A Homoleptic Alkynyl‐Ligated [Au13Ag16L24]3‐ Cluster as a Catalytically Active Eight‐Electron Superatom

Abstract

A brand new alkynylated cluster [Au 13 Ag 16 (C 10 H 6 NO) 24 ] 3- is prepared by NaBH 4 mediated reduction method. The AuAg clusters are confirmed by various sophisticated characterization techniques. It manifested the unique metal framework of “Au center @Ag 12 @Au 12 Ag 4 ” is protected by 24 atypical alkyne ligands L (L = C 10 H 6 NO). The ligands were found to 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 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 in detail. DFT characterized the cluster as a clear 8-electron superatom, and peaks in the optical absorption spectrum were successfully 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.