Hierarchical\nAssembly of High-Nuclearity Copper(I)\nAlkynide Nanoclusters: Highly Effective CO<sub>2</sub> Electroreduction\nCatalyst toward Hydrocarbons

The\npursuit of precision in the engineering of metal nanoparticle\nassemblies has long fascinated scientists, but achieving atomic-level\naccuracy continues to pose a significant challenge. This research\nsheds light on the hierarchical assembly processes of two high-nuclearity\nCu(I) nanoclusters (NCs). By employing a multiligand cooperative stabilization\nstrategy, we have isolated a series of thiacalix[4]arene (TC4A)/alkynyl\ncoprotected Cu(I) NCs (<b>Cu</b><sub><i>x</i></sub>, where <i>x</i> = <b>9</b>, <b>13</b>, <b>17</b>, <b>22</b>). These NCs are intricately coassembled\nfrom the fundamental building units of {Cu<sub>4</sub>(TC4A)} and\nalkynyl-stabilized Cu<sub>5</sub>L<sub>6</sub> in various ratios.\nBy capturing active anion templates such as O<sup>2–</sup>,\nCl<sup>–</sup>, or C<sub>2</sub><sup>2–</sup> that are\ngenerated in situ, we have further explored the secondary structural\nself-assembly of these clusters. <b>Cu</b><sub><b>13</b></sub> serves as a secondary assembly module for constructing <b>Cu</b><sub><b>38</b></sub> and <b>Cu</b><sub><b>43</b></sub>, which exhibit the highest nuclearity reported to\ndate among Cu(I) NCs encased in macrocyclic ligands. Notably, <b>Cu</b><sub><b>38</b></sub> demonstrates an impressive Faradaic\nefficiency of 62.01% for hydrocarbons at −1.57 V vs RHE during\nCO<sub>2</sub> electroreduction, with 34.03% for C<sub>2</sub>H<sub>4</sub> and 27.98% for CH<sub>4</sub>. This performance establishes\nit as an exceptionally rare, large, atomically precise metal NC (nuclearity\n>30) capable of catalyzing the formation of highly electro-reduced\nhydrocarbon products. Our research has introduced a new approach for\nconstructing high-nuclearity Cu(I) NCs through a hierarchical assembly\nmethod and investigating their potential in the electrocatalytic transformation\nof CO<sub>2</sub> into hydrocarbons.