Polyanionic Clusters [M(P4Mo6)2] (M = Ni, Cd) as Effective Molecular Catalysts for the Electron-Transfer Reaction of Ferricyanide to Ferrocyanide

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• 作者：Weijie Wang ; Zhangang Han ; Xiaoxiao Wang ; Chuan Zhao ; Haitao Yu
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：July 5, 2016
• 年：2016
• 卷：55
• 期：13
• 页码：6435-6442
• 全文大小：735K
• 年卷期：0
• ISSN：1520-510X

文摘

Three polyanion-containing supramolecular hybrids, (H₂bpp)₆{Ni[Mo^V₆O₁₃(OH)₂(HPO₄)₃(H₂PO₄)]₂}₂·13H₂O [1; bpp = 1,3-bis(4-pyridyl)propane], (H₂bpp)₅{Cd[Mo^V₆O₁₅(HPO₄)₃(H₂PO₄)]₂}{Cd[Mo^V₆O₁₅(HPO₄)₄]₂}·10H₂O (2), (H₂bpp)₂[Cd(H₂O)Cd(H₂O)₂]₂{Cd[Mo^V₆O₁₂(OH)₃(HPO₄)₂(PO₄)₂]₂}·8H₂O (3), have been synthesized and characterized. The inorganic moieties in 1–3 belong to the reduced {M[P₄Mo^V₆X₃₁]₂}ⁿ⁻ (M = Ni, Cd) clusters. Three supramolecular hybrids exhibit reversible multiple electron-transfer behaviors and have been used as heterogeneous molecular catalysts for the reduction of ferricyanide (Fe^III) to ferrocyanide (Fe^II) with Na₂S₂O₃ as a reductant. The experimental results indicate that hybrid materials 1–3 have higher catalytic activity toward the reaction. These low-cost catalysts can effectively decrease the activation energy of this reaction. These values are calculated to be 25.35 kJ·mol^–1 for hybrid 2, 84.11 kJ·mol^–1 for hybrid 1, and 83.14 kJ·mol^–1 for hybrid 3. The reaction mechanism is subjected to a surface-catalytic process.