Sequential Vertex-Specific Modulation of Enantiopure Metal Nanoclusters

Controlled modulation of the specific crystal surfaces is vital in nanotechnology but remains challenging to implement. Here, we achieve sequential vertex modulation in atomically precise homochiral silver nanoclusters using a scalable crystallization synthesis. By tuning the reductant conditions, we generate mixed-phase cocrystallized R/S-Ag19·Ag20 comprising enantiopure R/S-Ag19 and R/S-Ag20, featuring the first icosahedral Ag13 core with 6 electrons. Using kinetic and thermodynamic control, we sequentially add Ag atoms to the cubic facets, progressing from the Ag6 shell in R/S-Ag19 (two missing vertices) to the Ag7 shell in R/S-Ag20 (one missing vertex), and ultimately to the closed Ag8 shell in R/S-Ag21, and luminescence is induced. This geometric evolution is reminiscent of the arachno → nido → closo transformations in borane clusters, where vertex recovery leads to increasingly close polyhedral frameworks. Shell closure results in 2e filling, symmetry adaptation and chirality mutation. Additionally, R/S-Ag21 enables quantitative chiral sensing of amino acids. This work advances nanosynthesis by providing a framework for controlling surface modulation and fine-tuning the nanocluster properties and can be used to facilitate the development of improved functional (chiral) nanomaterials.