Abstract
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.