Hierarchical Assembly of High-Nuclearity Copper(I) Alkynide Nanoclusters: Highly Effective CO₂ Electroreduction...

The pursuit of precision in the engineering of metal nanoparticle assemblies has long fascinated scientists, but achieving atomic-level accuracy continues to pose a significant challenge. This research sheds light on the hierarchical assembly processes of two high-nuclearity Cu(I) nanoclusters (NCs). By employing a multiligand cooperative stabilization strategy, we have isolated a series of thiacalix[4]arene (TC4A)/alkynyl coprotected Cu(I) NCs (Cu, where x = 9, 13, 17, 22). These NCs are intricately coassembled from the fundamental building units of {Cu₄(TC4A)} and alkynyl-stabilized Cu₅L₆ in various ratios. By capturing active anion templates such as O^2-, Cl^-, or C₂^2- that are generated in situ, we have further explored the secondary structural self-assembly of these clusters. Cu serves as a secondary assembly module for constructing Cu and Cu, which exhibit the highest nuclearity reported to date among Cu(I) NCs encased in macrocyclic ligands. Notably, Cu demonstrates an impressive Faradaic efficiency of 62.01% for hydrocarbons at -1.57 V vs RHE during CO₂ electroreduction, with 34.03% for C₂H₄ and 27.98% for CH₄. This performance establishes it as an exceptionally rare, large, atomically precise metal NC (nuclearity >30) capable of catalyzing the formation of highly electro-reduced hydrocarbon products. Our research has introduced a new approach for constructing high-nuclearity Cu(I) NCs through a hierarchical assembly method and investigating their potential in the electrocatalytic transformation of CO₂ into hydrocarbons.