High-nuclearity and thiol protected core-shell [Cu 75 (S-Adm) 32 ] 2+ : distorted octahedra fixed to Cu 15 core via strong cuprophilic interactions.

Atomically precise nanoclusters have a critical role in understanding the structure-property relationships at the atomic level. Copper nanoclusters have attracted considerable attention, but the synthesis is limited because of susceptibility to oxidation. Herein, we developed a reduction speed controlling method to synthesize [Cu(S-Adm)] (HS-Adm: 1-Adamantanethiol) nanocluster and reveal the key steps in the nucleation process. Cu was first observed and characterized with the following features: (i) composed of a face-centered cubic Cu kernel and a Cu caged shell including 12 distorted octahedra. (ii) The observation of the shortest Cu-Cu bond (2.166(7) Å) in the Cu nanoclusters, which could result from the distortion of the octahedron. (iii) The sole μ-S mode of S, which plays two roles as a vertex and bridge atom to connect Cu atoms. This work presents a unique nanoball Cu nanocluster with strong cuprophilic interaction and provides a novel method to expand the family of Cu nanoclusters as well.