Ma Yanhang, Oleynikov Peter, Terasaki Osamu
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
Department of Materials & Environmental Chemistry, Stockholm University, Stockholm SE-10691, Sweden.
Nat Mater. 2017 Jul;16(7):755-759. doi: 10.1038/nmat4890. Epub 2017 May 1.
Chiral crystals can be exploited for applications in enantioselective separation and catalysis. However, the study of chirality at the atomic level in a sub-micrometre-sized crystal is difficult due to the lack of adequate characterization methods. Herein, we present two efficient and practical methods of characterization that are based on electron crystallography. These methods are successfully applied to reveal the handedness of a chiral, zeolite nanocrystal. The handedness is identified through either a comparison of two high-resolution transmission electron microscope images, taken from the same nanocrystal but along different zone axes by tilting it around its screw axis, or the intensity asymmetry of a Bijvoet pair of reflections in a single precession electron-diffraction pattern. These two approaches provide new ways to determine the handedness of small, chiral crystals.
手性晶体可用于对映选择性分离和催化。然而，由于缺乏足够的表征方法，在亚微米尺寸晶体中对原子水平的手性进行研究具有一定难度。在此，我们提出了两种基于电子晶体学的高效实用的表征方法。这些方法成功地应用于揭示手性沸石纳米晶体的旋向性。通过比较从同一纳米晶体沿不同晶带轴倾斜其螺旋轴拍摄的两张高分辨率透射电子显微镜图像，或者通过单个进动电子衍射图案中Bijvoet对反射的强度不对称性来确定旋向性。这两种方法为确定小型手性晶体的旋向性提供了新途径。
