Molecular Stacking Dependent Molecular Oxygen Activation in Supramolecular Polymeric Photocatalysts

Here, we showed that supramolecular assemblies based on perylene diimides (PDIs) are able to activate molecular oxygen through both the electron transfer and energy transfer pathways, which consequently leads to the formation of superoxide radicals (·O₂^-) and singlet oxygen species (¹O₂), respectively. These reactive oxygen species (ROS) can effectively lead to oxidative coupling of benzylamine and oxidation of 2-chloroethyl sulfide (CEES). We have designed and synthesized PDIs with similar molecular structures yet differing by the molecular stacking modes. We found that the photooxidation activities of the PDI supramolecular assemblies are inversely associated with the photoluminescence wavelength difference between the assemblies and the monomers (Δλ) quantitatively, and a smaller Δλ results in a higher catalytic efficiency accordingly. Overall, this work contributes to the design and fabrication of high performance photocatalysts based on metal-free organic materials.