A quinoline-linked and ionic liquid-decorated covalent organic framework was prepared by incorporation of a multicomponent Povarov reaction and postsynthetic modification. The imidazolium and ...sulfonic acid-decorated COF-IM-SO3H can be a highly efficient Brønsted acid catalyst to promote the Biginelli reaction under solvent-free conditions in a heterogeneous way. In addition, a scaled-up Biginelli reaction has been readily realized over a COF-IM-SO3H@chitosan aerogel-based cup reactor.
Postsynthetic modification (PSM) has been demonstrated to be a powerful method for achieving new covalent organic frameworks (COFs) via single-step or multistep organic functional group ...transformations on established COF frameworks. PSM, however, might sometimes lead to collapse of the COF framework, decreases in crystallinity, or low postsynthetic yield due to the inherent limit of solid-state synthesis. Herein we report, for the first time, a new synthetic strategy that can generate new COFs via multicomponent one-pot in situ reactions. In total, 12 α-aminonitrile- and quinoline-linked COFs with high crystallinity and permanent porosity are successfully achieved by three-component one-pot in situ Strecker and Povarov reactions under solvothermal conditions in high yields. The obtained COFs feature the same structures as those obtained from the stepwise PSM approach on an established imine-linked COF. This in situ multicomponent assembly strategy, as a synthetic methodology parallel to PSM, might open a new route for constructing COFs that is not possible under PSM conditions.
(S)-2-(2-Chlorophenyl)-2-(6,7-dihydrothieno3,2-cpyridin-5(4H)-yl)acetonitrile ((S)-CIK) is a key intermediate in the synthesis of (S)-clopidogrel, which is one of the most saleable worldwide ...antiplatelet and antithrombotic drugs. We show herein a facile method for the direct synthesis of (S)-CIK via Strecker reaction using a homochiral covalent framework catalyst in a heterogeneous way. The asymmetric synthesis involves a photothermal-conversion-triggered, thermally driven reaction which affords (S)-CIK in 98% yield with 94% enantiomeric excess under visible-light irradiation. Furthermore, the above approach is readily extended to a gram-scale level on a fixed-bed continuous-flow model reactor. The potential utility of this strategy is highlighted by the preparation of many more other types of chiral drugs and drug intermediates in a green and facile way.
Owing to their permanent porosity, highly ordered and extended structure, good chemical stability, and tunability, covalent organic frameworks (COFs) have emerged as a new type of organic materials ...that can offer various applications in different fields. Benefiting from the huge database of organic reactions, the required functionality of COFs can be readily achieved by modification of the corresponding organic functional groups on either polymerizable monomers or established COF frameworks. This striking feature allows homochiral covalent organic frameworks (HCCOFs) to be reasonably designed and synthesized, as well as their use as a unique platform to fabricate asymmetric catalysts. This contribution provides an overview of new progress in HCCOF‐based asymmetric catalysis, including design, synthesis, and their application in asymmetric organic synthesis. Moreover, major challenges and developing trends in this field are also discussed. It is anticipated that this review article will provide some new insights into HCCOFs for heterogeneous asymmetric catalysis and help to encourage further contributions in this young but promising field.
Chirality from COFs: Owing to their permanent porosity, highly ordered and extended structure, good chemical stability, and tunability, covalent organic frameworks have emerged as a new type of organic materials that can offer various applications in different fields. Herein, the design and synthesis of chiral covalent organic frameworks and their applications in asymmetric catalysis are highlighted.
Chronic wound infections resulting from severe bacterial invasion have become a major medical threat worldwide. Herein, we report a large-area, homogeneous, and self-standing porphyrin-covalent ...organic framework (COF)-based membrane with encapsulated ibuprofen (IBU) via an in situ interfacial polymerization and impregnation approach. The obtained IBU@DhaTph-membrane exhibits highly effective antibacterial and anti-inflammatory effects via synergistic light-induced singlet oxygen (
O
) generation and controllable IBU release, which is well supported by in vitro experiments. In addition, the IBU@DhaTph-membrane-based biocompatible "band-aid" type dressing is fabricated, and its excellent anti-infection and tissue remodeling activities are fully evidenced by in vivo chronic wound-healing experiments. This study may inspire and promote the fabrication of many more new types of COF-based multifunctional biomaterials for various skin injuries in clinical medicine.
