Organobase modulated synthesis of high-quality β-ketoenamine-linked covalent organic frameworks

Abstract

An organobase-assisted approach is adopted to synthesize a series of β-ketoenamine-linked covalent organic frameworks (COFs), exhibiting superior crystallinity and porosity in comparison with those using acidic catalyst. The quality promotion...

Enhanced photocatalytic H2 evolution over covalent organic frameworks through an assembled NiS cocatalyst

“…1b , the PXRD patterns of TpBD-COF, NiS, and NiS X -BD display the prominent X-ray diffraction peaks at 3.30°, 5.85°, and 26.30°, all of which are well assigned to the (100), (200), and (001) planes derived from the typical 2D TpBD-COF. 41 In addition, the X-ray diffraction signals of NiS could not be found due to the relatively low weight percentages in the composite. In the solid-state 13 C CP/MAS NMR spectra (Fig.…”

“…The TpBD-COF was solvothermally prepared according to the previous method. 41 Then, the obtained solid was mixed with the solution containing different concentrations of NiAc 2 and Na 2 S. After stirring at room temperature, NiS could be formed on the surface of TpBD-COF. The synthetic process of the samples is shown in Fig.…”

Yolk–Shell-Structured Covalent Organic Frameworks with Encapsulated Metal–Organic Frameworks for Synergistic Catalysis

“…Besides, pyrrolidine can react to some extent with the residual aldehyde groups in the shell to form an iminium ion, 53 contributing to the attack of the amino groups on the highly electrophilic iminium carbons and thus leading to the efficient reformation of the polyimine networks into COFs. 54 Based on the analyses of experimental results and previous mechanistic studies of COF growth, the formation of the YS-COF@MOF possibly results from the amorphous-to-crystal-line transformation and the simultaneous shrinkage of the shell under the base-catalyzed conditions. The shrinkage of the shell may originate from the disorder-to-order transition of the shell and/or inside-out Ostwald ripening process.…”

“…However, pyrrolidine could replace the adsorbed amino compounds on the MOF surface. Besides, pyrrolidine can react to some extent with the residual aldehyde groups in the shell to form an iminium ion, contributing to the attack of the amino groups on the highly electrophilic iminium carbons and thus leading to the efficient reformation of the polyimine networks into COFs …”

Metal-free Fenton-like photocatalysts based on covalent organic frameworks

“…Tp-Mela COF and Tp-Tapt COF were synthesized according to the literature methods 43,46 with several revamps including the type of solvents, the concentration of the catalyst, and post-treatment methods for optimization, while the previously unreported Tp-Tab COF was prepared with similar solvothermal approaches (see Supporting Information (SI) for details). SEM images show the nanosheets of Tp-Mela COF assemble into a flower-like morphology, forming a hierarchically porous structure and providing abundantly accessible channels for organic pollutants (Figure S1a-b).…”