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. 2019 Oct 10;10(1):4609.
doi: 10.1038/s41467-019-12596-6.

Rational design of crystalline two-dimensional frameworks with highly complicated topological structures

Rong-Ran Liang  1 , Shun-Qi Xu  1 , Lei Zhang  2 , Ru-Han A  1 , Pohua Chen  2 , Fu-Zhi Cui  1 , Qiao-Yan Qi  1 , Junliang Sun  3 , Xin Zhao  4
Affiliations

Rational design of crystalline two-dimensional frameworks with highly complicated topological structures

Rong-Ran Liang et al. Nat Commun. .

Abstract

Constructing two-dimensional (2D) polymers with complex tessellation patterns via synthetic chemistry makes a significant contribution not only to the understanding of the emergence of complex hierarchical systems in living organisms, but also to the fabrication of advanced hierarchical materials. However, to achieve such tasks is a great challenge. In this communication we report a facile and general approach to tessellate 2D covalent organic frameworks (COFs) by three or four geometric shapes/sizes, which affords 2D COFs bearing three or four different kinds of pores and increases structural complexity in tessellations of 2D polymers to a much higher level. The complex tessellation patterns of the COFs are elucidated by powder X-ray diffraction studies, theoretical simulations and high-resolution TEM.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Design strategy. Cartoon representation of the fabrication of triple-pore and tetrad-pore COFs
Fig. 2
Fig. 2
PXRD profiles of Tri-COF-DAB. a Experimental (black) and Pawley refined (red) PXRD patterns and difference plot (gray) between them, b simulated PXRD patterns with AA stacking, and c AB stacking
Fig. 3
Fig. 3
PXRD profiles of Tetra-COF-DAB. a Experimental (black) and Pawley refined (red) PXRD patterns and difference plot (gray) between them, b simulated PXRD patterns with AA stacking, and c AB stacking
Fig. 4
Fig. 4
PXRD profiles of Tri-COF-BZ. a Experimental (black) and Pawley refined (red) PXRD patterns and difference plot (gray) between them, b simulated PXRD patterns with AA stacking, and c AB stacking
Fig. 5
Fig. 5
PXRD profiles of Tetra-COF-BZ. a Experimental (black) and Pawley refined (red) PXRD patterns and difference plot (gray) between them, b simulated PXRD patterns with AA stacking, and c AB stacking
Fig. 6
Fig. 6
TEM analysis. TEM images of a Tri-COF-DAB, b Tetra-COF-DAB, c Tri-COF-BZ, and d Tetra-COF-BZ. The insets in the upper right corners are magnified images from their corresponding red squares
Fig. 7
Fig. 7
TEM analysis. TEM images of a Tri-COF-DAB and b Tetra-COF-DAB, and HR-TEM images of c Tri-COF-DAB and d Tetra-COF-DAB focusing on the regions marked by the red squares in a and b at a higher resolution. The images inserted in the upper right corners are their corresponding FFT patterns, and the structure projections in HR-TEM images are along the b-axis and the structural models are inserted in the middle
Fig. 8
Fig. 8
TEM analysis. TEM images of a Tri-COF-BZ and b Tetra-COF-BZ, and HR-TEM images of c Tri-COF-BZ and d Tetra-COF-BZ focusing on the regions marked by the red squares in a and b at a higher resolution. The images inserted in the upper right corners are their corresponding FFT patterns, the structure projections in HR-TEM images are along the b-axis and the structural models are inserted in the middle
Fig. 9
Fig. 9
Porosity measurements. N2 adsorption−desorption isotherms (77 K) of a Tri-COF-DAB, b Tetra-COF-DAB, c Tri-COF-BZ, and d Tetra-COF-BZ
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