Enriching Structural Diversity of Alkynyl-Protected Gold Nanoclusters with Chlorides

The synthesis and isolation of alkynyl/chloride-protected gold nanoclusters is described. Silica gel column chromatography is effective in isolating gold nanoclusters from the as-synthesized cluster mixture to give the clusters Na[Au25L18] (Au-25), [HNEt3](3)[Au67L32Cl4] (Au-67), [HNEt3](4)[Au106L40Cl12] (Au-106), L=3,5-bis(trifluoromethyl)-phenylacetylide. Au-67 and Au-106 are new clusters; the structures were 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 Au2L3, 13 linear AuL2 staples and 4 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, like in Au-102(p-MBA)(44). The surface structure of Au-106 includes 20 linear Au-alkynyl staples, 5 Cl-Au-Cl and 2 Cl-Au motifs. These three gold nanoclusters show size-dependent electrochemical properties.

Automated summary

The article describes the synthesis and isolation of alkynyl/chloride-protected gold nanoclusters, and presents the structures of three different clusters, including the new clusters Au-67 and Au-106 with complex surface structures and unique electrochemical properties.