A general and efficient organocatalytic asymmetric polymerization approach for the synthesis of chiral covalent organic frameworks (CCOFs) has been developed. With a chiral 2‐methylpyrrolidine ...catalyst, a series of tris(N‐salicylideneamine)‐derived β‐ketoenamine‐CCOFs are directly constructed from prochiral aldehyde‐ and primary amine‐monomers. The adopted aminocatalytic asymmetric Schiff‐base condensation herein is performed under ambient conditions with clear green synthetic advantages over the conventional acid‐catalysed solvothermal methods. The obtained β‐ketoenamine‐CCOFs can be further metalated by a solid‐state coordination approach, and the resulting CuII@CCOFs can highly promote an asymmetric A3‐coupling reaction. Specifically, a CuII@CCOF@chitosan aerogel was fabricated as a highly efficient fixed‐bed model reactor for scaled‐up catalysis. The concept of aminocatalytic asymmetric polymerization might open a new way for constructing the CCOFs via asymmetric organocatalysis.
A new and general organocatalytic asymmetric polymerization approach for the chiral covalent organic framework (CCOF) synthesis under ambient conditions is presented. The metalated CCOF can be further shaped into a fixed‐bed reactor by incorporation with ecofriendly and low‐cost chitosan to realize the scaled‐up catalytic asymmetric A3‐coupling reaction in a green and facile way.
Photothermal therapy in the second near-infrared window (NIR-II, 1000-1700 nm) exhibits a significant advantage over the first near-infrared window (NIR-I, 650-950 nm) in terms of both maximum ...permissible exposure (MPE) and penetration depth. However, the thus far reported NIR-II photothermal agents (PTAs) have been focused just on inorganic semiconducting and organic polymeric semiconducting nanoparticles. Herein a novel cruciform phthalocyanine pentad was designed, synthesized, and characterized for the first time. The water-soluble nanoparticles (Zn
4
-H
2
Pc/DP NPs) assembled from this single molecular material with the help of DSPE-PEG
2000
-OCH
3
exhibit characteristic absorption in the NIR-II region at 1064 nm with a large extinction coefficient of 52 L g
−1
cm
−1
, high photothermal conversion efficiency of 58.3%, and intense photoacoustic signal. Moreover, both
in vitro
and
in vivo
studies reveal the good biocompatibility and notable tumor ablation ability of Zn
4
-H
2
Pc/DP NPs under 1064 nm laser irradiation. Theoretical density functional theory calculations interpret the two-dimensional compressional wave energy-dissipation pathway over the broad saddle curved framework of the cruciform conjugated phthalocyanine pentad, rationalizing the efficient photothermal properties of corresponding Zn
4
-H
2
Pc/DP NPs in the NIR-II window.
The first molecular material-based PTA for the NIR-II photothermal therapy with high PCE of 58.3% was reported. The Zn
4
-H
2
Pc/DP NPs reveal good biocompatibility and notable tumor ablation ability in 1064 nm.
Covalent organic frameworks (COFs) have recently drawn intense attention due to their potential applications in photocatalysis. Herein, we report a multifunctional COF which consists of ...triphenylamine (TPA) and 2,2′‐bipyridine (2, 2′‐bipy) entities. The obtained TAPA−BPy−COF is a heterogeneous photocatalyst and can efficiently catalyze the oxidative coupling of thiols to disulfides. In addition, TAPA−BPy−COF can be further metalated by Pd(II) via 2,2′‐bipy−metal coordination. The generated Pd@TAPA−BPy−COF can highly promote photocatalytic synthesis of 3‐cyanopyridines via cascade addition/cyclization of arylboronic acids with γ‐ketodinitriles in heterogeneous way. This work has demonstrated the way for the rational design and preparation of more efficient photoactive COFs for photocatalysis.
A photoactive TAPA−BPy−COF and its metalated Pd@TAPA−BPy−COF, which can both serve as the efficient reusable photocatalysts for photocatalytic applications, are reported.
Stimulus-responsive biodegradable nanocarriers with tumor-selective targeted drug delivery are critical for cancer therapy. Herein, we report for the first time a redox-responsive disulfide-linked ...porphyrin covalent organic framework (COF) that can be nanocrystallized by glutathione (GSH)-triggered biodegradation. After loading 5-fluorouracil (5-Fu), the generated nanoscale COF-based multifunctional nanoagent can be further effectively dissociated by endogenous GSH in tumor cells, releasing 5-Fu efficiently to achieve selective chemotherapy on tumor cells. Together with the GSH depletion-enhanced photodynamic therapy (PDT), an ideal synergistic tumor therapy for MCF-7 breast cancer
via
ferroptosis is achieved. In this research, the therapeutic efficacy was significantly improved in terms of enhanced combined anti-tumor efficiency and reduced side effects by responding to significant abnormalities such as high concentrations of GSH in the tumor microenvironment (TME).
