Horizontal expansion of biicosahedral M13-based nanoclusters: resolving decades-long questions

For metal nanoclusters with the cluster of clusters intramolecular evolution pattern, most efforts have been made towards the vertical superposition of icosahedral nanobuilding blocks (e.g., from mono-icosahedral Au-13 to bi-icosahedral Au-25 and tri-icosahedral Au-37), while the horizontal expansion of these rod-shaped multi-icosahedral aggregates was largely neglected. We herein report the horizontal expansion of the biicosahedral M-25 cluster framework, yielding an [Au19Ag12(S-Adm)(6)(DPPM)(6)Cl-7](2+) nanocluster that contains an Au13Ag12 kernel and six Au-1(DPPM)(1)(S-Adm)(1) peripheral wings. The structural determination of [Au19Ag12(S-Adm)(6)(DPPM)(6)Cl-7](2+) resolved a decades-long question towards rod-shaped multi-icosahedral aggregates: how to load bidentate phosphine and bulky thiol ligands onto the nanocluster framework? The structural comparison between [Au19Ag12(S-Adm)(6)(DPPM)(6)Cl-7](2+) and previously reported [Au13Ag12(PPh3)(10)Cl-8](2+) or [Au13Ag12(SR)(5)(PPh3)(10)Cl-2](2+) rationalized the unique packing of Au-1(DPPM)(1)(S-Adm)(1) motif structures on the surface of the former nanocluster. Overall, this work presents the horizontal expansion of rod-shaped multi-icosahedral nanoclusters, which provides new insights into the preparation of novel icosahedron-based aggregates with both vertically and horizontally growing extensions.

Automated summary

This study presents the horizontal expansion of rod-shaped multi-icosahedral nanoclusters and successfully synthesizes a nanocluster with an Au13Ag12 core and six Au-1(DPPM)(1)(S-Adm)(1) peripheral wings. The structural comparison reveals the unique arrangement of Au-1(DPPM)(1)(S-Adm)(1) motif structures on the surface of this nanocluster.