Structural and Electronic Features of an Au₁₀Ag₁₄ Nanocluster Formed by Icosahedral Core Fusion

The structural chemistry of metal nanoclusters assembled through cluster-cluster interactions remains a focus of current research. Here we report the synthesis, structural characterization, and electronic properties of two ligand-protected nanoclusters, Au₅Ag₁₂(SR)₉(dppf)₄ (denoted as Au₅Ag₁₂, SR = SPhF₄-p-CF₃, dppf = Ph₂P-Fe(Cp)₂-PPh₂) and Au₁₀Ag₁₄(SR')₈(dppm)₆Cl₂ (denoted as Au₁₀Ag₁₄, SR' = SPh-p-CF₃, dppm = Ph₂P-CH₂-PPh₂). Single-crystal X-ray diffraction shows that the Au₁₀Ag₁₄ nanocluster contains a reconstructed metal core formed via fusion of smaller icosahedral subunits. Electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) supports the molecular compositions of both clusters. Density functional theory (DFT) calculation confirms that Au₅Ag₁₂ adopts an 8-electron Ne-type superatomic configuration, while Au₁₀Ag₁₄ displays a 14-electron F₂-type supermolecular character. These results provide structural and electronic insight into rare core-fusion pathways in metal nanoclusters and contribute to a deeper understanding of synthesis growth.