Gram-Scale Synthesis of N2-Type Ag32 Superatomic Molecule and Its Catalytic Reduction of 4-Nitrophenol.

Cluster assembly serves as an effective approach for tuning cluster properties, ‌where the electronic states arising from fused units play a crucial role in property design, thus attracting attention. In this work, we synthesized a Ag32 cluster via a one-pot method, featuring a Ag22 core formed by fusion of two icosahedral Ag13 units, with the core protected by a crown-like motif and two Ag1S2 staples. Further analysis reveals that the Ag22 core harbors 10 free electrons, which are partitioned equally as 5 electrons per icosahedral Ag13 subunit-constituting the first observation of the minimum electron count (5e) for such a moiety. This 5e/5e partitioning mirrors N2, where each N contributes five valence electrons. DFT calculations confirm this analogy, showing that Ag32 adopts an electronic structure closely akin to N2, establishing a superatomic molecular configuration. Remarkably, like N2, this cluster also exhibits robust stability under multiple conditions, including acid, alkali, and reducing conditions. Based on its stability, gram-scale synthesis of the Ag32 cluster was readily accomplished. Finally, we investigated its catalytic performance using the 4-nitrophenol reduction as a model reaction, revealing that the Ag32 cluster exhibited the highest catalytic activity among comparable clusters (5 min vs. >60 min).