Substituent‐Effect Directed Assembly of 95‐Nuclear 3d‐4f Cluster { Co 39 RE 56 } with Potential for Photocatalytic CO 2 Reduction to CO

Comprehensive Summary The design and synthesis of structurally robust high‐nuclearity 3d‐4f clusters suitable for the photocatalytic reduction of CO 2 have consistently presented formidable challenges. In this study, we achieved a notable enhancement in the solubility of ligands in methanol by judiciously modifying the substituents on the N‐donor of iminodiacetic acid ligand. This advancement empowered us to synthesize an innovative family of 3d‐4f coordination clusters comprising 95 metal centers, specifically {Co 39 RE 56 } (where RE = La ( 1 ), Pr ( 2 ), and Nd ( 3 )), under solvothermal conditions. To our knowledge, this represents one of the rare instances within high‐nuclearity Co‐RE clusters. Their exceptional solution stability and potential multi‐site active centers render these clusters highly promising candidates for photocatalytic CO 2 reduction. Notably, cluster 1 achieves a comparable CO production rate (2887.2 μmol·g −1 ·h −1 ) and selectivity (94.4%) to those of many existing catalysts. Spin‐polarized density functional theory calculations were conducted to elucidate the mechanisms underlying catalytic reactions. This work provides new insights into the design and assembly of nanoscale heterometallic 3d‐4f cluster catalysts.