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

Abstract

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.