Chemically Stable Multilayered Covalent Organic Nanosheets from Covalent Organic Frameworks via Mechanical Delamination

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• 作者：Suman Chandra ; Sharath Kandambeth ; Bishnu P. Biswal ; Binit Lukose ; Shrikant M. Kunjir ; Minakshi Chaudhary ; Ravichandar Babarao ; Thomas Heine ; Rahul Banerjee
• 刊名：Journal of the American Chemical Society
• 出版年：2013
• 出版时间：November 27, 2013
• 年：2013
• 卷：135
• 期：47
• 页码：17853-17861
• 全文大小：807K
• 年卷期：v.135,no.47(November 27, 2013)
• ISSN：1520-5126

文摘

A series of five thermally and chemically stable functionalized covalent organic frameworks (COFs), namely, TpPa-NO₂, TpPa-F₄, TpBD-(NO₂)₂, TpBD-Me₂, and TpBD-(OMe)₂ were synthesized by employing the solvothermal aldehyde-amine Schiff base condensation reaction. In order to complete the series, previously reported TpPa-1, TpPa-2, and TpBD have also been synthesized, and altogether, eight COFs were fully characterized through powder X-ray diffraction (PXRD), Fourier transform IR (FT-IR) spectroscopy, ¹³C solid-state NMR spectroscopy, and thermogravimetric analysis. These COFs are crystalline, permanently porous, and stable in boiling water, acid (9 N HCl), and base (3 N NaOH). The synthesized COFs (all eight) were successfully delaminated using a simple, safe, and environmentally friendly mechanical grinding route to transform into covalent organic nanosheets (CONs) and were well characterized via transmission electron microscopy and atomic force microscopy. Further PXRD and FT-IR analyses confirm that these CONs retain their structural integrity throughout the delamination process and also remain stable in aqueous, acidic, and basic media like the parent COFs. These exfoliated CONs have graphene-like layered morphology (delaminated layers), unlike the COFs from which they were synthesized.