Latest ArticlesIn this work, semirigid linkers of the alkyl-thiophene-alkyl structure are developed to construct double-cable polymers. Three alkyl units, propyl (C3H6), hexyl (C6H12), and dodecyl (C12H24), are applied as semirigid linkers, yielding three double-cable polymers: PBC6-T, PBC12-T, and PBC24-T, respectively. PBC12-T which uses C6H12-thiophene-C6H12 linkers is found to exhibit the best device efficiency of 5.56%, while PBC6-T and PBC24-T with shorter or longer linkers yield device efficiencies of only 2.65% and 1.09% in single-component organic solar cells (SCOSCs). Further studies reveal that PBC12-T exhibits higher crystallinity and improved charge transport, resulting in better efficiencies. Our work provides an approach to construct double-cable conjugated polymers with long alkyl linkers, and it shows the importance of the linker length for the photovoltaic performance of SCOSCs.
Aqueous rechargeable ammonium-ion batteries (AIBs) have drew considerable attention because of their capacity for high rates, low cost, and high safety. However, developing desired electrodes requiring stable structure in the aqueous fast ammoniation/de-ammoniation becomes urgent. Herein, an ammonium ion full battery using Cu3[Fe(CN)6]2 (CuHCF) acting to be a cathode and barium vanadate (BVO) acting to be an anode is described. Its excellent electrochemical behavior of Prussian blue analogs and the perfectly matched lattice structure of NH4+ is expected. And the open structure of vanadium compounds satisfies the fast ammoniation/de-ammoniation of NH4+ is also achieved. As a result of these synergistic effects, the BVO//CuHCF full cell retains 80.5 percent of its capacity following 1000 cycling. These achievements provide new ideas for developing low-cost and long-life AIBs.
The scope of stereochemistry recognition usually occurs near the chiral scaffold of a ligand or catalyst. Remote stereocontrol, which can surpass the limits of stereorecognition of remote prochiral centers, has long been a challenging object of great interest in asymmetric catalysis. The current work realized the remote stereocontrol of 1,7-zwitterion intermediates formed from Huang's o-amino aryl MBH carbonates. With simple and easily accessible β-ICD as the bifunctional catalyst, multifunctionalized tetrahydroquinoline derivatives could be synthesized via (4 + 2) cycloadditions with excellent enantioselectivity and diastereoselectivity under mild conditions. The strategy possesses broad substrate scope, and three types of electron-deficient enones are successfully applied. Mechanistic studies disclosed the Lewis base-catalyzed reaction pathway, and H-bonding between the catalyst and enones is crucial for long-range stereocontrol. Scale-up reaction and transformations of the tetrahydroquinoline products demonstrated the potential of this strategy.
Inflammatory bowel disease (IBD) is a refractory chronic intestinal inflammatory disease caused by a malfunction of immune system. As the key immune cells in the intestine, macrophages play an important role in maintaining intestinal homeostasis and tissue repair of the IBD. Pharmacological modulation of macrophage function exhibits the promising therapeutic effect for IBD. In this study, mannose-modified liposomes (MAN-LPs) are prepared for macrophage targeting to improve therapeutic efficiency. Rosiglitazone (ROSI) as an agonist of peroxisome proliferators-activated receptor γ (PPAR-γ) is used as the model drug to fabricate different sized liposomes. The impacts of mannose modification and particle size for macrophage targeting are investigated in cells, zebrafish, and mouse models and the therapeutic effects of the MAN-LPs are evaluated on dextran sulfate sodium (DSS)-induced IBD mouse. Compared to unmodified liposome, MAN-LPs display higher uptake by RAW 264.7 cells and better co-localization with macrophage in zebrafish model. Furthermore, MAN-LPs could effectively accumulate in the inflammatory intestinal sites in IBD mouse model. Most importantly, the targeting ability of MAN-LPs is obviously enhanced with the increasing of particle size, whereas the largest MAN-LPs particles achieve the best anti-inflammatory effect in cells, and a higher therapeutic efficiency in IBD mouse model. Therefore, mannose-modified liposome is a promising strategy for macrophage-targeting in IBD treatment. Particle size of MAN-LPs will affect macrophage targeting ability, as well as the therapeutic effect in-vivo.
Fast Fe(Ⅲ)/Fe(Ⅱ) circulation in heterogeneous peroxymonosulfate (PMS) activation remains as a bottleneck issue that restricts the development of PMS based advanced oxidation processes. Herein, we proposed a facile ammonia reduction strategy and synthesized a novel FeVO3-x catalysts to activate PMS for the degradation of a typical pharmaceutical, carbamazepine (CBZ). Rapid CBZ removal could be achieved within 10 min, which outperforms most of the other iron or vanadium-based catalysts. Electron paramagnetic resonance analysis and chemical probe experiments revealed SO4•−, •OH, O2•− and high valent iron (Fe(Ⅳ)) were all generated in this system, but SO4•− and Fe(Ⅳ) primarily contributed to the degradation of CBZ. Besides, X-ray photoelectron spectroscopy and X-ray adsorption spectroscopy indicated that both the generated low-valent V provides and oxygen vacancy acted as superior electron donors and accelerated internal electron transfer via the unsaturated V−O−Fe bond. Finally, the proposed system also exhibited satisfactory performance in practical applications. This work provides a promising platform in heterogeneous PMS activation.
