Perylene-Diimide-Based Supramolecular Radical Anion as a Platform for Highly Effective Photoreduction of Inert Sulfoxide to Sulfide.

Due to the limitations of common photoredox catalysts, unlocking their applications in photoreduction reactions remains an ongoing challenge. We herein present a supramolecular radical anion, PDI(CB[7])2, that formed by the assembly of perylene diimide derivative (PDI) and cucurbit[7]uril (CB[7]) via a host-guest interaction for an effective photoreduction reaction. Studies revealed that it could effectively accomplish a consecutive excitation process by two-photon excitation, enabling a potent photoreductant PDI(CB[7])2• - * that can even reduce the inert feedstocks, such as sulfoxides to sulfides. Mechanistic investigations indicate that, besides exceptional photophysical properties, supramolecular PDI(CB[7])2 also significantly enhances the lifetime and robustness of the in situ generated higher energy photoreductant PDI(CB[7])2• - * upon second quantum photon excitation, leading to the observed highly active photoreducing behavior.