Syntheses and Molecular Structures of Monomeric and Hydrogen-Bonded Dimeric Dawson-Type Trialuminum-Substituted Polyoxotungstates Derived under Acidic and Basic Conditions

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• 作者：Chika Nozaki Kato ; Toshifumi Kashiwagi ; Wataru Unno ; Miyuki Nakagawa ; Hidemitsu Uno
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：May 19, 2014
• 年：2014
• 卷：53
• 期：10
• 页码：4824-4832
• 全文大小：371K
• 年卷期：v.53,no.10(May 19, 2014)
• ISSN：1520-510X

文摘

The syntheses and molecular structures of the two types of 伪-Dawson-type trialuminum-substituted polyoxometalates, [B-伪-H₃P₂W₁₅O₅₉{Al(OH₂)}₃]^{6鈥?/sup> (1) and [B-伪-H₃P₂W₁₅O₅₉{Al(OH)}₂{Al(OH₂)}]₂16鈥?/sup> (2), are described herein. The potassium and cesium salts of 1, K₆[B-伪-H₃P₂W₁₅O₅₉{Al(OH₂)}₃]路14H₂O (K-1), and Cs₆[B-伪-H₃P₂W₁₅O₅₉{Al(OH₂)}₃]路13H₂O (Cs-1) were formed by a stoichiometric reaction in water of trilacunary 伪-Dawson polyoxotungstate with aluminum nitrate under acidic conditions (pH 3). The potassium/sodium and tetramethylammonium/sodium salts of 2, K₁₄Na₂[B-伪-H₃P₂W₁₅O₅₉{Al(OH)}₂{Al(OH₂)}]₂路30H₂O (KNa-2) and [(CH₃)₄N]₁₄Na₂[B-伪-H₃P₂W₁₅O₅₉{Al(OH)}₂{Al(OH₂)}]₂路39H₂O (TMANa-2) were obtained under basic conditions (pH 9). These compounds were characterized by X-ray structure analyses, elemental analyses, thermogravimetric/differential thermal analyses, Fourier transform infrared, and solution 31P, 27Al, and 183W NMR spectroscopy. The polyoxoanion 1 is a monomeric, 伪-Dawson-type structure, resulting in an overall C_3v symmetry, while the polyoxoanion 2 is a hydrogen-bonded dimeric structure, resulting in an overall S₃ symmetry in the solid state. The pH dependence of polyoxoanions 1 and 2 in aqueous solution was also investigated by 31P NMR spectroscopy.}