Thomas S. M., Bertrand J. A., Occelli M. L., Huggins F., Gould S. A. C.
Zeolites and Clays Program, GTRI, Georgia Institute of Technology, Atlanta, Georgia 30332-0827, Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, University of Kentucky, Lexington, Kentucky 40506-0043, and W. M. Keck Science Center, Claremont Colleges, Claremont, California 91711.
Inorg Chem. 1999 May 3;38(9):2098-2105. doi: 10.1021/ic981127g.
Expanded clays bipillared with Al(13)O(4)(OH)(24)(H(2)O)(12) ions and with hexameric Cu complexes such as M(&mgr;-OH)Cu(&mgr;-OCH(2)CH(2)NEt(2))(ClO(4))(3), or with M(&mgr;-OH)Cu(&mgr;-OCH(2)CH(2)NEt(2))(PF(6))(3) where M = Fe, Al, Ga, form microporous materials whose stability and microporosity depend mainly on the identity of the hexamer central metal atom. In fact, a general decrease in thermal stability, interlamellar heights, surface areas, and pore volumes was noted when, in the (Cu,M) hexamer, M changed from gallium to aluminum to iron. Mossbauer results have indicated that only Fe(3+) in octahedral coordination is present in the iron-containing bi-PILC samples (bi-PILC = bipillared interlayered clays). It is believed that metals such as Fe(3+) and Cu(2+) can interact with the interlamellar Keggin ions thereby decreasing the stability of the alumina pillars. In contrast, the intermediate Al(13)-PILC structure is least affected when the more stable Cr complex is used. Bi-PILC materials containing 2.7-3.4% Cr stable to 500 degrees C have been obtained. The low polarity of the chosen solvent (acetonitrile) appears to inhibit the back-exchange of the intermediate PILC's Keggin ions with the hexameric Cu complexes. Elemental analysis together with XRD results suggests that the primary intercalation pathway was diffusion or ion exchange when Cr(&mgr;-OCH(3))(&mgr;-OCH(2)CH(2)NEt(2))CuCl or M(&mgr;-OH)Cu(&mgr;-OCH(2)CH(2)NEt(2))(ClO(4))(3), respectively, was used. In all preparations, bi-PILC were produced containing complexes that suffered ligand losses during the synthesis reaction. Molecular scale AFM images have shown that these complexes can be found also outside the clay interlamellar space.
用Al(13)O(4)(OH)(24)(H(2)O)(12)离子以及六聚体铜配合物（如M(&mgr;-OH)Cu(&mgr;-OCH(2)CH(2)NEt(2))(ClO(4))(3)或M(&mgr;-OH)Cu(&mgr;-OCH(2)CH(2)NEt(2))(PF(6))(3)，其中M = Fe、Al、Ga）支撑的膨胀黏土形成微孔材料，其稳定性和微孔性主要取决于六聚体中心金属原子的种类。事实上，当在（Cu,M）六聚体中M从镓变为铝再变为铁时，热稳定性、层间高度、表面积和孔体积普遍下降。穆斯堡尔谱结果表明，含铁双柱撑层状黏土（双柱撑层状黏土 = bipillared interlayered clays）样品中仅存在八面体配位的Fe(3+)。据信，Fe(3+)和Cu(2+)等金属可与层间的Keggin离子相互作用，从而降低氧化铝柱撑的稳定性。相比之下，当使用更稳定的Cr配合物时，中间的Al(13)-柱撑层状黏土结构受影响最小。已获得在500℃下稳定的含2.7 - 3.4% Cr的双柱撑层状黏土材料。所选溶剂（乙腈）的低极性似乎抑制了中间柱撑层状黏土的Keggin离子与六聚体铜配合物的反向交换。元素分析以及XRD结果表明，当分别使用Cr(&mgr;-OCH(3))(&mgr;-OCH(2)CH(2)NEt(2))CuCl或M(&mgr;-OH)Cu(&mgr;-OCH(2)CH(2)NEt(2))(ClO(4))(3)时，主要的插层途径是扩散或离子交换。在所有制备过程中，生成的双柱撑层状黏土都含有在合成反应过程中发生配体损失的配合物。分子尺度的原子力显微镜图像表明，这些配合物在黏土层间空间之外也能找到。
