Chiral Superatomic Nanoclusters Ag47 Induced by the Ligation of Amino Acids.

Silver nanoclusters containing Ag0 atoms protected by amino acids were synthesized and characterized. Chiral superatomic silver nanoclusters [Ag47L12(C≡CtBu)16]BF4 (L=l‐/d‐valine or l‐/d‐isoleucine) have been prepared by reducing AgC≡CtBu and amino acids (AAs) with NaBH4. Single crystal X‐ray diffraction revealed that these clusters have T symmetry, and the Ag47 metal kernel can be viewed as a tetracapped truncated tetrahedron (Ag17) surrounded with six W‐shaped Ag5 units. The clusters are homochiral as evidenced by CD measurements. As for the strong CD signals, large contributions are found from the occupied Ag s,p states (superatomic D states) near the Fermi level. Electron counting revealed that these clusters are 18‐electron systems, suggesting they are superatomic clusters. The superatomic nature with a 1S21P61D10 configuration was supported by DFT calculations. This work paves the way of taking AAs as facile chiral induction agents for the synthesis of metal nanoclusters. [ABSTRACT FROM AUTHOR]