Latest ArticlesTransition-metal-catalyzed decarboxylative and CH functionalization strategy for the construction of Csp2-Csp2, Csp2-Csp, and Csp2-Csp3 bonds has been extensively studied. However, research surveys of this synthetic strategy for the Csp3-Csp3 bond forming reactions are surprisingly scarce. Herein, we present an efficient approach for the rapid formation of Csp3–Csp3 bond through copper-catalyzed decarboxylative Csp3–H functionalization. The present method should provide a useful access to C3-substituted indole scaffolds with possible biological activities. Mechanistic experiments and DFT calculations supported a dual-Cu(Ⅱ)-catalytic cycle involving rate-determining decarboxylation in an outer-sphere radical pathway and spin-crossover-promoted CC bond formation. This strategy offers a promising synthesis method for the construction of Csp3–Csp3 bond in the field of synthetic and pharmaceutical chemistry and extends the number of still limited copper-catalyzed decarboxylative Csp3–Csp3 bond forming reaction.
Oxygen vacancy induced photothermal effect is of great significant but lack of adequate attentions for environmental remediation. In this paper, green recyclable ZnO/ZnFe2O4 with oxygen vacancy was prepared by a solvothermal-calcination method. The UV-vis light capture ability of ZnO/ZnFe2O4 microspheres is improved with the multiple light reflections due to the yolk-shell structure, and the oxygen vacancy expands the absorption range of photocatalyst and enhances photothermal conversion. The optimized photocatalyst can heat the solution from room temperature to 70 ℃ within 60 min of visible light illumination, and the light to heat conversion efficiency is achieved by 61.3%. Compared with the degradation efficiency at 20 ℃, photothermal catalysis achieves a stable degradation in 80 min, and the degradation efficiency is increased by 41.5%. This can be attributed to the fact that light induced thermal energy accelerates the migration of electrons and holes, and promotes the diffusion of free radicals by heating active centers in situ. The active species contributing to the degradation, in order of importance, are the superoxide radical, hydroxyl radical, hole and electron. The light-to-thermal assisted photocatalysis with ZnO/ZnFe2O4 provides a new sight for the pollution control in the future practical applications.
Pulmonary delivery is an effective drug delivery strategy for the treatment of local respiratory diseases. However, the rapid systemic absorption through the lung due to the thin barrier and persistent lung clearances influence the drug retention in the lung. In this study, we designed a lipid-coated genistein nanocrystals (Lipo-NCs) formulation to achieve enhanced efficiency of local pulmonary delivery. The Lipo-NCs were fabricated by modifying genistein nanocrystals (NCs) with phospholipid membrane through thin film hydration following the homogenization method. The prepared Lipo-NCs exhibited a decreased drug release rate compared with the naked NCs. Our results demonstrated that intracellular uptake and transcellular transport of NCs by the Calu-3 epithelial layer were reduced after lipid coating. Furthermore, the macrophages clearance was also impeded by this Lipo-NCs formulation. In vivo lung retention and distribution revealed that more genistein was retained in the lung after intratracheal administration of Lipo-NCs. The pharmacokinetic study displayed that the AUC(0-t) values of Lipo-NCs were 1.59-fold lesser than those of the NCs group, indicating a reduced systemic absorption. In conclusion, this research indicated that Lipo-NCs could be a suitable formulation for reducing systemic absorption and macrophages clearance, and thus enhancing drug concentration in lung by pulmonary delivery.
Oral and maxillofacial diseases are a group of high-incidence disorders that affect people's life quality to a great extent, while the wet and highly movable environment of the related regions brings challenges to traditional therapies. Faced with the obstacles of insufficient adhesive strength and ensuing short drug retention time, conventional oral therapeutic agents often have difficulty in achieving their desired efficacy. Oral and maxillofacial wet-adhesive materials have the advantages of excellent wet environment retention, internal stability, plasticity, and clinical potential, thus have become a significant research direction in the field of oral related disorders healing. In the past decade, the development of oral adhesive materials with good wet adhesion has accelerated based on the chemical molecular interaction, physical interlocking, and biological adhesion mechanisms, including biomimetic-inspired materials, naturally derived polymer–based materials and adhesive electrospun fiber films. These fancy wet-adhesive materials can be used for oral mucosal drug delivery, oral vaccination, wound healing, and bone defects treatments. Despite their numerous novel applications, wet-adhesive materials in stomatology still face unresolved challenges from material and biological aspects. Here, advances in designs of oral and maxillofacial wet-adhesive materials are reviewed in terms of design backgrounds, attachment mechanisms, and common classifications. Recent demonstrations of wet-adhesive materials for oral and maxillofacial region medical applications from drug delivery to multifunctional tissue treatments are presented. To conclude, current challenges and prospects on potential applications of oral and maxillofacial wet-adhesive materials are also briefly discussed.
