Latest ArticlesAqueous zinc-ion batteries are highly favored for their enhanced safety and reduced cost. However, there exist challenges including zinc dendrite, hydrogen evolution, and surface corrosion to be solved. Using electrolyte additives is a highly convenient approach to solving zinc anode-related issues. Inspired by industrial corrosion protection, a trace amount of the corrosion inhibitor urotropine (URT) is used as an electrolyte additive to protect the zinc anode. Theoretical calculation and experimental analysis confirm the adsorption of URT molecules onto the surface of Zn, which inhibits hydrogen evolution. This adsorption further leads to the formation of an inorganic-organic bilayer solid electrolyte interface (SEI) on the surface of the zinc anode, effectively protecting the Zn anode from corrosion, hydrogen evolution and zinc dendrites. The presence of SEI enables symmetrical Zn//Zn cells to exhibit a long cycling performance of 1750 h at 1 mA/cm2 and an average coulombic efficiency of 99.0% at 1 mA/cm2 in Zn//Cu cells. After being coupled with polyaniline (PANI), the Zn//PANI full battery displays excellent cycle stability and specific capacity.
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.
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.
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.
Herein, we describe a nickel-catalyzed reductive decarboxylative difluoromethylation reaction of alkenes using inexpensive and easy-to-handle difluoroacetic anhydride (DFAA)/pyridine N-oxide reagent system. A variety of C(sp3)-CF2H containing compounds were prepared through a hydrodifluoromethylation process. Besides, various gem–difluoroalkenes bearing CF2H group were synthesized via defluorinative reductive cross-coupling process from trifluoromethyl-substituted alkenes using this new reaction system. Difluoroacetic anhydride has been then extended to other common alkyl anhydrides, and the corresponding hydroalkylation and defluoroalkylation processes have been successfully achieved. This method features broad substrate scope, good functional group tolerance as well as high efficiency.
3-Deoxy-D-manno-oct-2-ulosonic acid (Kdo) is widely distributed in bacteria, and the synthesis of Kdo-containing oligosaccharides is important for the development of novel antibiotics and immunological agents. We have recently developed a strategy to achieve α-stereocontrolled glycosylation using a C3-p-tolylthio-substituted Kdo phosphite donor. The wide substrate scope and high reactivity of the donors enabled the efficient synthesis of a series of Kdo-containing glycosides with complete α-stereoselectivity and without the formation of 2,3-ene byproducts. In this study, we improved the method by replacing the leaving group diethyl phosphite with fluoride, which enhanced the stability of the donor and led to cleaner reaction. Furthermore, the substrate range was expanded by synthesizing a series of Kdo O/C/S/N-glycosides, which also opened up a new avenue for the synthesis of CMP-Kdo synthase inhibitors.
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.
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.
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.
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