2D hydrogen-bonded square-grid coordination networks with a substitution-active metal site.
2D hydrogen-bonded square-grid coordination networks with a substitution-active metal site.
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DOI：
10.1021/ic052138u
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发表时间：
2006-04
影响因子：
4.6
通讯作者：
K. Takaoka;M. Kawano;T. Hozumi;S. Ohkoshi;M. Fujita
中科院分区：
文献类型：
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作者：
K. Takaoka;M. Kawano;T. Hozumi;S. Ohkoshi;M. Fujita
报道了乙二醇侧链棒状配体组成的二维配位网络的制备和性质(1)。合成了两个二维配位网络[[Co(1)2(H2O)2](NO3)2.1.5H2O]n和[[Ni(1)2(H(2)O)2](NO3)2.1.5H2O]n，并用单晶X射线衍射仪、TG、DSC、UV-Vis光谱和磁性测量对其进行了表征。结构分析表明，由乙二醇链组成的无限一维氢键阵列有助于稳定二维配位骨架，保持取代活性金属中心的环境不变。它们比类似的在配体上没有乙二醇链的方形网格配位网络更稳定。我们还成功地在钴(II)和镍(II)离子上以单晶到单晶的方式直接观察到可逆的顶端配体交换反应，这是因为该骨架具有相当的稳定性和适度的柔性。含钴配位网络晶体的显色行为与温度有关。结晶学和光谱研究表明，晶体的颜色变化是由于水与金属钴上的硝酸根离子之间的配体交换过程所致。磁性测量表明钴(II)离子之间存在较弱的反铁磁性最近邻自旋耦合。
Reported here is the preparation and property of 2D coordination networks composed of rodlike ligands with ethylene glycol side chains (1). Two 2D coordination networks, [[Co(1)2(H2O)2](NO3)2.1.5H2O]n and [[Ni(1)2(H(2)O)2](NO3)2.1.5H2O]n, have been synthesized and characterized by single-crystal X-ray diffraction, TG, DSC, UV-vis spectroscopy, and magnetic measurements. The structural analyses clarified that infinite 1D hydrogen-bond arrays composed of ethylene glycol chains contribute to the stabilization of 2D coordination frameworks, keeping the environment of substitution-active metal sites unchanged. They are more stable than a similar square-grid coordination network that does not possess an ethylene glycol chain on the ligand. We also succeeded in the direct observation of a reversible apical-ligand-exchange reaction at the cobalt(II) and nickel(II) ions in a single-crystal-to-single-crystal fashion because of the considerable stability as well as moderate flexibility of the framework. The cobalt-containing coordination network crystal showed chromic behavior depending on temperatures. Crystallographic and spectroscopic studies revealed that the color change of the crystal was attributed to the ligand-exchange process between H2O and a NO3 anion on the cobalt metal. Magnetic measurements indicated weak antiferromagnetic nearest-neighbor spin coupling between cobalt(II) ions.