Bidentate Phosphine-Assisted Synthesis of an All-Alkynyl-Protected Ag74 Nanocluster

Determining the total structure of metal nanopartides is vital to understand their properties. In this work, the first all-alkynyl-protected Ag nanocluster, Ag-74(C CPh)(44), was synthesized and structurally characterized. by single crystal diffraction. Ag atoms are arranged in a Ag-4@Ag-22@Ag-48 three shell structure and all 44 phenylethynyl ligands coordinated with Ag in a mu(3) mode. In spite of being absent in nanocluster, P-31 NMR study reveals that bidentate phosphine first reacts with Ag(I) to form a dinuclear complex, from which Ag atoms are then released to phenylethynyl ligands. This phosphine mediated strategy may find general application in synthesis of alkynyl-protected Ag nanoclusters.