Latest ArticlesCarbon materials have been used as the support for catalysts in the field of acetylene hydrochlorination, the influence of inevitable oxygen-containing moieties on the reaction is often ignored and the mechanism of the oxygen-doping structure remains ambiguous. Herein, we explored the effect of the oxygen-containing group (C–O–C) in the support on the activity of single-atom dispersed Cu catalysts. By immersing the Cu single-atom catalyst in an alkaline solution, the epoxy species on the carbon support was cleaved to obtain a pure ether species while the Cu site was modified to a more electron-deficient state. The turnover frequency value of Cu/O-FLP catalyst with epoxy groups was 1.6-fold higher than that of alkaline treated catalyst. Our result indicated that the epoxy groups could assist adjacent single-atom Cu sites to synergistically promote the adsorption and cleavage of the reactant hydrogen chloride toward form C–OH and Cu–Cl bonds, and reduce the reaction energy barrier. The presence of electron deficient Cu sites and ether species could induce competitive adsorption of the acetylene and hydrogen chloride, thereby reducing the activity of the catalyst. This study highlights the influence of surface oxygen species and the tunability of the support, providing the foundation for the fabrication of higher-activity Cu catalysts for acetylene hydrochlorination.
Inspired by biological ion channels, numerous artificial asymmetric ion channels have been synthesized to facilitate the fabrication of ionic circuits. Nevertheless, the creation of biomimetic asymmetric ion channels necessitates expensive scientific apparatus and intricate material processing procedures, which constrains its advancement within the realm of ionic devices. In this study, we have devised dynamic asymmetric ion channels with mechanical responsiveness by combining polymers of varying elastic modulus along the longitudinal axis of carbon nanotube fiber (CNTF). The ion rectification can be modulated via the disparate response of CNTF-based ion channels to mechanical stress. We have effectively employed these asymmetric ion channels with mechanical sensitivity in the design of a logic gate device, achieving logic operations such as “AND” and “OR”. The conception of these dynamic asymmetric ion channels with mechanical sensitivity offers a straightforward, cost-effective, and versatile approach for generating ion channels, highlighting their potential application in intricate, highly integrated ionic circuits.
Due to the heterogeneity of tumors, single phototherapy cannot completely ablate tumors and inhibit tumor metastasis. To overcome these, we formulated targeted and multifunctional polymersomes ABC@ICG-IMQ-LHRH (AIRL) that encapsulated Toll-like receptor (TLR) 7/8 agonist imiquimod (IMQ) and photosensitizer indocyanine green (ICG) in the hydrophobic layer as well as bubble-generator NH4HCO3 in the hydrophilic cavity to inhibit the growth of primary and distant tumors, and prevent tumor metastasis through synergistic photoimmunotherapy. The AIRL polymersomes exhibited uniform and stable size, and high drug encapsulation efficiency, acid/reduction/laser responsiveness, excellent photothermal conversion efficiency, effective reactive oxygen species generation, high tumor accumulation. AIRL could be effectively internalized by dendritic cells (DCs), achieve lysosome escape and enhance DCs maturation. The synergistic photoimmunotherapy via AIRL polymersomes remarkably promoted the differentiation and activation of T cells, elevated strong systemic immune response to eradicate primary tumors and inhibit the growth of distant tumors. Simultaneously, the endurable immunological memory prevented tumor metastasis, which provided a promising nanoplatform for the combination therapy of cancer.
Selenium is an essential trace element for humans and animals. As the active center of selenoproteins, the addition of selenium is beneficial to enhance the antioxidant ability. However, the high cost limits the application of organic Se in agriculture animal production. Selenized glucose (SeGlu) is a newly invented organoselenium material with good stability, low toxicity and low cost. This assay found that SeGlu was able to increase selenium deposition in liver of newborn broilers, and enhance the antioxidant capacity of liver by elevating the activities of antioxidant enzymes such as total superoxide dismutase and glutathione peroxidase. This paper as the first example clarifying the mechanism of SeGlu to enhance the antioxidant ability of chicks, shows that SeGlu can be used as an organic selenium enrichment additive for early nutrition of poultry. As a cross-discipline study involving chemistry, biology and agriculture animal science, the work may be beneficial for studies in related fields and prompt the development of the selenium science.
