A Facile, Efficient, and General Synthetic Method to Amide-Linked Covalent Organic Frameworks

Abstract

Amide-linked covalent organic frameworks (amide COFs) possess enormous potentials in practical applications benefiting from their high stability and polyamide structures. However, they suffer from very limited accessibility. Herein, we report a new linkage conversion method to rapidly synthesize crystalline amide COFs through oxidation of imine linkages in their corresponding imine-linked frameworks with KHSO 5 as an oxidant under very mild conditions. This synthetic strategy is general, facile, efficient, and scalable, as demonstrated by the procedure of simply stirring mixtures of imine-linked COFs (seven examples) and KHSO 5 in anhydrous dimethylformamide for several hours to complete the conversions and gram-scale synthesis. The high efficiency of this approach enables facile production of amide COFs from widely available imine-linked COFs, which lays the foundation for exploring practical applications of this unique type of polyamide material.

Construction of Ultrastable Nonsubstituted Quinoline‐Bridged Covalent Organic Frameworks via Rhodium‐Catalyzed Dehydrogenative Annulation

“…[24] Imine-linked COFs are the most widely studied subclass of COFs, and various PSM and OPR approaches have been designed to convert the C=N linkage into chemically robust moieties. [25][26][27][28][29][30][31][32][33] For example, Baek, [34] Babu, [35] Lotsch [36] and Liu [37] et al have developed innovative chemistry to transform the imine bonds to cyclic fragments such as benzoxazole, benzimidazole, benzothiazole and quinoline. Formation of these linkages also helps to enhance the in-plane π electron delocalization, thus increasing the visible light absorption and promoting the separation of the carriers.…”

“…Imine‐linked COFs are the most widely studied subclass of COFs, and various PSM and OPR approaches have been designed to convert the C=N linkage into chemically robust moieties [25–33] . For example, Baek, [34] Babu, [35] Lotsch [36] and Liu [37] et al.…”

Ambient synthesis of an iminium-linked covalent organic framework for synergetic RNA interference and metabolic therapy of fibrosarcoma

“…S1E † ). 58 XPS analysis of ABMI-COF in the N1s region was deconvoluted into a C N + peak at 401.1 eV and a C N peak at 398.3 eV (Fig. S1F † ).…”

Selective Detection of Nucleotides in Infant Formula Using an N-Rich Covalent Triazine Porous Polymer

“…To address this problem, pre-synthetic methods such as modification of the precursor monomers, or post-synthetic steps, including modification of the organic backbone of the COF, were used to introduce specific chemical functionality into the pores of the polymers, tailoring interactions with specific guests while making full use of the surface area and high porosity of the frameworks [13][14][15][16][17][18]. However, both pre-synthetic and post-synthetic modification of COFs generally necessitated tedious synthetic efforts and often harsh experimental conditions and frequently led to side reactions and interfered with the COF formation, all issues that greatly limited the generality of these approaches [13,15,[19][20][21][22].…”