Catalytic activities of NHC‐PdCl2 species based on functionalized tetradentate imidazolium salt in three types of C‐C coupling reactions

A functionalized tetradentate imidazolium salt 9,10‐bis{di[2′‐(N‐ethylimidazolium‐1‐yl)ethyl]aminomethyl}anthracene tetrakis(hexafluorophosphate) ( 1 ) has been synthesized and characterized. The catalytic activity of the NHC‐PdCl₂ species formed by compound 1 and PdCl₂ was tested in Suzuki‐Miyaura, Heck‐Mizoroki and Sonogashira reactions. The results showed that this catalytic system was effective for above three types of C‐C coupling reactions.     

The protective effect of electroacupuncture on the renal cortex of SHRs: A metabonomic analysis

Hypertension affects multiple organs in the body during the development of the disease. The antihypertensive effect of acupuncture has been confirmed. How the protective effect of electroacupuncture on the renal cortex of the spontaneously hypertensive rat (SHR) is achieved has not yet been determined. The purpose of this study was to understand the impact of electroacupuncture on the blood pressure of SHRs and the impact on metabolites in the renal cortex, looking for potential differential metabolites and then proceeding to the next step of exploratory research. The experimental animals were divided into four groups: control group, model group, electroacupuncture group and losartan potassium group. Electroacupuncture on bilateral Taichong (LR3) and Zusanli (ST36) lasted for 3 weeks, and the renal cortex was collected for metabonomics research. UHPLC–MS was used to analyze the changes in the metabolic spectrum of renal cortex tissue. The results showed that electroacupuncture can significantly reduce the blood pressure of SHRs. A total of 12 metabolites changed significantly in the comparison between each group and the model group.The possible mechanism is that the primary bile acid biosynthesis, bile secretion, tryptophan metabolism and other metabolic pathways affect the renal cortex.     

Mechanically strong and stiff supramolecular polymers enabled by fiber reinforced long-chain alkane matrix

Fiber-reinforced-concrete (FRC) mechanism refers short discrete fibers that are uniformly distributed and randomly oriented, which offers an effective way to improve the mechanical performance of concrete. In the design of supramolecular polymers, an analogous concept of FRC appears to have been considered very rarely-although fibrous structure has been frequently observed/generated during the supramolecular polymerization. In this work, we apply the alkane thermosets, octadecane (C₁₈H₃₈) and tetracosane (C₂₄H₅₀), taking the role of “concrete”, and the low-molecular-weight monomer with long alkyl chains as the essential “fiber” component, to fabricate the “fiber reinforced supramolecular polymer”. Very much like FRC mechanism in material science, the resulting fiber reinforced supramolecular polymer thus exhibit unusually high mechanical strength and stiffness, which is unprecedented in the conventional supramolecular strategy.     

Crosslinked polyaniline nanorods coupled with molybdenum disulfide on functionalized carbon cloth for excellent electrochemical performance

Journal of Solid State Electrochemistry - In this work, the binary nanocomposite of crosslinked polyaniline nanorods (CPANINRs) and molybdenum disulfide (MoS2) is first synthesized by in situ...     

Defect Engineering on Boron Nitride for O2 Activation and Subsequent Oxidative Desulfurization

The rational design of highly active hexagonal boron nitride (h-BN) catalysts at the atomic level is urgent for aerobic reactions. Herein, a doping impurity atom strategy is adopted to increase its catalytic activities. A series of doping systems involving O, C impurities and B, N antisites are constructed and their catalytic activities for molecular O₂ have been studied by density functional theory (DFT) calculations. It is demonstrated that O₂ is highly activated on O_N and B_N defects, and moderately activated on C_B and C_N defects, however, it is not stable on N_B and O_B defects. The subsequent application in oxidative desulfurization (ODS) reactions proves the O_N and C-doped (C_B, C_N) systems to be good choice for sulfocompounds oxidization, especially for dibenzothiophene (DBT). While the B_N antisite is not suitable for such aerobic reaction due to the extremely stable B−O^*−B species formed during the oxidation process.     

