Visualization of Total Synthesis from Au to Au Nanoclusters.

The emergence of geometrically related Au and Au nanoclusters (NCs), both possessing a valence electron count of 8e, has substantiated the feasibility of chemically preparing reduced metal nanoclusters. Nevertheless, a significant challenge remains: the dynamic transformation pathways governing their structural evolution have remained elusive, severely impeding precise atomic-level control in NCs synthesis. Herein, we present a large conjugated quinoline thiol ligand with protonatable sites, which enables the systematic construction of seven structurally related Au NCs. For the first time, this approach achieves continuous visualization of the total synthesis and core-shell evolution process from Au to Au NCs. Notably, we successfully synthesized and characterized a metastable corner-missing gold icosahedron NC (Au@Au) as a key intermediate through crystallographic methods. These advancements provide unprecedented insights into the nucleation mechanism of classical icosahedral Au NCs, particularly by elucidating how ligand-shell modifications precisely influence geometric rearrangement, electronic structure, and functional performance. The stepwise reaction pathways demonstrated in the Au NC series illustrate that metal NC synthesis can achieve organic chemistry-level precision when guided by strategic ligand engineering.