Stimulus-responsive biodegradable nanocarriers with tumor-selective targeted drug delivery are critical for cancer therapy.
Metal-free radiosensitizers, particularly iodine, have shown promise in enhancing radiotherapy due to their suitable X-ray absorption capacities and negligible biotoxicities. However, conventional ...iodine compounds have very short circulating half-lives and are not retained in tumors very well, which significantly limits their applications. Covalent organic frameworks (COFs) are highly biocompatible crystalline organic porous materials that are flourishing in nanomedicine but have not been developed for radiosensitization applications. Herein, we report the room-temperature synthesis of an iodide-containing cationic COF by the three-component one-pot reaction. The obtained
TDI-COF
can be a tumor radiosensitizer for enhanced radiotherapy by radiation-induced DNA double-strand breakage and lipid peroxidation and inhibits colorectal tumor growth by inducing ferroptosis. Our results highlight the excellent potential of metal-free COFs as radiotherapy sensitizers.
An iodide-containing cationic covalent organic framework as a nonmetallic radiosensitizer increases X-ray deposition and enhances radiotherapy of colon cancer
in vitro
and
in vivo
by inducing ferroptosis.
Herein, we report the first reactive oxygen species (ROS)-responsive dithioketal-linked covalent organic framework (COF) for synergetic chemotherapy and photodynamic therapy (PDT) of cancer. The ...singlet oxygen (
O
)-responsive COF dissociation and DC_AC50 drug release complement and reinforce each other to allow an efficient combination of PDT and chemotherapy.
Comprehensive Summary
Covalent organic frameworks (COFs) driven photocatalytic organic transformations especially photooxidation reactions have become a fertile topic and attracted numerous research ...attentions. Boosting the charge generation and transport process is the key factor for achieving high catalytic efficiencies. As one of the most effective strategies, the introduction of “heavy atoms” into the long‐range ordered conjugated backbones can effectively facilitate the intersystem crossing (ISC) process and hence improve the generation of active oxygens, which is beneficial for the oxidation. In this work, we designed and synthesized a benzoselenadiazole based covalent organic framework (COF) material, BSe‐COF with heavy atom of selenium (Se), and a benzothiadiazole based BT‐COF with isomorphic backbone for comparison. Compared to BT‐COF, BSe‐COF exhibits broader absorption range, stronger photocurrent response and enhanced intersystem crossing (ISC) with higher singlet oxygen (1O2) generation efficiency. When applied in photocatalytic organic transformation, BSe‐COF presents remarkably higher photocatalytic activity in the oxidation of sulfides than BT‐COF under the irradiation of blue LED lamp. Furthermore, BSe‐COF can be used as efficient photocatalyst for the window ledge reaction with high yields (over 84%) of various sulfoxides from a wide range of thioether substrates scope.
A covalent organic framework (COF) with heavy‐atom selenium (Se) was synthesized and applied into the window ledge photocatalytic oxidation of sulfides to sulfoxides.
2‐Aminobenzothiazoles are widely used in the fields of pharmaceuticals and pesticides. Herein, we report a metal‐free protocol for the preparation of 2‐aminobenzothiazoles by a covalent organic ...framework (COF) catalyzed tandem reaction. In the presence of catalytic amount of phenanthroline‐decorated COF (Phen‐COF), a variety of 2‐aminobenzothiazoles are obtained in excellent yields by the cross‐coupling of 2‐iodoanilines with isothiocyanates at room temperature in water. In addition, the COF‐catalyst is very stable and can be reused at least seven times without loss of its catalytic activity.
A phenanthroline‐decorated covalent organic framework, which can highly promote room‐temperature synthesis of 2‐aminobenzothiazoles by cross‐coupling of 2‐iodoanilines with isothiocyanates in water, is reported.
By using a catalytic amount of a porphyrin‐based covalent organic framework (Por‐Ad‐COF) as the efficient recyclable photocatalyst, the photocatalytic oxidative 3+2 cycloaddition reaction between ...tetrahydroisoquinolines and N‐substituted maleimides was developed under aerobic conditions at room temperature. Various substituted pyrrolo2,1‐aisoquinolines were obtained in moderate to good yields via the dipolar 3+2 cycloaddition and oxidative aromatization cascade process under visible light irradiation. This was the first example to employ the covalent organic framework as the heterogeneous photocatalyst to perform the photocatalytic dipolar 3+2 cycloaddition reaction for the synthesis of pyrrolo2,1‐aisoquinolines.
A porphyrin‐based COF promoted photocatalytic dipolar 3+2 cycloaddition reaction for pyrrolo2,1‐aisoquinoline synthesis is reported. Various substituted pyrrolo2,1‐aisoquinolines were obtained in moderate to good yields via the photocatalytic oxidative 3+2 cycloaddition reaction between tetrahydroisoquinolines and N‐substituted maleimides under aerobic conditions at room temperature.
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