Exposing the Delocalized Cu−S π Bonds on the Au₂₄Cu₆(SPh<i>t</i>Bu)₂₂ Nanocluster and Its Application in Ring‐Opening Reactions

Abstract

Bimetallic nanomaterials are of major importance in catalysis. A Au-Cu bimetallic nanocluster was synthesized that is effective in catalyzing the epoxide ring-opening reaction. The catalyst was analyzed by SCXRD and ESI-MS and found to be Au₂₄ Cu₆ (SPhtBu)₂₂ (Au₂₄ Cu₆ for short). Six copper atoms exclusively occupy the surface positions in two groups with three atoms for each, and each group was bonded with three thiolate ligands to give a planar motif reminiscent of a benzene ring. In the epoxide-ring opening reaction, Au₂₄ Cu₆ exhibited superior catalytic activity compared to other homometallic and Au-Cu alloy NCs, such as Au₂₅ and Au_38-x Cu_x . Control experiments and DFT calculations revealed that the π conjugation among the Cu-S bonds played a pivotal role. This study demonstrates a unique π conjugation established among the Cu-S bonds as a critical structural motif in the nanocluster, which facilitates the catalysis of a ring-opening reaction.