Single‐Atom‐Modulated Reactive Oxygen Species Generation and Network Crosslinking in Porphyrin‐Based Metallacages for Selective Photocatalysis

Abstract Precise control over the photocatalytic selectivity by single atoms is ubiquitous in natural systems but remains a formidable challenge for artificial photocatalysts. Here, we present a series of porphyrin‐based metallacages with nearly identical architectures that differ only in the central metal atoms (Co, Ni, Cu, and Zn) of the porphyrin ligands. The distinct d ‐orbital electron distribution of these metal centers governs ligand‐to‐metal charge transfer, resulting in divergent reactive oxygen species (ROS) generation pathways. The Co–porphyrin cage promotes electron transfer to produce superoxide anion (O 2 •− ), whereas the Zn–porphyrin cage favors energy transfer to generate singlet oxygen ( 1 O 2 ); Ni‐ and Cu‐porphyrin cages exhibit dual behavior. These variations lead to distinct oxidation selectivity of α‐terpinene, yielding either p ‐cymene (via O 2 •− ) or ascaridole (via 1 O 2 ). Moreover, secondary coordination between the porphyrin metals and poly(4‐vinylpyridine) affords robust supramolecular networks for heterogeneous catalysis with enhanced stability and recyclability. This study establishes single‐atom modulation within metallacage frameworks as an effective strategy to control ROS generation and photocatalytic selectivity, paving the way toward the practical applications of metallacage‐based photocatalytic systems.