Fig. 3. Schematic illustration of (a) inter-cluster aurophilic interaction, (b) ligand exchange reaction, and (c) surface motif exchange reaction based on the Au–S interface of Au25(SR)18 (a), [Au25(SR)18]− (b), and [Au23(SR)16]− (c). (a) shows the formation of a 1D assembly by Au25(SR)18 based on the inter-cluster aurophilic interaction (colour code: golden, Au; red, S); reproduced with permission from ref. 106. Copyright 2014, American Chemical Society. (b) illustrates the preferential ligand exchange site on [Au25(S-C2H4Ph)18]− by HS-Ph-p-Br based on its crystal structure (top panel) and solvent-accessibility surface model (bottom panel), where blue arrows indicate the solvent-exposed Au and red arrows indicate the preferential ligand exchange site (colour code: orange, Au; yellow, S; grey, C; red, Br); reproduced with permission from ref. 107. Copyright 2014, American Chemical Society. (c) shows surface motif exchange induced size conversion from [Au23(SR)16]− to [Au25(SR)18]−; the glowing belts #1–#3 indicate SR–[Au(i)–SR]2 motifs formed in the size conversion process; reproduced with permission from ref. 61. Copyright 2018, the Authors, published by Springer Nature.
