[Cu₈₁(PhS)₄₆(^<i>t</i>BuNH₂)₁₀(H)₃₂]³⁺ Reveals the Coexistence of Large Planar Cores and Hemispherical Shells in High-Nuclearity Copper Nanoclusters

Abstract

Copper-based nanomaterials have attracted tremendous interest due to their unique properties in the fields of photoluminescence and catalysis. As a result, studies on the correlation between their molecular structure and their properties are of great importance. Copper nanoclusters are a new class of nanomaterials that can provide an atomic-level view of the crystal structure of copper nanoparticles. Herein, a high-nuclearity copper nanocluster with 81 copper atoms, formulated as [Cu₈₁(PhS)₄₆(^<i>t</i>BuNH₂)₁₀(H)₃₂]³⁺ (<b>Cu</b>_<b>81</b>), was successfully synthesized and fully studied by X-ray crystallography, X-ray photoelectron spectroscopy, hydrogen evolution experiments, electrospray ionization mass spectrometry, nuclear magnetic resonance spectroscopy, and density functional theory calculations. <b>Cu</b>_<b>81</b> exhibits extraordinary structural characteristics, including (i) three types of novel epitaxial surface-protecting motifs; (ii) an unusual planar Cu₁₇ core; (iii) a hemispherical shell, comprised of a curved surface layer and a planar surface layer; and (iv) two distinct, self-organized arrangements of protective ligands on the curved and planar surfaces. The present study sheds light on structurally unexplored copper nanomaterials and paves the way for the synthesis of high-nuclearity copper nanoclusters.