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.