The ITQ-37 mesoporous chiral zeolite
The ITQ-37 mesoporous chiral zeolite
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DOI：
10.1038/nature07957
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发表时间：
2009-04-30
期刊：
影响因子：
64.8
通讯作者：
Zou, Xiaodong
中科院分区：
文献类型：
--
作者：
Sun, Junliang;Bonneau, Charlotte;Zou, Xiaodong
具有填充微孔和中孔材料之间的差距的孔尺寸的结晶分子筛的合成是基本的和工业上感兴趣的问题（1-3）。具有超大孔和手性骨架的沸石材料的制备将允许许多新的应用。在这个方向上的两个重要步骤包括ITQ-33（具有18 × 10 × 10环窗口的稳定沸石）的合成（4）和SU-32（具有固有手性沸石结构并且其中每个晶体仅表现出一种手性）的合成（5）。在这里，我们提出了一个锗硅酸盐沸石（ITQ-37）特大30环窗口。其结构通过在电荷翻转算法（6）中结合选区电子衍射（SAED）和粉末X射线衍射（PXRD）来确定。该框架遵循SrSi 2（srs）最小网（7）并形成两个独特的腔，每个腔与三个其他腔连接以形成回转通道系统。这些空穴构成了骨架的对映体srs网。ITQ-37是第一个具有单螺旋通道的手性沸石。在所有现有的4-配位晶体氧化物骨架中，它具有最低的骨架密度（每1，000埃10.3个T原子），相应的二氧化硅多晶型物的孔体积为0.38 cm（3）g（-1）。
The synthesis of crystalline molecular sieves with pore dimensions that fill the gap between microporous and mesoporous materials is a matter of fundamental and industrial interest(1-3). The preparation of zeolitic materials with extralarge pores and chiral frameworks would permit many new applications. Two important steps in this direction include the synthesis(4) of ITQ-33, a stable zeolite with 18 x 10 x 10 ring windows, and the synthesis(5) of SU-32, which has an intrinsically chiral zeolite structure and where each crystal exhibits only one handedness. Here we present a germanosilicate zeolite (ITQ-37) with extralarge 30-ring windows. Its structure was determined by combining selected area electron diffraction ( SAED) and powder X-ray diffraction (PXRD) in a charge-flipping algorithm(6). The framework follows the SrSi2 (srs) minimal net(7) and forms two unique cavities, each of which is connected to three other cavities to form a gyroidal channel system. These cavities comprise the enantiomorphous srs net of the framework. ITQ-37 is the first chiral zeolite with one single gyroidal channel. It has the lowest framework density (10.3 T atoms per 1,000 angstrom(3)) of all existing 4-coordinated crystalline oxide frameworks, and the pore volume of the corresponding silica polymorph would be 0.38 cm(3) g(-1).