02243nas a2200241   4500008004100000022001400041245012400055210006900179260007100248300001600319490000800335520133000343100001901673700002401692700002301716700001801739700002501757700002801782700002501810700001801835700002001853856012801873       2013                        eng d  a0002-786300aChemically stable multilayered covalent organic nanosheets from covalent organic frameworks via mechanical delamination0 aChemically stable multilayered covalent organic nanosheets from   a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcNOV  a17853-178610 v1353 a<p>A series of five thermally and chemically stable functionalized covalent organic frameworks (COFs), namely, TpPa-NO2, TpPa-F-4, TpBD-(NO2)(2), TpBD-Me-2, 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, C-13 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.</p>1 aChandra, Suman1 aKandambeth, Sharath1 aBiswal, Bishnu, P.1 aLukose, Binit1 aKunjir, Shrikant, M.1 aChaudhary, Minakshi, V.1 aBabaRao, Ravichandar1 aHeine, Thomas1 aBanerjee, Rahul  uhttps://library.ncl.res.in/content/chemically-stable-multilayered-covalent-organic-nanosheets-covalent-organic-frameworks-0