Orienting zeolite L microcrystals with a functional linker.
Orienting zeolite L microcrystals with a functional linker.
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DOI：
10.1002/anie.200905354
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发表时间：
2010-02
影响因子：
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通讯作者：
Yu Wang;Huanrong Li;Yu Feng;Hongjie Zhang;G. Calzaferri;T. Ren
中科院分区：
文献类型：
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作者：
Yu Wang;Huanrong Li;Yu Feng;Hongjie Zhang;G. Calzaferri;T. Ren
由沸石和介孔二氧化硅形成的一维通道材料是制备和研究有层次组织的无机-有机杂化材料的有吸引力的宿主，从分子尺度到宏观尺度呈现连续有序。[1-4]在我们的大部分实验中，我们一直使用沸石L （ZL）作为宿主。ZL晶体以六边形对称排列的严格平行通道为特征。无色晶体的大小和纵横比可以在很宽的范围内调节。他们的一维频道可以被合适的客人填满。宿主结构施加的几何约束导致通道中客体的超分子组织。染料在ZL通道内的超分子组织是组织的第一阶段。它允许在染料负载ZL晶体的体积内收集光，也允许无辐射能量传输到圆柱体末端或通道中心。在这些主客体材料中观察到一维激发-能量输运组织的第二阶段是将外部受体或供体stopcock荧光团耦合到ZL通道的末端，然后可以捕获或注入电子激发能。组织的第三阶段是通过旋塞中间体将材料连接到外部装置上。[1,3]在器件化学中，高度的超分子组织对于获得所需的宏观性质是很重要的。实现这种组织的一种可能性是将沸石晶体控制组装成定向结构和制备单向材料。首先用沸石A制备了纳米到微米尺寸的致密单层沸石晶体，同时也报道了第一次在瓶中制备单层沸石晶体。[6,7]制备具有致密填料的稳定取向沸石单层的重要步骤是通过离子键和氢键固定将晶体共价结合到底物[8]上定向ZL单层膜的微接触转移印刷最近有报道。沸石晶体的成功组装在很大程度上取决于具有窄粒度分布和明确的形态的晶体的可用性。正如我们所讨论的，六边形ZL晶体可以用几种方式组装。然而，只有在制备单分子层期间自由通道开口未被堵塞或损坏的情况下，才有可能随后将来宾插入通道并添加旋塞。如果成功，该过程将导致具有激励特性的材料，例如电子激发能仅在一个方向上转移。首次实现了具有这种单向电子激发能输运性质的材料，并证明了在衬底上制备相应的沸石单层的方法的改进，我们称之为c-取向开放通道单层（c-ocMLs）
One-dimensional channel materials as formed by some zeolites and mesoporous silicas are attractive hosts for the preparation and investigation of hierarchically organized inorganic–organic hybrid materials, presenting a successive ordering from the molecular up to the macroscopic scale.[1–4] We have been using zeolite L (ZL) as a host in most of our experiments. ZL crystals feature strictly parallel channels arranged in a hexagonal symmetry. The size and aspect ratio of the colorless crystallites can be tuned over a wide range. Their one-dimensional channels can be filled with suitable guests. Geometrical constraints imposed by the host structure lead to supramolecular organization of the guests in the channels. The supramolecular organization of dyes inside the ZL channels is the first stage of organization. It allows light harvesting within the volume of a dye-loaded ZL crystal and also allows radiationless energy transport to either the cylinder ends or to the center of the channel. One-dimensional excitation-energy transport has been observed in these guest–host materials.[5] The second stage of organization is the coupling of an external acceptor or donor stopcock fluorophore to the ends of the ZL channels, which can then trap or inject electronic excitation energy. The third stage of organization is achieved by interfacing the material to an external device through a stopcock intermediate.[1, 3] In device chemistry, a high degree of supramolecular organization is important for attaining the desired macroscopic properties. A possibility for achieving such organization is the controlled assembly of the zeolite crystals into oriented structures and the preparation of monodirectional materials. The preparation of dense monolayers of zeolite crystals in the nanometer to micrometer size regime was first accomplished with zeolite A, for which the first ship-in-abottle synthesis on a monolayer was also reported.[6, 7] An important step in the preparation of stable oriented zeolite monolayers with dense packing was introduced by covalently binding the crystals to a substrate,[8] by using ionic linkage,[9] and by hydrogen-bond fixation.[10] Microcontact transfer printing of oriented ZL monolayers has recently been reported.[11]The successful assembly of zeolite crystals largely depends on the availability of crystals with a narrow particle size distribution and well-defined morphology. Hexagonal ZL crystals can be assembled in several ways, as we have discussed. Subsequent insertion of guests into the channels and addition of stopcocks is, however, only possible if the free channel openings are not blocked or damaged during the preparation of the monolayer. If successful, the procedure leads to materials with exciting properties, such as transfer of electronic excitation energy in one direction only. First materials with such unidirectional electronic excitation energy transport properties have been realized,[12] and improvement of the methods for preparing corresponding zeolite monolayers on a substrate, which we call c-oriented open-channel monolayers (c-ocMLs), has been demonstrated.[13]