Latest ArticlesHeterogeneous metal-catalyzed chemical conversions with a recyclable catalyst are very ideal and challenging for sustainable organic synthesis. A new bipyridyl-Mo(Ⅳ)-carbon nitride (CN-K/Mo-Bpy) was prepared by supporting molybdenum complex on C3N4-K and characterized by FT-IR, XRD, SEM, XPS and ICP-OES. Heterogeneous CN–Mo-Bpy catalyst can be applied to the direct amination of nitroarenes and arylboronic acid, thus constructing various valuable diarylamines in high to excellent yields with a wide substrate scope and good functional group tolerance. It is worth noting that this heterogeneous catalyst has high chemical stability and can be recycled for at least five times without reducing its activity.
Supramolecular prodrug vesicles (H-4⊃B-2@MB) with selective antibacterial activity have been successfully constructed. Specifically, a natural antibiotic prodrug (B-2) with glutathione (GSH)-responsiveness was synthesized. The hydrophobic interaction between B-2 and a novel water-soluble cavitand with deep cavity (H-4) resulted in the formation of a host-guest complex, which further self-assembled into supramolecular vesicles. The formed vesicles could effectively encapsulate the photosensitizer methylene blue (MB), enabling co-delivery of antibiotics and photosensitizers in the presence of GSH. Moreover, upon excitation at 630 nm, the photosensitizers generate reactive oxygen species (ROS), effectively eradicating E. coli through combined chemo-photodynamic therapy. Considering that GSH is predominantly present in Gram-negative bacteria such as E. coli, this strategy exhibits substantial potential for selectively inhibiting bacteria characterized by high GSH levels to regulate bacterial colony equilibrium.
A photoredox-catalyzed synthesis of α,α-difluoromethyl sulfones from sulfur dioxide with readily available gem–difluoroalkenes is reported. This protocol features mild reaction conditions, broad substrate scope and good functional group compatibility, giving rise to the target α,α-difluoromethyl sulfones in moderate to excellent yields. Mechanistic studies indicate that this reaction is initiated by an aryl radical with the insertion of sulfur dioxide.
Controllable construction of organic heterostructures is key to developing supramolecular materials with sophisticated functions. Herein, block heterostructures with controllable shape and dimension have been successfully constructed from one molecular pair of Ir(Ⅲ) complexes 1 and 2 in H2O/CH3CN. Different volume ratios of H2O/CH3CN led to controllable morphologies of assemblies 1 from nanofibers (1NF) to nanosheets (1NS). Through reasonable experimental design, both 1NF and 1NS could be used as seeds to trigger the heterogeneous nucleation-elongation of 2. Finally, unprecedented dual control on the length and width of supramolecular block copolymers from the same monomer pair was realized smoothly. The corresponding heterogeneous nucleation-elongation process was confirmed by time-dependent UV–vis absorption spectra and emission spectra. The components of each segment of the fibrous and sheet-like block copolymers were identified by TEM, SEM, and CLSM. The results reveal that the previously unappreciated solvation effect can serve as a powerful tool to control the morphologies of heterostructures.
Microplastics (MPs) are an emerging environmental pollutant and have penetrated the most remote and primitive areas. MPs degradation has received widespread attention. Manganese (Mn) is a highly reactive metal element in the environment, yet its contribution to MPs degradation remains unclear. Herein, we simulated the aging of polyethylene MPs with Mn(Ⅱ) under aqueous conditions at pH 5 and 8 for 720 days. Mn greatly promoted the MPs degradation, and the average particle sizes of polyethylene MPs were reduced from 9.2 µm to 5.9 µm after aging at pH 5 under light irradiation for 720 days. Plenty of oxygen-containing groups were generated on the MPs surfaces, and the carbonyl index remarkably increased, reaching four times that of the control without adding Mn. Mechanistically, the adsorbed Mn(Ⅱ) on the MPs surfaces were primarily oxidized to high-valence Mn(Ⅲ/Ⅳ) profited from the photoproduced radicals, followed by the MPs oxidation via Mn(Ⅲ/Ⅳ), which were reduced to regenerate Mn(Ⅱ), initiating a new redox cycling. During the degradation, dissolved organic matter was continuously released, mainly including bisphenol A and phthalic acid esters. Mn acts as a catalyst to accelerate the MPs degradation by redox cycling. Our results provide a new insight into the mechanisms of abiotic degradation of MPs in aqueous environments.
