3D Racemic Microporous Frameworks and 3D Chiral Supramolecular Architectures Based on Evans鈥揝howell-Type Polyoxometalates Controlled by the Temperature

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• 作者：Haiyan An ; Ying Hu ; Lin Wang ; Enlong Zhou ; Fei Fei ; Zhongmin Su
• 刊名：Crystal Growth & Design
• 出版年：2015
• 出版时间：January 7, 2015
• 年：2015
• 卷：15
• 期：1
• 页码：164-175
• 全文大小：737K
• ISSN：1528-7505

文摘

Four new architectures containing [Co<sub>2sub>Mo<sub>10sub>H<sub>4sub>O<sub>38sub>]<sup>6鈥?/sup> polyoxoanion, [Ln(H<sub>2sub>O)<sub>7sub>][Ln(H<sub>2sub>O)<sub>5sub>][Co<sub>2sub>Mo<sub>10sub>H<sub>4sub>O<sub>38sub>]路5H<sub>2sub>O (Ln = Gd 1; Tb 2), and (NH<sub>4sub>)<sub>3sub>[Ln(H<sub>2sub>O)<sub>6sub>][Co<sub>2sub>Mo<sub>10sub>H<sub>4sub>O<sub>38sub>]路6H<sub>2sub>O (Ln = Gd 3; Tb 4) have been synthesized at different temperatures and characterized by elemental analysis, IR and Raman spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Isostructural compounds 1 and 2 obtained at the higher temperature (85 掳C), are built up of Evans鈥揝howell-type polyoxoanions [Co<sub>2sub>Mo<sub>10sub>H<sub>4sub>O<sub>38sub>]<sup>6鈥?/sup>, respectively, linked by Gd<sup>3+sup> or Tb<sup>3+sup> cations to form a 3D racemic framework with 1D zigzag channels. From the topological point of view, the 3D net is a rare binodal 4-connected SrAl<sub>2sub> (sra) topology. As far as we know, compounds 1 and 2 represent the first examples of 3D architectures based on Evans鈥揝howell-type polyoxometalate. Interestingly, the stable 3D microporous compounds exhibit selective adsorption ability: adsorbing water and methanol, as well as excellent photocatalytic activity for organic dye degradation under visible light irradiation. When the reaction temperature was decreased to room temperature (25 掳C), two chiral species 3 and 4 were obtained, with a monosupporting structure composed of one [Co<sub>2sub>Mo<sub>10sub>H<sub>4sub>O<sub>38sub>]<sup>6鈥?/sup> polyoxoanion and one [Ln(H<sub>2sub>O)<sub>6sub>]<sup>3+sup> unit. These chiral monosupporting motifs can be connected by strong hydrogen-bonding interactions to form a 3D chiral supramolecular architecture. They crystallize in the chiral space group P2<sub>1sub>, as conglomerates of two enantiomerically pure crystals. Their absolute configurations were determined by the Flack parameters and solid-state circular dichroism spectroscopy.