title: Synergistic combination of multi-Zr(IV) cations and lacunary Keggin germanotungstates leading to a gigantic Zr24-cluster-substituted polyoxometalate.
abstract: 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.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Huang
authors.forename: Sa-Sa
authors.initials: SS
authors.lastname: Wang
authors.forename: Jun-Wei
authors.initials: JW
authors.lastname: Zhao
authors.forename: Lin
authors.initials: L
authors.lastname: Cheng
authors.forename: Guo-Yu
authors.initials: GY
authors.lastname: Yang
mesh_terms: D002384:Catalysis; D002412:Cations; D005857:Germanium / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D017973:Tungsten Compounds / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D002412:Cations; D017973:Tungsten Compounds; D005857:Germanium; D015040:Zirconium