Deciphering icosahedra structural evolution with atomically precise silver nanoclusters

Determining the atomic structure of nanoparticles (NPs) is critical for understanding their structural evolution and properties. However, controlling the growth of multiply-twinned metal NPs remains challenging because of numerous competing pathways. In this work, we report the synthesis of two giant silver icosahedral nanoclusters, [Ag₂₁₃(C≡CR1)₉₆]^5- and [Ag₄₂₉Cl₂₄(C≡CR2)₁₅₀]^5- (Ag₂₁₃ and Ag₄₂₉, R1 =3,4,5-F₃C₆H₂ and R2 = 4-CF₃C₆H₄), achieved through ligand engineering and kinetic control. Single-crystal x-ray diffraction reveals that Ag₂₁₃ and Ag₄₂₉ have multilayered icosahedral Ag₁₄₁ |(Ag₁₃@Ag₄₂@Ag₈₆) and Ag₂₉₇ (Ag₁₃@Ag₄₂@Ag₉₂@Ag₁₅₀) cores, respectively. Notably, Ag₄₂₉ with 260 valence electrons is the largest Ag⁰-containing nanocluster reported to date. These two giant silver nanoclusters are metallic in nature, as confirmed by their plasmonic absorption and pump-power-dependent excited-state dynamics. Their atomically precise structures support the layer-by-layer evolution from nuclei to seeds of silver icosahedra.