A Series of Arsenotungstates Based on the [HAs2W8O31]7鈥?/sup> Building Block: Syntheses by Control of the Reaction Process

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• 作者：Lei Yang ; Xiang Ma ; Pengtao Ma ; Jiai Hua ; Jingyang Niu
• 刊名：Crystal Growth & Design
• 出版年：2013
• 出版时间：July 3, 2013
• 年：2013
• 卷：13
• 期：7
• 页码：2982-2989
• 全文大小：519K
• 年卷期：v.13,no.7(July 3, 2013)
• ISSN：1528-7505

文摘

A series of arsenotungstates formulated as (H₂en)_3.5[HAs₂W₈O₃₁]路6H₂O (1), Na_0.5(H₂en)_6.5{Ni₃(en)[B-伪-AsW₉O₃₄][B-尾-AsW₈O₃₁]}Cl_1.5路9H₂O (2), and [H₂en]₄{[Ni₄(Hen)₂][B-伪-AsW₉O₃₄]₂}路5H₂O (3) have been sequentially synthesized by controlling the reaction process. First, 1 was synthesized in an aqueous medium by the reaction of NiCl₂ and NaAsO₂ with Na₂WO₄, then colorless crystals of 1 transformed to yellow-green crystals of 2 for the further development of slow solvent evaporation, and, finally, yellow crystals of 3 generated over a sufficiently long time of solvent evaporation. 3 can also be hydrothermally synthesized in three different routes. Notably, 1 presents a [HAs₂W₈O₃₁]^{7鈥?/sup> building block, 2 exhibits an asymmetric sandwich-type arsenotungstate encapsulating two nonequivalent Keggin fragments [B-伪-AsW₉O₃₄]9鈥?/sup> and [B-尾-AsW₈O₃₁]9鈥?/sup>, and 3 is composed of two [B-伪-AsW₉O₃₄]9鈥?/sup> units sandwiching a tetranickel cluster. Their structural difference indicates that controlling the reaction process plays a key role in the structures and topologies of these complexes}