Selective ·O²- and ¹O₂-promoted photocatalytic organic transformations by regulating the exciton dynamics through dimensionality control of the PDI-based polymers

Governing the energy transfer (EnT) or electron transfer (ET) excitation pathway to dictate reactive oxygen species (ROS) is crucial for selectivity, yet challenging to achieve with simple molecular designs in highly active systems. Herein, by utilizing the oxygen dependency of ·O₂⁻ and ¹O₂, we present a simple but effective approach to regulate exciton behavior via the construction of perylene diimide (PDI)-based polymers. It is established that the product of ROS is governed by the molecular structure through its control over the solid-state packing and host–guest interactions. The planar geometry of PDI-pCZ-CHCl₃ facilitates the dense molecular stacking, creating an electron-rich environment that promotes the direct reduction of substrates via type I pathway (dominated by electron transfer) to form ·O₂⁻. Conversely, the hypercrosslinked non-planar cationic PDI-pCZ-DCE culminates in a high-surface-area architecture with low O₂ adsorption free energy, and preferentially concentrates and activates the molecular oxygen through type II pathway (dominated by energy transfer) to generate ¹O₂. Both the PDI-based polymers exhibit good photothermal effect for overcoming the reaction energy barriers, thereby improving the reaction kinetics. The verification of the selective generation of ¹O₂ and ·O₂⁻ of these photocatalysts is implemented on the model reactions, showing that the photosynthesis of 1,2,4-thiadiazoles mediated by ¹O₂ is up to 92% isolated yield, while the phenols production from phenylboronic acids dominated by ·O₂⁻ is up to 88% yield. This work provides an important fresh platform for advancing the selective O₂ activation and the respective ET/EnT-dominated photocatalytic scenario.