Discrete, Cationic Palladium(II)‐Oxo Clusters via f‐Metal Ion Incorporation and their Macrocyclic Host‐Guest Interactions with Sulfonatocalixarenes

We report on the discovery of the first two examples of cationic palladium(II)‐oxo clusters (POCs) containing f‐metal ions, [PdII6O12M8{(CH3)2AsO2}16(H2O)8]4+ (M=CeIV, ThIV), and their physicochemical characterization in the solid state, in solution and in the gas phase. The molecular structure of the two novel POCs comprises an octahedral {Pd6O12}12− core that is capped by eight MIV ions, resulting in a cationic, cubic assembly {Pd6O12MIV8}20+, which is coordinated by a total of 16 terminal dimethylarsinate and eight water ligands, resulting in the mixed PdII‐CeIV/ThIV oxo‐clusters [PdII6O12M8{(CH3)2AsO2}16(H2O)8]4+ (M=Ce, Pd6Ce8; Th, Pd6Th8). We have also studied the formation of host‐guest inclusion complexes of Pd6Ce8 and Pd6Th8 with anionic 4‐sulfocalix[n]arenes (n=4, 6, 8), resulting in the first examples of discrete, enthalpically‐driven supramolecular assemblies between large metal‐oxo clusters and calixarene‐based macrocycles. The POCs were also found to be useful as pre‐catalysts for electrocatalytic CO2‐reduction and HCOOH‐oxidation. The first cationic palladium(II)‐oxo clusters (POCs) containing f‐metal ions, [PdII6O12M8{(CH3)2AsO2}16(H2O)8]4+ (M=CeIV, ThIV), have been structurally characterized and utilized as electrocatalysts. These POCs exhibit host‐guest interactions with 4‐sulfocalix[n]arenes (n=4, 6, 8), resulting in the first examples of discrete, enthalpically‐driven supramolecular assemblies between calixarene‐based macrocycles and large metal‐oxo clusters.