Design and synthesis of stable sp2-carbon-linked two-dimensional conjugated covalent organic framework for efficient capture of iodine

• Published in: Separation and purification technology Vol. 307
• Main Authors: Xu, Yulong, Wu, Chengxin, Chu, Ning, Xing, Yanzhi, Yang, Jiaxuan, Yin, Lilin, Chen, Xuwei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-02-2023
• Subjects: Capture; Covalent organic framework; Iodine; Covalent organic framework; Capture; Iodine
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2022.122776

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•Two sp2-c-linked conjugated ingenious 2D COF are prepared via Knoevenagel reaction.•These two COFs exhibit favorable capture capacity towards different I2 statements.•The capture mechanism of two sp2-c-COF towards I2 is explored via DFT calculation.
The ingenious design of sp2-carbon-linked fully π-conjugated covalent organic frameworks (sp2-c-COFs) with a periodic pore structure and high chemical stability, is vital. However, this remains a significant challenge owing to the poor reversibility of the coupling reactions. Here two novel isoreticular crystalline and highly porous two-dimensional (2D) sp2-c-COFs (COF-p-NEU1 and COF-p-NEU2) are designed and synthesized via a base-catalyzed Knoevenagel polycondensation reaction based on the [C2 + C3] topology diagram. As-prepared polycrystalline COF-p-NEU1 (with 1,3,5-tris(p-formylphenyl)benzene (TFP)) and COF-p-NEU2 (with 1,3,5‐tris‐(4‐formylphenyl) triazine (TFT)) exhibit long-range ordered structures, well-defined nanochannels, and favorable chemical stable, which endow the promising capture performance of COF materials. Meanwhile, the two sp2-c-COF can provide abundant functional units to promote the capture of I2 due to introducing mass nitrogen species into the building block. Therefore, the two nitrogen-rich sp2-c-COFs exhibit a high iodine uptake capacity for iodine vapor and iodine in cyclohexane with 4.58 g g−1 and for 1.31 g g−1 COF-p-NEU1 and 5.87 g g−1 and 1.51 g g−1 for COF-p-NEU2 at 348 K. The results of this study provide a potential path for the design and synthesis of novel sp2-c-COFs materials with high chemical stability and demonstrate the high potential of sp2-c-COF for the capture of radioactive contaminants.