3D Porphyrin-Based\nCovalent Organic Frameworks

Abstract

The design and synthesis\nof three-dimensional covalent organic\nframeworks (3D COFs) bearing photoelectric units have been considered\nas a big challenge. Herein, for the first time, we reported the targeted\nsynthesis of two 3D porphyrin-based COFs (3D-Por-COF and 3D-CuPor-COF),\nstarting from tetrahedral (3D-<i>T</i>_d) and\nsquare (2D-<i>C</i>₄) building blocks connected\nthrough [4 + 4] imine condensation reactions. On the basis of structural\ncharacterizations, 3D-Por-COF and 3D-CuPor-COF are microporous materials\nwith high surface areas, and are proposed to adopt a 2-fold interpenetrated <b>pts</b> topology with <i>Pmc</i>2₁ space\ngroup. Interestingly, both 3D COFs are photosensitive and can be used\nas heterogeneous catalyst for generating singlet oxygen under photoirradiation.\nHowever, 3D-Por-COF shows enhanced photocatalytic activity compared\nwith 3D-CuPor-COF, indicating the properties of 3D porphyrin-based\nCOFs can be tuned by metalation of porphyrin rings. The results reported\nhere will greatly inspire us to design and synthesize 3D COFs bearing\nother metalloporphyrins for interesting applications (e.g., catalysis)\nin the future.