigation and utilization of a biphotonic consecutive photoinduced electron transfer (conPET) system operating in water that exploits the excited radical anion of perylene-3,4,9,10-tetracarboxylate (PTC·−) as a potent photoreductant. Sensitization of triplet PTC by an osmium complex, followed by reductive quenching with ascorbate, enables efficient formation of PTC·− with near-unity cage escape efficiency. Combined electrochemical, spectroscopic and computational analyses reveal an excited state oxidation potential of Eox(*PTC·−) ∼ −2.6 V vs SCE. Ultrafast two-color pump−pump−probe transient absorption spectroscopy identifies a short-lived excited doublet state (τ = 9.0 ps), thereby excluding the involvement of solvated electrons. The system enables biphotonic red light-driven reduction of quaternary ammonium compounds in water, including a harmful benzalkonium pollutant. Notably, the anionic nature of PTC·− in combination with its short excited state lifetime enabled selective reductions of cationic substrates via ion-pairing in the presence of anionic substrates. These in-depth spectroscopic and mechanistic investigations as well as initial applications establish PTC·− as organic radical super-reductant for aqueous photoredox catalysis.