Symmetry Breaking of Atomically Precise Fullerene-like Metal Nanoclusters

• Published in: Journal of the American Chemical Society Vol. 143; no. 32; pp. 12439 - 12444
• Main Authors: Huang, Jia-Hong, Si, Yubing, Dong, Xi-Yan, Wang, Zhao-Yang, Liu, Li-Ying, Zang, Shuang-Quan, Mak, Thomas C. W
• Format: Journal Article
• Language: English
• Published: American Chemical Society 18.08.2021
• Subjects: acetonitrile; ligands; optical isomerism
• ISSN: 0002-7863; 1520-5126; 1520-5126
• DOI: 10.1021/jacs.1c05568

Here we report a neutral fullerene-like core–shell homosilver Ag13@Ag20 nanocluster that is fully protected by an achiral bidentate thiolate ligand (9,12-dimercapto-1,2-closo-carborane, C2B10H10S2H2), which crystallizes in centrosymmetric space group R3̅. Continuous Cu doping in the dodecahedral shell first induced symmetry breaking to generate chiral Ag13@Ag20‑n Cu n (6 ≥ n ≥ 2) containing two acetonitrile ligands in space group P212121, and then produced symmetric all-thiolated Ag13@Ag20‑n Cu n (20 ≥ n ≥ 13) in the higher space group Im3̅. The selectively copper-doped Ag13@Ag20‑n Cu n (6 ≥ n ≥ 2) cluster has its structure reorganized to a lower symmetry that shows chiroptical activity. Moreover, structural distortion of Ag13@Ag20‑n Cu n (6 ≥ n ≥ 2) further expanded in chiral R-/S-propylene oxide, which induced a more prominent core-based CD response. This work revealed a novel mechanism of chirality generation at the atomic level through asymmetric shell-doping of metal nanoclusters, which provides new insight into the origin of chirality in inorganic nanostructures.