The H-bond promoted electrochemical [2 + 2 + 1] annulation of benzo[d]isothiazole 1,1-dioxides, N-arylglycines and paraformaldehyde for the synthesis of various benzo[d]imidazo[1,5-b]isothiazole 5,5-dioxide derivatives under redox mediator, catalyst and electrolyte-free conditions was developed.
A novel asymmetric [4 + 2] cycloaddition of 2-methylidenetrimethylene carbonate with pyrrolidone-derived enones has been achieved to produce the functionalized tetrahydropyran-fused spirocyclic scaffolds via palladium-catalysis. An array of enantioenriched spiro-pyrrolidine-2,3-diones bearing adjacent quaternary and tertiary stereocenters are obtained in high yields with excellent enantioselectivities (up to 96% yield and 99% ee). The further transformation of the product has been accomplished for the construction of medical interesting β2,2-amino acids and β-lactams. Preliminary mechanistic research was well conducted.
Inkjet printing has emerged as a potential solution processing method for large-area patterned films. During inkjet printing, a single droplet without satellite droplet is required for high-quality film. Herein, we propose a strategy for obtaining a single droplet by adjusting the reduced concentration (c/c*, where c* is the critical overlap concentration) in the range of 1.0–1.5. Droplet formation can be categorized into three distinct regimes: (1) c/c* < 1.0, satellite droplet; (2) c/c* = 1.0–1.5, single droplet; (3) c/c* > 2.0, no droplet. Furthermore, an inertial-capillary balance led to the 2/3-power scaling of the minimum radius with time for the solutions of c/c* < 1.0. However, for the solutions of c/c* = 1.0–1.5, the ligament radius decreased exponentially with time. Moreover, the Weissenberg number was higher than the critical value of 0.5, indicating that the polymer chains underwent coil-stretch transition. The viscoelastic-capillary balance dominated instead of the inertial-capillary balance. The resulting viscoelastic resistance reduced the length of the ligament and increased the velocity difference between the satellite and main droplets. Consequently, a single droplet was formed. In addition, the law can be successfully generalized to various molecular weights, molecular structures and solvents.
Herein, a novel molecular tweezer based on 2,2′-bipyridine-bridged porphyrin subunits was constructed for efficient fullerenes recognition. The syn conformation of the molecule, which was obtained by Zn(Ⅱ) coordination, gives rise to a proper cavity to interact with fullerene guests to form a stable 1:1 complex in toluene solution. It exhibits distinct binding selectivity towards C60 over C70. Moreover, the fullerene recognition capacity can be adequately suppressed by importing H2PO4− to competitively capture Zn(Ⅱ) along with syn-anti conformational conversion. Subsequently, the molecular tweezer regenerated to bind the fullerene by introducing the Ca2+ into the system. Significantly, the association-disassociation process can be switched reversibly and repeatedly.
Long-term excessive intake of nitrite (NO2−) poses a great threat to human health, needing a simple and fast method to detect NO2− in food. Herein, via a simple and feasible strategy, Mn/Yb/Er triple-doped CeO2 nanozyme (Mn/Yb/Er/CeO2) was synthesized for highly sensitive ratiometric detection of nitrite. By doping Mn, Yb, Er into CeO2 lattice structure, Mn/Yb/Er/CeO2 nanozyme showed enhanced oxidase-like activity, obtaining a higher density of oxygen vacancy and a higher ratio of Ce3+ to Ce4+ than that of CeO2. The 3,3′,5,5′-tetramethylbenzidine (TMB) can be effectively oxidized by Mn/Yb/Er/CeO2 to produce the oxidized TMB (oxTMB), showing a significant absorption signal at 652 nm. Additionally, nitrite can react with oxTMB to produce yellow diazotized oxTMB, which is accompanied by an elevated absorption signal at 445 nm and a decreased absorption signal at 652 nm. Thus, based on the oxidase-mimetic activity of Mn/Yb/Er/CeO2 and the diazotization reaction between NO2− and oxTMB, a ratiometric colorimetric assay was established for NO2− detection in food. Furthermore, by integrating Mn/Yb/Er/CeO2 with a smartphone, a colorimetric smartphone-sensing platform was successfully fabricated for visualization and quantitative detection of NO2−. Notably, this two-detection mode showed excellent sensitivity, selectivity, reliability and practicability in monitoring the NO2− in real samples, impling its great potential for food safety.
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