Ligand Engineering-Driven Visualization of Asymmetric Exchange: Unraveling the Structural Evolution of Ag₃₁ to Ag₂₅

Precisely structured nanoclusters provide ideal platforms for elucidating structural evolution and structure–activity relationships. However, mechanistic understanding of dynamic core–shell rearrangements has long been impeded by the elusive nature of intermediates during transformation processes. Here, we show that ligand engineering-driven asymmetric thiolate exchange enables atomic-level visualization of structural evolution, thereby overcoming the long-standing challenge of intermediate capture. By systematically tracking metastable states using electrospray ionization mass spectrometry (ESI-MS) and crystallographic analysis, we reveal the stepwise conversion from Ag31(Dppm)3(SAdm)17(CH3CN)3 to Ag25(Dppm)3(SAdm)8(SCy)9 nanoclusters, uncovering how asymmetric ligand distribution triggers core restructuring (Ag16 → Ag13@Ag3 → Ag13) and subsequent shell reorganization. This strategy bridges the gap between structural dynamics and functional properties, offering a robust paradigm for dissecting complex nanocluster transformations.