Gold-doped silver nanocluster [Au 3 Ag 38 (SCH 2 Ph) 24 X 5 ] 2- (X = Cl or Br).

Here we report the single-crystal structure, experimental and theoretical characterization of a 41-metal atom Au-Ag alloy nanocluster [Au3 Ag38 (SCH2 Ph)24 X5 ]2- (1, X = Cl or Br). The nanocluster 1 is co-protected by thiolate and halogen atoms and features an all-metallic face-fused biicosahedral Au2 @AuAg20 rod-like kernel enwrapped by the outermost Ag18 (SCH2 Ph)24 X3 shell. Two sites on the surface of the biicosahedral kernel are partially occupied by Au and Ag atoms. The outer Ag18 (SCH2 Ph)24 X3 shell is composed of two Ag6 S6 cycles at the two poles and one Ag6 S2 X3 arc at the equator with both 2- and 3-coordinated Ag atoms, which has not been observed in gold or silver nanoclusters ever before. Theoretical calculations elucidate its electronic structure as well as optical properties, thus producing informative correlations between its structure and properties. This nanocluster exhibits near-infrared (NIR) emission around 825 nm. This work (i) snapshots a rare crystal structure of an Au-doped silver alloyed nanocluster; (ii) gives a deep insight to understand how the capping ligand or anions affect the structure of the alloy nanocluster; and (iii) provides precise information about gold atom doping site that is very significant in the recognition of potential active catalytic sites of the alloy nanoparticles.