Programming Iron Nuclearity and Coordination for Hydride‐Mediated Nitroarene Reduction

ABSTRACT Multielectron catalytic reactions intrinsically rely on cooperative metal centers, yet constructing few‐atom cluster catalysts (FACCs) with controlled nuclearity, metal–metal connectivity, and electronic structure remains a fundamental challenge. Here, we show that atomically defined iron‐oxo clusters can serve as structure‐encoded precursors to generate supported Fe ensembles on N‐doped carbon (NC), enabling systematic construction of active sites spanning isolated atoms to size‐defined multinuclear clusters. During ligand removal and interfacial reconstruction, the molecular structural information is selectively inherited, giving rise to correlated evolution of Fe valence, Fe─Fe coordination and distance, and Fe─N anchoring interactions. Using hydrazine‐mediated nitroarene reduction as a model multielectron reaction, we uncover a pronounced nuclearity‐dependent transition in the reaction pathway, with optimal activity at intermediate nuclearity (Fe 6 ─NC), attributable to precursor‐dependent Fe─Fe cooperation and Fe─N interfacial coupling that stabilize surface hydride species. These findings provide a general basis for translating metal─oxo clusters into functional heterogeneous catalysts.