An atomically precise alloy AgCu cuboid nanocluster with a cubic core: gram scale synthesis, total structure, electronic structure, and catalytic performance†

Although atomically precise noble metal nanoclusters (NMNCs) are highly desirable to unravel the size and structure–activity relationships in catalysis, their synthesis in a controlled way at the atomic level is challenging. Herein, we report the structure and gram scale synthesis of a highly symmetric 2-phenylethanethiol (PETH) and triphenylphosphine (PPh₃)-protected AgCu alloy nanocluster (NC) [Ag₄Cu₂₈H₆(PET)₁₆Cl₈(PPh₃)₈][BF₄]₂ with a cuboid shape, denoted as Ag₄Cu₂₈. This was accomplished via a facile one-pot reduction method. The Ag₄Cu₂₈ NC consists of an Ag₄Cu₄ metal core, six hydrides, four Cu₄Cl₂ units, eight PET ligands, and four Cu₂(PET)₂(PPh₃)₂ motifs. High-resolution electrospray ionization mass spectrometry (HRESI MS) and density functional theory (DFT) calculations support this crystal structure. Moreover, Ag₄Cu₂₈ exhibits excellent catalytic activity (k = 7.86 min⁻¹) in the hydrogenation of hazardous nitroarenes. This intriguing NC delivers a unique opportunity to explore the gram scale synthesis of alloy nanoclusters and to expand the research on Cu and Ag-based NCs.