Alkynyl‐Protected Chiral Bimetallic Ag<sub>22</sub>Cu<sub>7</sub> Superatom with Multiple Chirality Origins
Guocheng Deng, Kangjae Lee, Hongwen Deng, Sami Malola, Megalamane S. Bootharaju, Hannu Häkkinen, Nanfeng Zheng, Taeghwan Hyeon
Abstract
Abstract Understanding the origin of chirality in the nanostructured materials is essential for chiroptical and catalytic applications. Here we report a chiral AgCu superatomic cluster, [Ag 22 Cu 7 (C≡CR) 16 (PPh 3 ) 5 Cl 6 ](PPh 4 ), Ag 22 Cu 7 , protected by an achiral alkynyl ligand (HC≡CR: 3,5‐bis(trifluoromethyl)phenylacetylene). Its crystal structure comprises a rare interpenetrating biicosahedral Ag 17 Cu 2 core, which is stabilized by four different types of motifs: one Cu(C≡CR) 2 , four −C≡CR, two chlorides and one helical Ag 5 Cu 4 (C≡CR) 10 (PPh 3 ) 5 Cl 4 . Structural analysis reveals that Ag 22 Cu 7 exhibits multiple chirality origins, including the metal core, the metal‐ligand interface and the ligand layer. Furthermore, the circular dichroism spectra of R/S‐Ag 22 Cu 7 are obtained by employing appropriate chiral molecules as optical enrichment agents. DFT calculations show that Ag 22 Cu 7 is an eight‐electron superatom, confirm that the cluster is chirally active, and help to analyze the origins of the circular dichroism.