Methicillin-resistant Staphylococcus aureus (MRSA), the most common pathogen in hospital and community environments, can cause serious and even fatal infections. The antibiotics currently used for clinical treatment of MRSA have developed resistance, and there is an urgent need to develop new antimicrobials to treat infections caused by MRSA strains. Quinoline analogues play an important role in the development of antimicrobials. Herein, we discussed the current development of antibacterial activities of quinoline analogues, mainly for anti-MRSA activity, and their structure–activity relationships (SARs) from the perspective of using the quinoline nucleus to search for novel potential anti-MRSA candidates. Additionally, the mechanisms of some representative quinoline analogues against MRSA were clarified. Altogether, this review could provide further insights for the rational development of quinoline-based antibacterial drugs, especially against MRSA.
Immobilizing enzyme to nano interfaces has demonstrated to be a favorable strategy for prompting the industrialized application of enzyme. Despite tremendous endeavor has been devoted to using gold nanoparticles (AuNPs) as conjugation matrix due to its fascinating physico-chemical properties, maintaining enzymatic activity while circumventing cumbersome modification remains a formidable challenge. Herein, the freezing-directed conjugation of enzyme/nano interfaces was constructed without extra reagent. As the proof of concept, glucose oxidase (GOx) was chosen as model enzyme. The one-pot conjugation process can be facilely completed at −20 ℃ under aqueous solution. Moreover, with the loading of GOx on AuNP at freezing, the enzyme exhibited superior catalytic activity and stability upon thermal and pH perturbation. The mechanism of boosted activity was then discussed in detail. It was found that higher loading density under freezing condition and more enzyme tending to bind AuNPs via Au-S bond were the main factors for the superior activity. More importantly, this methodology was universal and can also be applied to other enzyme which contains natural cysteine, such as horseradish peroxidase (HRP) and papain. This facile conjugation strategy accompanied by remarkable bioactivity expand the possibilities for enzymatic biosensing, microdevice and even drug delivery.
N-formylation of amines, a class of synthetically important reactions, is typically conducted using metal catalysts that are relatively expensive or not readily available and usually needs harsh conditions to increase the reaction efficiency. Here, an efficient continuous microflow strategy was developed for the gas-liquid visible-light photocatalytic N-formylation of piperidine, which achieved a reaction yield of 82.97% and a selectivity of > 99% at 12 min using cheap organic dye photocatalyst under mild reaction conditions. The influence of essential parameters, including light intensity, temperature and equivalents of the gas, additive and photocatalyst, on the reaction yield was systematically studied. Furthermore, kinetic investigations were conducted, exhibiting the dependence of reaction rate and equilibrium yield of N-formylpiperidine on light intensity, temperature and photocatalyst equivalent. The microflow photocatalytic approach established in this work, which realized a markedly higher space-time yield than the conventional batch method (37.9 vs. 0.212 mmol h−1 L−1), paves the way for the continuous, green and efficient synthesis of N-formamides.
Unnatural amino acids (UAAs) have broad applications in pharmaceutical sciences and biological studies. Current synthetic methods for UAAs mainly rely on asymmetric catalysis and often require several steps. There is a lack of direct and simple methods. To address this challenge, we designed the LADA (labeling-activation-desulfurization-addition) strategy: selective labeling and activation of cysteine residues, the photocatalytic desulfurization and the subsequent radical addition to alkenes. Although composed of two steps, it is one-pot synthesis and has advantages such as high functional group tolerance, biocompatible reaction condition, and retained stereochemistry. This highly efficient strategy was successfully applied in the direct synthesis of unnatural amino acids and modifications of peptides with more than 50 examples.
A series of photoinduced palladium-catalyzed 1,3-diene-selective fluoroalkylamination derivatives was rationally synthesized based on diversity-oriented synthesis via cross coupling of 1,3-dienes, amines and fluoroalkyl iodides. The reaction featured good function group tolerance and a broad substrate scope, which could be extended to the late-stage modification of bioactive molecules. Bactericidal activity of all the compounds against Xanthomonas oryzae pv. oryzae (Xoo) was evaluated. Among them, compound E14 showed significant activity against Xanthomonas oryzae pv. oryzae (Xoo) with half maximal effective concentration (EC50) value of 6.61 µmol/mL. In pot experiments, the results showed that E14 could control rice bacterial blight with protective and curative efficiencies of 37.5% and 63.2% at 200 µg/mL, respectively. Additionally, a plausible mechanism for antibacterial behavior of E14 was proposed by electron microscopy, flow cytometry, reactive oxygen species detection, and biofilm assay. In current work, it can promote the development of photoinduced palladium-catalyzed 1,3-diene-selective fluoroalkyl amination compounds as prospective antibacterial agent bearing an intriguing mode of action.