A Homoleptic Alkynyl‐Ligated [Au<sub>13</sub>Ag<sub>16</sub>L<sub>24</sub>]<sup>3−</sup> Cluster as a Catalytically Active Eight‐Electron Superatom
Zhaoxian Qin, Sachil Sharma, Chong‐Qing Wan, Sami Malola, Wenwu Xu, Hannu Häkkinen, Gao Li
Abstract
Abstract A new alkynylated cluster [Au 13 Ag 16 (C 10 H 6 NO) 24 ] 3− is prepared by a NaBH 4 mediated reduction method. The AuAg clusters are confirmed by sophisticated characterization techniques. It has a unique “Au center @Ag 12 @Au 12 Ag 4 ” metal framework which is protected by 24 atypical alkyne ligands L (L=C 10 H 6 NO). The ligands construct a unique type of motif L‐(Ag)‐Au‐(Ag)‐L at the cluster interface, where the alkyne (C≡C) group of each L was linked by sharing an Au atom through the σ bonds and each C≡C group was discretely connected to a chemically different Ag atom (Ag icosahedral /Ag cap ) through π bonds. The electronic and optical properties of [Au 13 Ag 16 L 24 ] 3− were studied. DFT characterized the cluster as a clear 8‐electron superatom, and peaks in the optical absorption spectrum were interpreted in terms of the P and D superatom states. The supported Au 13 Ag 16 L 24 /CeO 2 catalyst exhibited high catalytic activity and selectivity towards the A 3 ‐coupling reaction involving benzaldehyde, diethylamine, and phenylacetylene.