Enriching Structural Diversity of Alkynyl-Protected Gold Nanoclusters with Chlorides

This work describes the synthesis and isolation of alkynyl/chloride-protected gold nanoclusters. Silica gel column chromatography works effectively in isolating gold nanoclusters from the as-synthesized cluster mixture to give three clusters Na[Au 25 L 18 ] ( Au 25 ), [HNEt 3 ] 3 [Au 67 L 32 Cl 4 ] ( Au 67 ), [HNEt 3 ] 4 [Au 106 L 40 Cl 12 ] ( Au 106 ), where L = 3,5-bis(trifluoromethyl)-phenylacetylide. Au 67 and Au 106 are new clusters and their total structures have been determined by X-ray single crystal diffraction. Au 67 contains a distorted Au 18 Marks decahedron shelled by an irregular Au 32 and further protected with two V-shaped Au 2 L 3 , 13 linear AuL 2 staples and four chlorides. Au 67 is the first structurally determined 34e superatomic gold nanocluster. Au 106 is composed of 106 Au atoms co-protected by alkynyls and chlorides. It has a Au 79 kernel, which is the same as that in Au 102 ( p -MBA) 44 . The surface structure of Au 106 includes 20 linear Au-alkynyl staples, five Cl-Au-Cl and two Cl-Au motifs. These three gold nanoclusters show size-dependent electrochemical properties. The combination of chloride and alkynyl pave a new path toward enriching structural diversity of gold nanoclusters.