Three-Dimensional Covalent Organic Framework with ceq Topology

Abstract

Three-dimensional covalent organic frameworks (3D-COFs) are emerging as designable porous materials because of their unique structural characteristics and porous features. However, because of the lack of 3D organic building units and the less reversible covalent bonds, the topologies of 3D-COFs to date have been limited to dia, ctn, ffc, bor, rra, srs, pts, lon, stp, acs, tbo, bcu, and fjh. Here we report a 3D-COF with the ceq topology utilizing a D 3h -symmetric triangular prism vertex with a planar triangular linker. The as-synthesized COF displays a twofold-interpenetrated structure with a Brunauer–Emmett–Teller surface area of 1148.6 m2 g–1. Gas sorption measurements revealed that 3D-ceq-COF could efficiently absorb CO2, CH4, and H2 under a moderate surface area. This work provides new building units and approaches for structural and application exploration of 3D-COFs.

Three‐Dimensional Crystalline Covalent Triazine Frameworks via a Polycondensation Approach

“…The disappearance of the characteristic vibration at 1702 cm À 1 (À C=O stretching vibration) confirms that the polycondensation reaction is completed (Figures S1 and S2). From the CP-MAS 13 C NMR spectra, the carbon signal peaks at 170.8 ppm for 3D CTF-TPM and at 170.4 ppm for 3D CTF-TPA (Figure 1b) confirm the formation of triazine structures in the 3D CTFs, and the disappearance of the carbon signal peak for aldehyde ( � 192 ppm) confirms the completion of the polycondensation reaction, which is consistent with the FT-IR spectra. The elemental analysis (EA) results show the carbon contents and nitrogen contents of CTF-TPM and CTF-TPA are close to the theoretical values (Table S1).…”

“…The successful formation of the 3D CTFs was confirmed by Fourier-transformed infrared (FT-IR) analysis and the solid-state 13 C cross-polarization magic angle spinning (CP/ MAS NMR) spectra. From the FT-IR spectra, the characteristic vibrations at 1511 cm À 1 (À C=NÀ stretching vibration) and 1362 cm À 1 (À CÀ N= stretching vibration) indicate the successful formation of the triazine rings (Figure 1a).…”

Reticular design and crystal structure determination of covalent organic frameworks

“…Particularly, Cooper and coworkers reported the synthesis of the acs topology COF based on triangle prism (6-c) and linear (2-c) building units. 46 Later, this 6-c SBU was linked by 3-c and 4-c to form ceq 47 and stp 48 topologies, respectively.…”

Prediction on the high‐energy density covalent organic frameworks with diamond network

“…Three‐dimensional covalent organic frameworks (COFs) are a new class of materials created by linking organic building blocks through CB, BO, CC, and CSi bonds into various interpenetrated nets based on the principles of reticular chemistry [17–25]. For example, the condensation of tetra‐(4‐anilyl)methane with the linear linker terephthaldehyde results in a diamond structure COF‐300 connected by the rod‐like bis‐imine (>C═N) bonds [26].…”