Crystallographic Visualization of the Missing Structural Evolution of Copper Nanoclusters

Copper nanoclusters have recently garnered immense interest across chemistry and materials science, yet precise control over their growth processes is hindered by a limited fundamental understanding of structural evolution. Here, we unlock atomic-level insights into their structural evolution by determining the structures of six distinct clusters─Cu₁₂, Cu₂₃-a, Cu₂₃-b, Cu₂₅-a, Cu₂₅-b, and Cu₆₁─isolated from a single synthetic system employing a disulfide-mediated protection strategy. By precisely tuning the reaction temperature and time, we strictly control the growth kinetics within this system. Single-crystal X-ray diffraction uncovers that hexameric Cu₃S₃ and octameric Cu₄S₄ rings act as versatile modular motifs, which encapsulate well-defined metal kernels to direct the structural evolution of all-thiolate-protected copper nanoclusters. Notably, structural isomerization is observed within this cluster series. By presenting the first experimental evidence from a homologous series of size-incremental copper-thiolate nanoclusters, this work provides atomic-level insights into how fundamental building motifs and surface coordination chemistry cooperatively direct the targeted synthesis of functional copper nanoclusters.