Organic semiconductors are promising candidates as photoactive layers for photoelectrodes used in photoelectrochemical (PEC) cells due to their excellent light absorption and efficient charge transport properties with the help of interfacial materials. However, the use of multilayers will make the charge transfer mechanism more complicated and decrease the PEC performance of the photoelectrode caused by the increased contact resistance. In this work, a PM6:Y6 bulk heterojunction (BHJ)-based photocathode is fabricated for efficient PEC hydrogen evolution reaction (HER) in an acidic aqueous solution. With RuO2 as an interfacial modification layer, the photocathode with a simple structure (fluorine-doped tin oxide (FTO)/PM6:Y6/RuO2) generates a maximum photocurrent density up to −15 mA/cm2 at 0 V vs. reference hydrogen electrode (RHE), outperforming all previously reported BHJ-based photocathodes in terms of PEC performance. The highest ratiometric power-saved efficiency of 3.7% is achieved at 0.4 V vs. RHE.
Spin properties of organic molecules have attracted great interest for their potential applications in spintronic devices and quantum computing. Fe-tetraphenyl porphyrin (FeTPP) is of particular interest for its robust magnetic properties on metallic substrates. FeTPP is prepared in vacuum via on-surface synthesis. Molecular structure and spin-related transport properties are characterized by low-temperature scanning tunneling microscope and spectroscopy at 0.5 K. Density functional theory calculations are performed to understand molecular adsorption and spin distribution on Au(111). The molecular structure of FeTPP is distorted upon adsorption on the substrate. Spin excitations of FeTPP are observed on the Fe atom and high pyrrole groups in differential conductance spectra. The calculated spin density distribution indicates that the electron spin of FeTPP is mainly distributed on the Fe atom. The atomic transmission calculation indicates that electrons transport to substrate is mediated through Fe atom, when the tip is above the high pyrrole group.
Heteroatom doped porous carbon materials have emerged as essential cathode material for metal-air battery systems in the context of soaring demands for clean energy conversion and storage. Herein, a three-dimensional nitrogen-doped carbon self-supported electrode (TNCSE) is fabricated through thermal treatment and acid activation of raw wood. The resulting TNCSE retains the hierarchical porous architecture of parent raw lumber and holds substantial defect sites and doped N sites in the carbon skeleton. Assembled as a cathode in the rechargeable zinc-air battery, the TNCSE exhibits a superior peak power density of 134.02 mW/cm2 and an energy density of 835.92 mAh/g, significantly exceeding the ones reference commercial 20% Pt/C does. More strikingly, a limited performance decay of 1.47% after an ultra long-period (500 h) cycle is also achieved on the TNCSE. This work could offer a green and cost-save approach for rationally converting biomass into a robust self-supporting cathode material for a rechargeable zinc-air battery.
Three eudesmanolide sesquiterpene-phenol hybrids, atramacronoids A−C (1−3), featuring an unusual 6/6/5/5/6 skeleton furnished by forming an unexpected C-8−C-16 linkage, were obtained from the rhizomes of Atractylodes macrocephala. Their structures and absolute configurations were elucidated by spectroscopic data analysis, chemical calculations, combined with X-ray diffractions. The plausible biosynthetic pathways for compounds 1−3 are proposed. Surprisingly, compound 1 exhibited cytotoxicity against SGC-7901 cells by inducing cells apoptosis, which might relate to the promotion of synthesis of neutrophil elastase.
A novel atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry (AP-MALDI-MS) method was established for the facile detection of pesticides in ambient environment. Four kinds of multi-walled carbon nanotubes (MWCNTs)-based matrix were synthesized and utilized to enhance the ionization efficiency of pesticides. Organophosphorus, anilinopyrimidine, carbamate, triazine, triazole and benzimidazole pesticides were directly desorbed and ionized from MWCNTs-based matrix in ambient environment, showing clear background and good sensitivity. In a comparison, Fe3O4-doped MWCNTs improved the intensity of pesticide ions more than the other three matrices. Moreover, MWCNTs-based matrix exhibited better performance than organic matrix. Quantitative analysis of pesticides using AP-MALDI-MS was validated to be adequate linearity, repeatability and sensitivity. Overall, AP-MALDI-MS combined with MWCNTs-based matrix enables the directly qualitative and quantitative analysis of pesticides in ambient environment.
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