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, [Pd(II) (6)O(12)M(8){(CH(3))(2)AsO(2)}(16)(H(2)O)(8)](4+) (M=Ce(IV), Th(IV)), 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 {Pd(6)O(12)}(12−) core that is capped by eight M(IV) ions, resulting in a cationic, cubic assembly {Pd(6)O(12)M(IV) (8)}(20+), which is coordinated by a total of 16 terminal dimethylarsinate and eight water ligands, resulting in the mixed Pd(II)‐Ce(IV)/Th(IV) oxo‐clusters [Pd(II) (6)O(12)M(8){(CH(3))(2)AsO(2)}(16)(H(2)O)(8)](4+) (M=Ce, Pd(6)Ce(8) ; Th, Pd(6)Th(8) ). We have also studied the formation of host‐guest inclusion complexes of Pd(6)Ce(8) and Pd(6)Th(8) 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 CO(2)‐reduction and HCOOH‐oxidation.