A mixed-addenda Nb/W polyoxometalate containing dimeric Dawson subunit: Synthesis, structure, and characterization

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• 作者：Yuanhang Ren ; Yichen Hu ; Yucheng Shan ; Zuping Kong ; Min Gu ; Bin Yue ; Heyong He
• 关键词：Polyoxometalates ; Nb/W mixed-addenda ; Dawson type ; Dimeric unit
• 刊名：Inorganic Chemistry Communications
• 出版年：February, 2014
• 年：2014
• 卷：40
• 期：Complete
• 页码：108-111
• 全文大小：597 K

文摘

A mixed-addenda Nb/W polyoxometalates, K₄Na₄[H₆P₂W₁₂Nb₄O₅₉(NbO₂)₂]₂ 路 48H₂O (1), has been isolated under acidic condition. The single crystal structural analysis showed that the six vacant sites of the lacunary {P₂W₁₂} precursor are occupied by six Nb atoms, two at the polar sites and four at the equatorial sites to form a {P₂W₁₂Nb₆} mixed-addenda subunit. Two {P₂W₁₂Nb₆} subunits are joined together in an inversion mode by two Nb-O-Nb bridges from the Nb atoms at equatorial sites to form a dimeric unit, which can be considered as a Nb₁₂ core wrapped by two lacunary {P₂W₁₂} polyoxoanions. It is notable that the terminal peroxo groups bonded niobium atoms in the Nb₁₂ core are only partially eliminated during the formation of the dimeric unit.