Ren, S.; Sun, S.; Xu, M.; Li, S.; Ding, Y.; Shao, M. Lattice Shrinkage of 2D-COFs under Electron Beam Irradiation. Processes2023, 11, 2859.
Ren, S.; Sun, S.; Xu, M.; Li, S.; Ding, Y.; Shao, M. Lattice Shrinkage of 2D-COFs under Electron Beam Irradiation. Processes 2023, 11, 2859.
Ren, S.; Sun, S.; Xu, M.; Li, S.; Ding, Y.; Shao, M. Lattice Shrinkage of 2D-COFs under Electron Beam Irradiation. Processes2023, 11, 2859.
Ren, S.; Sun, S.; Xu, M.; Li, S.; Ding, Y.; Shao, M. Lattice Shrinkage of 2D-COFs under Electron Beam Irradiation. Processes 2023, 11, 2859.
Abstract
Over the past two decades, covalent organic frameworks (COFs) have become the most widely studied porous crystalline materials. Its specific physical and chemical properties are determined by the arrangement of atoms (crystal structure). Therefore, the determination of its structure is arguably the most important characterization step for COFs. Although single crystal X-ray diffraction (SCXRD) is the most widely used method for structure determination, the size of COF crystals is too small, or their crystal quality is so poor that confirmation of their structure is limited to lattice fringes by transmission electron microscopy (TEM). At present, many 2D-COFs have clear PXRD patterns, but not all 2D-COFs can obtain specific lattice fringes. This severely hinders the development of the COF field. Here, we discover the lattice shrinkage behavior of COFs under electron beam irradiation by comparing the lattice fringes of 2D-COFs under different conditions. By comparing the lattice fringes of TAPT-TFPT COF at room temperature and under liquid nitrogen freezing conditions, we found that the lattice fringes are in good agreement with the Powder X-ray diffraction (PXRD) and theoretical values of COF (2.213 nm) under freezing conditions, however, the lattice fringe spacing is only 1.656 nm at room temperature. The discovery not only provides new insights into the TEM characterization of COFs, but also further expands the range of crystalline COF materials.
Keywords
lattice shrinkage, two-dimensional covalent organic frameworks, electron beam irradiation, transmission electron microscopy.
Subject
Chemistry and Materials Science, Materials Science and Technology
Copyright:
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