Synergistic Combination of Multi-ZrIV Cations and Lacunary Keggin Germanotungstates Leading to a Gigantic Zr24-Cluster-Substituted Polyoxometalate

Synergistic directing roles of six lacunary fragments resulted in an unprecedented Zr24-cluster substituted poly­(polyoxotungstate) Na10­K22­[Zr24­O22­(OH)10­(H2O)2­(W2­O10­H)2­(GeW9­O34)4­(GeW8­O31)2]·85H2O (Na10K22·1·85H2O), which contains the largest [Zr24O22(OH)10(H2O)2] (Zr24) cluster in all the Zr-based poly­(polyoxometalate)­s to date. The most remarkable feature is that the centrosymmetric Zr24-cluster-based hexamer contains two symmetry-related [Zr12­O11­(OH)5­(H2­O)­(W2­O10H)­(GeW9­O34)2­(GeW8­O31)]16– trimers via six μ3-oxo bridges and was simultaneously trapped by three types of different segments of B-α-GeW9O34, B-α-GeW8O31, and W2O10. The other interesting characteristic is that there are two pairs of intriguing triangular atom alignments: one is composed of the Zr­(2,4,6,8,11) and W21 atoms and the other contains the Ge(1–3), Zr­(3,5,7,9,10,12) and W26 atoms, and the Zr5 atom is inside the triangle; a linking mode is unobserved. The oxygenation reactions of thioethers by H2O2 were evaluated when Na10K22·1·85H2O served as a catalyst. Results show that it is an effective catalyst for oxygenation of thioethers by H2O2. The unique redox property of oxygen-enriched polyoxotungstate fragments and Lewis acidity of the Zr cluster imbedded in Na10K22·1·85H2O provide a sufficient driving force for the catalytic conversion from thioethers to sulfoxides/sulfones.