Preparation of environmental benign nano-structured catalysts composed of clay and metal complexes

以联吡啶和钴衍生物为柱状络合物，通过简单的阳离子交换法制备了新型纳米结构粘土，并用FT-IR、X射线衍射仪、扫描电子显微镜、透射电子显微镜和高分辨固体核磁共振对其进行了表征。用CHN分析、UV-Vis、TG-DTA等方法检测了柱状络合物在LiTN中的负载量。粉末X射线衍射测试表明，插层后纳米结构粘土的层间距增大。具有长链烷基链的改性黄铁矿(n&gt；7)表现出与原始黄铁矿相当的锐利衍射峰。粘土层的高结晶度可以通过层中烷基的疏水作用来实现。由X射线衍射法计算得到的纳米粘土的C.S.(间距=层间距(d&lt；001&gt；)-层厚(0.96 nm))与烷基长度(斜率：0.14 nm/CH2)成正比增加。由透射电子显微镜图像估算的纳米结构粘土的层间距与由粉末X射线衍射仪计算的纳米粘土的C.S.很好地吻合。纳米粘土的高分辨固体核磁共振研究表明，粘土中的柱状络合物为全反式构象。合成的柱状络合物和纳米粘土用于催化加氢和环氧化反应。对于柱状络合物，除[Rh(COD)C23-bpy]ClO4外，其催化活性随着烷基链长的增加而降低。相反，纳米粘土的活性随着纳米粘土的C.S.的增加而增加。此外，在纳米结构粘土中观察到了衬底的形状选择性，层间距与立体选择性明显相关。此外，我们还发现纳米结构粘土在加氢反应中是可回收的催化剂。

Novel nano-structured composites were synthesized from clays and pillar complexes with long alkyl spacers by simple cation exchange methods, where pillar complexes were rhodium(I) bipyridines and cobalt porphyrins derivatives.The nano-structured clays were characterized by FT-IR,XRD,SEM,TEM and high-resolution solid state NMR. The loading amount of pillar complexes into LiTN was detected by CHN analysis, UV-vis, and TG-DTA. The powder XRD measurements revealed that the basal spacing of the nano-structured clay was expanded after the intercalation. The modified taeniolites with long alkyl chains (n>7) showed sharp diffraction peaks comparable to the original taeniolite. The high crystallinity of clay layers can be achieved by the hydrophobic interaction of alkyl groups in the layers. The C.S.(clearance space=basal spacing (d_<001>)-thickness of layer (0.96 nm)) of the nano-structured clays calculated from XRD increases in proportional to the length of alkyl groups (slope : 0.14 nm/CH_2). The interlayer space estimated from TEM image of the nano-structured clays is well consistent to the C.S.calculated from the powder XRD measurement. High-resolution solid-state ^<13>C NMR study for nano-structured clays elucidated the conformation of the pillar complexes in the clay to be all-trans.Synthesized pillar complexes and nano-structured clays were used for the catalytic hydrogenation reactions and epoxidation of olefins. In case of pillar complexes, catalytic activity was decreased with increasing the alkyl chain length except for [Rh(COD)C23-bpy]ClO_4. On the contrary, the activity of the nano-structured clays increased with C.S.of the nano-structured clays. Moreover, shape selectivity of the substrate was observed fro the nano-structured clays and the interlayer space was clearly related to the stereo selectivity. Furthermore, we found that nano-structured clays were recyclable catalysts in hydrogenation.