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超分子结构[Co（C2O4）3]3-插层镁铝水滑石的组成及热稳定性
COMPOSITION AND THERMAL STABILITY OF SUPRAMOLECULAR ASSEMBLY[Co（C2O4）3]3-INTERCALATED Mg-Al LAYERED DOUBLE HYDROXIDES
【摘要】 以Mg0.67Al0.33（OH）2（NO3-）0.33·0.61H2O水滑石为前驱体,用离子交换法将三草酸合钴酸根([Co（C2O4）3]3-)插入到层状双金属氢氧化物（layered double hydroxides,LDHs）层间,用X射线衍射谱、Fourier变换红外光谱、热重-差热分析和电感偶合等离子体发射光谱等对样品进行表征。结果表明:[Co（C2O4）3]3-可取代层间的No3-组装得到晶体结构良好的[Co（C2O4）3]3--LDHs。[Co（C2O4）3]3--LDHs的层间距为1.008 nm;通过与半经验PM3分子轨道法优化计算得到的[Co（C2O4）3]3-三维尺寸进行比较,推测客体[Co（C2O4）3]3-是沿短轴垂直于层板的方式单层交替排布于层间,与主体层板通过氢键与静电作用形成超分子结构,增加了[Co（C2O4）3]3-的稳定性。
【Abstract】 [Co（C2O4）3]3-pillared Mg-Al layered double hydroxides（LDHs）were successfully assembled by ion-exchange method using Mg0.67Al0.33（OH）2（NO3-）0.30·0.61 H2O as a precursor.The samples thereby obtained were characterized by X-ray diffraction,Fou- tier transform infrared microscopy,thermogravimetric-differential thermal analysis and inductive coupled plasma emission spec- trometry measurements.The results show that the original interlayer nitrate anions of the Mg/Al-LDHs can be replaced by [Co（C2OV4）3]3-,producing[Co（C2O4）3]3-intercalated Mg/Al-LDHs([Co（C2O4）3]3--LDHs)with good crystallinity.The interlayer spacing of the as-synthesized[Co（C2O4）3]3--LDHs is 1.008 nm,and it is compared with a three-dimensional molecular size of [Co（C2O4）3]3-calculated fi’om the PM3 semi-empirical molecular orbital method.The[Co（C2O4）3]3-guests are arranged by an alter- nate and monolayer positioned vertically（along the short axis orientation）between layers.The interaction of the host layers and the guests occurs through hydrogen bonding and electrostatic attraction,confirming that the intercalated LDHs have a supramolecular structure,which increases the thermal stability of[Co（C2O4）3]3-.
【Key words】 layered double hydroxides； intercalation； supramolecular structure； thermal stability；
- 【文献出处】 硅酸盐学报 ,Journal of the Chinese Ceramic Society , 编辑部邮箱 ,2009年01期
- 【分类号】TB321
- 【被引频次】7
- 【下载频次】335