Scientists construct M29 cluster model catalyst

Recently, a group led by Prof. Li Gao from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in collaboration with Prof. Wan Chongqing from Capital Normal University and Prof. Hannu Hakkinen from University of Jyvaskyla, synthesized a novel atomically precise AuAg cluster with special structure, which is exploited as a model catalyst for A3-coupling reactions.

This work was published in Angewandte Chemie International Edition on Sept. 30.

The scientists prepared a brand new alkynylated cluster [Au₁₃Ag₁₆(C₁₀H₆NO)₂₄]₃^- via the NaBH₄-mediated reduction method, and confirmed the AuAg clusters by various sophisticated characterization techniques. They found that the unique metal framework of Au_center@Ag₁₂@Au₁₂Ag₄ was protected by 24 atypical alkyne ligands L (L = C₁₀H₆NO).

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 through π bonds.

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 Au₁₃Ag₁₆L₂₄/CeO₂ catalyst exhibited high catalytic activity and selectivity towards the A3-coupling reaction involving benzaldehyde, diethylamine and phenylacetylene.