The complexity of cancer therapy has led to the emergence of combination therapy as a promising approach to enhance treatment efficacy and safety. The integration of glutathione (GSH)-activatable two-photon photodynamic therapy (TP-PDT) and chemodynamic therapy (CDT) offers the possibility to advance precision and efficacy in anti-cancer treatments. In this study, a GSH-activatable photosensitizer (PS), namely copper-elsinochrome (CuEC), is synthesized and utilized for combination second near-infrared (NIR-Ⅱ) TP-PDT/CDT. The Cu2+ acts as a “lock”, suppressing the fluorescence and 1O2 generation ability of EC in a normal physiological environment (“OFF” state). However, the overexpressed GSH in the tumor microenvironment acts as the “key”, resulting in the release of EC (“ON” state) and Cu+ (reduced by GSH). The released EC can be utilized for fluorescence imaging and TP-PDT under NIR-Ⅱ (λ = 1000 nm) two-photon excitation, while Cu+ can generate highly toxic hydroxyl radicals (•OH) via Fenton-like reaction for CDT. Additionally, this process consumes GSH and diminishes the tumor’s antioxidant capacity, thereby augmenting the efficacy of combination therapy. The CuEC achieves significant tumor cell ablation in both 2D monolayer cells and 3D multicellular tumor spheres through the combination of NIR-Ⅱ TP-PDT and CDT.
Mn-rich layered oxides are appealing cathodes for potassium ion batteries (PIBs) in view of their comprehensive virtues such as low cost, high energy density and mature craftsmanship. However, the insufficient covalency between transition metal (TM) and O usually induces irreversible structural evolution and cation migration during repeated insertion and extraction of K+, resulting in capacity loss, voltage fading and sluggish kinetics. Herein, an anion substitution strategy is proposed for a stable operation of layered oxide cathode by adjusting the valence electron layer structure between TM and O. The resultant strong TM−O skeleton can inhibit the occurrence of side effects derive from Ni4+ during the deep depotassium process, so as to achieve a gentle structural transition. Consequently, stable cycling performance of K0.39Mn0.77Ni0.23O1.9F0.1 (KMNOF) cathode is achieved with 77% capacity retention over 350 cycles at 100 mA/g, yielding high discharge capacity 93.5 mAh/g at 20 mA/g and significantly improved rate capability of 50.1 mAh/g at 500 mA/g, whereas irreversible structural evolution and rapid capacity fade with KMNO cathode. Finally, in situ/ex situ characterizations and theoretical computations sheds light on the charge transfer and structure evolution mechanisms of KMNOF.
Rational tuning of chiral nanostructures of supramolecular assemblies as catalysts and investigating their chiral morphology-enantioselectivity dependence is rarely reported. Herein, we report a series of supramolecular M/P-helical nanoribbons (HNs) assembled from the chiral L/D-glutamate-based amphiphiles (L/D-GluC16) and Cu(Ⅱ) ions, with their helical screw pitches adjusted from 217 nm to 104 nm through the facile regulation of their water/organic solvent assembly environment. They were then used as ideal models to reveal the chiral morphology-enantioselectivity relationship by catalyzing the asymmetric Diels-Alder reaction. Better enantioselectivity was achieved with more twist morphology. Experimental evidences of stronger chiral transfer effect from the supramolecular HNs with more twist to the aza-chalcone as reactant were obtained to understand such dependence. Our study demonstrates a new perspective for designing supramolecular catalysts with higher enantioselectivity.
Oral ulcers are a common ulcerative injury that occurs in the oral mucosa. When occurring, they can cause mucosal pain and affect eating and communication. The oral cavity, characterized by its moist environment and constant movement of the lips and tongue, presents challenges for conventional drug delivery systems due to its suboptimal adhesion. Therefore, there is a need for the development of adhesive materials specifically designed for use within the oral cavity. In this research, a sticky coacervate incorporating tea polyphenols (TP) was formulated based on the adhesive properties observed in sandcastle worms. The coacervate is composed of Pluronic F68 (F68) and TP, synthesized through the coacervation reaction. The F68-TP coacervates are attached to porcine skin easily. It also reduces bacterial viability and has the ability to clear reactive oxygen species. In animal ulcer models, these coacervates demonstrate anti-inflammatory effects and enhance collagen and muscle fiber synthesis. Overall, these adhesive coacervates with antioxidative and antibacterial properties hold potential as a therapeutic option for oral ulcers in the oral cavity.
Wastewater contains various high-risk trace organic pollutants, such as antibiotics and endocrine disruptors, which seriously restrict wastewater reuse. Cyclodextrin-based functional materials show great potential in the removal of trace pollutants because of their adsorption catalytic synergy. Clarifying the synergistic mechanism of cyclodextrin in oxidation is the key issue in confined catalytic oxidation process design. In this work, we fabricated a BiOIO3@BiOBr/β-CD heterojunction photocatalyst to study the synergistic mechanism of cyclodextrin in the photocatalytic oxidation process. The synergistic mechanism of cyclodextrin was investigated by combining radical chemistry, electrochemistry, spectroscopy, and time-dependent density functional theory. Results showed that the excited intermediate free radicals played an important role in promoting the photocatalytic degradation process. The heterojunction photocatalyst loaded with β-cyclodextrin (β-CD) at the electronic end (C[Cat.] = 0.2 mg/mL) removed about 97% of bisphenol A (BPA) within 30 min, and the first-order kinetic constant (kCDBIB = 0.112 min−1) was about twice that of the unloaded β-CD (kBIB = 0.057 min−1). Cyclodextrin loading improved the photocatalytic performance of the heterojunction and stimulated the intermediate to increase the free radical yield and regulate the reaction path.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