In Vitro Antifungal Activity and Mechanism of Ag3PW12O40 Composites against Candida Species

Fungal infections pose a serious threat to human health. Polyoxometalates (POMs) are metal–oxygen clusters with potential application in the control of microbial infections. Herein, the Ag₃PW₁₂O₄₀ composites have been synthesized and verified by Fourier transform infrared (FT-IR) spectrum, transmission electron microscopy (TEM), scanning electron microscope (SEM), elemental analysis, and X-ray diffraction (XRD). The antifungal activities of Ag₃PW₁₂O₄₀ were screened in 19 Candida species strains through the determination of minimum inhibitory concentration (MIC) by the microdilution checkerboard technique. The minimum inhibitory concentration (MIC₅₀) values of Ag₃PW₁₂O₄₀ are 2~32 μg/mL to the Candida species. The MIC₈₀ value of Ag₃PW₁₂O₄₀ to resistant clinical isolates C. albicans HL963 is 8 μg/mL, which is lower than the positive control, fluconazole (FLC). The mechanism against C. albicans HL963 results show that Ag₃PW₁₂O₄₀ can decrease the ergosterol content. The expressions of ERG1, ERG7, and ERG11, which impact on the synthesis of ergosterol, are all prominently upregulated by Ag₃PW₁₂O₄₀. It indicates that Ag₃PW₁₂O₄₀ is a candidate in the development of new antifungal agents.     

Synthesis of a highly active amino‐functionalized Fe3O4@SiO2/APTS/Ru magnetic nanocomposite catalyst for hydrogenation reactions

An amino‐functionalized silica‐coated Fe₃O₄ nanocomposite (Fe₃O₄@SiO₂/APTS) was synthesized. The Fe₃O₄@SiO₂ microspheres possessed a well‐defined core–shell structure, uniform sizes and high magnetization. An immobilized ruthenium nanoparticle catalyst (Fe₃O₄@SiO₂/APTS/Ru) was obtained after coordination and reduction of Ru³⁺ on the Fe₃O₄@SiO₂/APTS nanocomposite. The Ru nanoparticles were not only ultra‐small with nearly monodisperse sizes but also had strong affinity with the surface of Fe₃O₄@SiO₂/APTS. The obtained catalyst exhibited excellent catalytic performance for the hydrogenation of a variety of aromatic nitro compounds, even at room temperature. Moreover, Fe₃O₄@SiO₂/APTS/Ru was easily recovered using a magnetic field and directly reused for at least five cycles without significant loss of its activity.     

Synergistic effect of thermoplastic phenolic resin and multiwalled carbon nanotubes on the crystallization of polyoxymethylene

To reduce the crystallization rate of polyoxymethylene (POM) to meet the requirement of thick-walled and large-sized articles production, and maintain high crystallinity as well as obtain refined crystalline grains to ensure the strength and stiffness simultaneously, thermoplastic phenolic resin (PF) and multiwalled carbon nanotubes (MWCNTs) were used as crystal growth inhibitor and nucleating agent, respectively, and their effects on the crystallization of POM were studied in details. The results showed that PF is an effective inhibitor and MWCNTs exhibits excellent nucleation effect on POM. Based on the obtained results, their synergistic influences on the crystallization process of POM were investigated. It is found that the objective of decreasing the crystallization rate while maintaining high crystallinity and forming fine crystalline grains can be realized. The 97/3/1 wt% POM/PF/MWCNTs, compared with those of neat POM, The T _c shifts by 3.3°C to a lower temperature, the crystallization enthalpy increases by 16.1 J/g and the full width at half-maximum widens by 48.5%. The modulation effect of PF and MWCNTs on the crystallization is closely related to the PF content and dispersion, the distribution and dispersion of MWCNTs in the PF and POM phases.     

Screening potential antagonists of epidermal growth factor receptor from Marsdenia tenacissima via cell membrane chromatography model assisted by HPLC–ESI–IT–TOF–MS

Marsdenia tenacissima, or Tongguanteng in Chinese, is a traditional Chinese herb and has a broad application in clinical practice for its pharmacological effects of treating asthma, pneumonia, tonsillitis, pharyngitis tumors, etc. However, few studies have reported the screening of the active components of this medicine for tumor therapy. In this work, a two‐dimensional analytical system was developed to screen antagonists of epidermal growth factor receptor (EGFR) from M. tenacissima. A fraction was retained on the EGFR cell membrane chromatography (CMC) column, separated and identified as tenacissoside G (TG), tenacissoside H (TH) and tenacissoside I (TI) by two‐dimensional HPLC–IT–TOF–MS. Molecular docking and 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2‐H‐tetrazolium bromide (MTT) assay were carried out to assess the activity of TS (including TG, TH and TI). Molecular docking results showed that the binding mode of TS on EGFR is similar to that of gefitinib. The MTT assay demonstrated that gefitinib and TS (especially TI) could inhibit the growth of EGFR highly expressed cell lines in a dose‐dependent manner in the range of 5–50 μmol/L. In conclusion, the two‐dimensional EGFR/CMC–HPLC–IT–TOF–MS system could be a useful approach in drug discovery from traditional Chinese medicines for searching for potential antitumor candidates.