A covalent organic framework–MnO2 nanosheet system for determination of glutathione

Title: Cr(III) Incorporated Melamine‐Terephthalaldehyde Porous Organic Framework Nanosheet Catalyst for Carbon Dioxide Fixation Reaction

“…Moreover, the prominent peak of aromatic dialdehydes at 2859 cm −1 (C−H stretching) and 1689 cm −1 (C=O stretching) (Figure S2, ESI) were also absent in the synthesized POF. IR spectrum of the MT‐POF shows peaks at 1560 and 1482 cm −1 due to C=N vibrations of melamine triazine ring confirming the incorporation of melamine moiety into the framework [85] . Presence of peaks at 1344, 1190 and 815 cm −1 also supports the successful formation of MT‐POF.…”

“…Further, the peak at 399 eV of N1s can be deconvoluted to two peaks at 398.3 and 399.4 eV corresponding to the C=N of the triazine ring and NÀ H of amine groups, respectively (Figure 5c). [85] XPS full spectrum of MT-Cr(III) POF (Figure 6a) shows peaks at 285, 400, 532, 577 and 587 eV corresponding to C1s, N1s, O1s and Cr2p, respectively. As in MT-POF, the peak at 285 eV for C1s can be fitted into four peaks 284.7, 285.7, 289.0 and 289.7 eV (Figure 6b) and the peak at 400 eV for N1s can be fitted into two peaks 398.9 and 400.6 eV (Figure 6c).…”

“…Moreover, very few reports [64–67] are there, where metal‐free melamine/triazine based POFs are used as catalysts in CO 2 cycloaddition to epoxides to yield cyclic carbonates, though there are numerous reports of various applications of melamine based COF [78–85] …”

“…Moreover, very few reports [64][65][66][67] are there, where metal-free melamine/triazine based POFs are used as catalysts in CO 2 cycloaddition to epoxides to yield cyclic carbonates, though there are numerous reports of various applications of melamine based COF. [78][79][80][81][82][83][84][85] Herein, we have reported metalation of the previously reported melamine-terephthalaldehyde POF [81] with Cr(III), its subsequent mechanical exfoliation to nanosheets, and application as catalyst for the chemical fixation of CO 2 with epoxides to yield cyclic carbonate products.…”

Covalent-Organic-Framework-Based Composite Materials

“…Based on the synergistic effect between COFs and MnO 2 nanosheets, Han et al developed a sensitive chemosensor for glutathione detection. 54 The MnO 2 nanosheets in the composite serve as an effective quencher for the fluorescence of COFs. On account of the reducing property of glutathione, MnO 2 can be reduced to Mn 2+ and the quenched fluorescence of COFs would be easily recovered.…”