Metal–organic frameworks (MOFs) are widely used as porous materials in the fields of adsorption and separation. However, their practical application is largely hindered by limitations to their ...processability. Herein, new UiO‐66‐Urea‐based flexible membranes with MOF loadings of 50 (1), 60 (2), and 70 wt % (3) were designed and prepared by post‐synthetic polymerization of UiO‐66‐NH2 nanoparticles and a polyurethane oligomer under mild conditions. The adsorption behavior of membrane 3 towards four hydrophilic dyes, namely, eosin Y (EY), rhodamine B (RB), malachite green (MG), and methylene blue (MB), in aqueous solution was studied in detail. It exhibits strong adsorption of EY and RB but weak adsorption of MG and MB in aqueous solution. Owing to the selective adsorption of these hydrophilic dyes, membrane 3 can remove EY and RB from aqueous solution and completely separate EY/MB, RB/MG, and RB/MB mixtures in aqueous solution. In addition, the membrane is uniformly textured, easily handled, and can be reused for dye adsorption and separation.
Mixed‐matrix membranes: UiO‐66‐Urea‐based flexible membranes were prepared by post‐synthetic polymerization of UiO‐66‐NH2 metal–organic framework nanoparticles and a polyurethane oligomer, and their adsorption behavior towards the hydrophilic dyes eosin Y (EY), rhodamine B (RB), malachite green (MG), and methylene blue (MB) was studied in aqueous solution. They exhibits strong adsorption of EY and RB but weak adsorption of MG and MB, and can remove EY and RB from aqueous solution and completely separate EY/MB, RB/MG, and RB/MB mixtures (see figure).
Herin, we report a Cu(ii)-porphyrin-derived nanoscale COF, which can be triggered by endogenous H2S via an intracellular sulfidation reaction to generate a metal-free COF-photosensitizer for PDT ...against H2S-enriched colon tumors with controllable singlet oxygen release; meanwhile in situ generated CuS can be synchronously used as a photothermal agent for PTT.
Homochiral metal–organic frameworks with fine-tuned pore sizes/walls and large surface areas are promising porous materials for enantioseparation considering the traditional zeolite molecular sieves ...have no chirality. Using enantiopure pyridyl-functionalized salen (N-(4-Pyridylmethyl)-l-leucine·HBr) as a starting material, we have prepared a noninterpenetrated three-dimensional homochiral metal organic framework {ZnLBr·H2O} n , which was further used as a chiral stationary phase for high-performance liquid chromatography to enantioseparate racemic drugs, showing excellent performances in enantioseparation of drugs. The metal–organic framework can be regarded as a novel molecular sieve-like material with a chiral separation function based on the relative sizes of the chiral channels and the resolved molecules.
A Pd NP-loaded and paraffin-chain quaternary ammonium salt-decorated covalent organic framework, Pd@COF-QA , and its chitosan aerogel-based continuous flow-through reactor, which could be an ...excellent phase transfer catalyst to promote the aqueous Suzuki–Miyaura coupling reaction, is reported.
Herein, we report an inorganic photothermal agent, CuS- and an organic photosensitizer, BODIPY-loaded composite nanoscale COF material
via
a stepwise post-synthetic modification. The obtained ...CuS@COF-BDP can be a dual-modal therapeutic agent to highly inhibit MCF-7 tumor cell proliferation due to its efficient singlet oxygen generation and photothermal conversion abilities.
A COF-based multifunctional nanomedicine CuS@COF-BDP, which can be used as a PTT/PDT bimodal therapeutic agent to inhibit cancer cell proliferation under visible- and NIR-II-light irradiation, is reported.
