A Trinuclear Zr-Substituted Decanuclear Hetero-Metal Sandwich Tungstoantimonate: Synthesis, Structure and Properties

A new trinuclear Zr⁴⁺ cluster substituted decanuclear hetero-metal sandwich tungstoantimonate aggregate [H₂N(CH₃)₂]₇Na₃H₅{[Zr₃(OAc)W₇(H₂O)O₂₅][B-α-SbW₉O₃₃]₂}·22H₂O (1) has been synthesized under hydrothermal condition by reacting [B-α-SbW₉O₃₃]^9– precursor, ZrOCl₂·8H₂O, Na₂WO₄·2H₂O and dimethylamine hydrochloride in sodium acetate buffer (pH = 4.8) and structurally characterized by elemental analyses, IR spectrum, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. The structure unit of 1 consists of a new sandwich tungstoantimonate (TA) unit {[Zr₃(OAc)W₇(H₂O)O₂₅][B-α-SbW₉O₃₃]₂}^15– constituted by two trivacant Keggin [B-α-SbW₉O₃₃]^9– fragments linked through an unseen hetero-metal cluster [Zr₃(OAc)W₇(H₂O)O₂₅]³⁺. In addition, the polyoxoanion can also be described as two trivacant Keggin [B-α-SbW₉O₃₃]^9– fragments and one divacant Lindqvist [W₄O₁₆]^8– linked by a hexanuclear hetero-metal cluster [Zr₃(OAc)W₃(H₂O)O₉]¹¹⁺ link. Moreover, the solid-state electrochemistry and electrocatalytic performances of 1 have been measured in 0.5 mol L^–1 Na₂SO₄ + H₂SO₄ aqueous solution, and the results show that 1 illustrates comparatively apparent catalytic activities toward the BrO₃^– and H₂O₂ reduction.