Syntheses, Structures, and Electrochemical Properties of Three New Acetate-Functionalized Zirconium-Substituted Germanotungstates: From Dimer to Tetramer.

Under hydrothermal conditions, three new acetate-functionalized zirconium-substituted polyoxometalates, H4Na2[Na6(H2O)22][Zr4(μ3-O)2(OH)2(OAc)2(α-GeW10O37)2]·32H2O (1), H8K3Na5[Zr6(μ3-O)3(OH)3(OAc)(H2O)(β-GeW10O37)3]·20H2O (2), H6K4Na12[{Zr5(μ3-OH)4(OH)2}@{Zr2(OAc)2(α-GeW10O38)2}2]·22H2O (3), were synthesized and characterized. In 1, the sandwiched dimer [Zr4(μ3-O)2(OH)2(OAc)2(α-GeW10O37)2]12- was linked to a hexameric [Na6(H2O)22]6+ cluster to form a 1D chain. In 2, the trimer was constructed from three [β2-GeW10O37]10- units and a new [Zr6O3(OH)3(OAc)(H2O)]14+ cluster. In 3, the tetramer was built by two novel sandwich-type dimers [Zr2(OAc)2(α2-GeW10O38)2]18- and one unique [Zr5(μ3-OH)4(OH)2]14+ core in an approximately orthogonal fashion, showing a staggered tetrahedral polyanion. Also, the electrochemistry and electrocatalytic properties of 3 were studied, exhibiting good catalytic activities toward the reduction of H2O2, BrO3-, and NO2-.