Structural and Electronic Features of an Au 10 Ag 14 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.