Latest ArticlesTwo series of sulfur-containing diarylbenzopyrimidines are designed by the fragment combination of a thioacetamide with our previous disclosed DABP 3 and further oxidation. The best compound 6e with a sulfonyl scaffold displayed EC50 values of 0.0356 μmol/L against WT and 0.0228 μmol/L against HIV K103N mutant strain. More pronounced, it had a lower cytotoxicity (CC50=99.6 μmol/L), higher selectivity index (SIWT=2799, SIK103N=4375) and better calculated logarithm of the octanol-water partition coefficient (cLogP) than the lead compound 3. Molecular docking and dynamics provided the binding modes of these compounds with reverse transcriptase, explaining their activity. Collectively, the new compounds could be candidates for anti-HIV drug discovery.
Carbon dots have unique advantages in biological applications owing to their excellent optical properties. However, the biosafety evaluation of carbon dots has limitations owing to cytotoxicity in vitro, and there is little pre-safety evaluation before in vivo and clinical applications. Whether the carbon dots are or not suitable for applications in vivo, evaluation analysis can be made based on hemolysis and changes in erythrocyte morphology. In this work, a green fluorescent N, S-doped carbon dots (N, S-CDs) were obtained by hydrothermal method, tobias acid, and m-phenylenediamine as precursors. N, S-CDs not only possessed excellent dispersibility, uniform particle size, high quantum yield (37.2%) and stable photoluminescence property but also retain their photostability and strong fluorescence intensity in the acid/alkaline solutions, different ionic strengths (NaCl) and under 365 nm UV illumination. Moreover, the N, S-CDs displayed low cytotoxicity and high cellular uptake efficiency in human umbilical vein endothelial cells (HUVEC) and excellent blood compatibility to the erythrocyte. It is foreseeable that N, S-CDs could be further studied as a promising biological imaging agent in vivo.
Developing enzyme-free sensors with high sensitivity and selectivity for H2O2 and glucose is highly desirable for biological science. Especially, it is attractive to exploit noble-metal-free nanomaterials with large surface area and good conductivity as highly active and selective catalysts for molecular detection in enzyme-free sensors. Herein, we successfully fabricate hollow frameworks of Co3O4/N-doped carbon nanotubes (Co3O4/NCNTs) hybrids by the pyrolysis of metal-organic frameworks followed by calcination in the air. The as-prepared novel hollow Co3O4/NCNTs hybrids exhibit excellent electrochemical performance for H2O2 reduction in neutral solutions and glucose oxidation in alkaline solutions. As sensor electrode, the Co3O4/NCNTs show excellent non-enzymatic sensing ability towards H2O2 response with a sensitivity of 87.40 μA (mmol/L)-1 cm-2, a linear range of 5.00 μmol/L-11.00 mmol/L, and a detection limitation of 1 μmol/L in H2O2 detection, and a good glucose detection performance with 5 μmol/L. These excellent electrochemical performances endow the hollow Co3O4/NCNTs as promising alternative to enzymes in the biological applications.
Considering the importance and complexity of benzene oxidation on mineral oxide aerosol surfaces in the atmosphere, gas-phase 3d-transition metal oxide cations were used as models of active sites on mineral oxide aerosols to mimic the corresponding reactions. The various cations have been prepared by laser ablation and reacted with benzene in a linear ion trap reactor. Of the 103 systematically investigated cations, 39 clusters can oxidize benzene at room temperature. In addition to the adsorption channel, other five types of reaction channels were observed, including dehydrogenation of C6H6, charge exchange, hydrogen atom transfer, oxygen atom transfer, and the formation of C6H5O·radical, among which the first two pathways are prevalent and the formation of C6H6O+ cations has not been reported in literature. The insight into the benzene oxidation reactions derived from the gas-phase model systems is helpful to build a detailed picture of oxidative mechanisms of C6H6 and its derivatives over corresponding mineral oxide aerosols.
In this paper we report the desgin and synthesis of dihydroxyindoles oligomers based reversible fluorescence sensor. We find dihydroxyindoles-2-carboxylic acid derived oligmer (P-DHICA) has the highest selectivity and sensitivity for Cu2+ detection. This work provide a highly efficient, environmentally friendly biosensor for potential use in medical testing.
A novel near-infrared light photothemal-activated H2S-donating nanocomposite hydrogel was developed, through combination of a thermo-labile H2S donor and photothermal nanoparticles in agarose hydrogel. The polyethylenimine dithiocarbamate polymer, a thermo-labile compound, was synthesized as a novel H2S donor. The combination of a thermo-labile hydrogen sulfide donor and photothermal nanoparticles enabled the generation of H2S in agarose hydrogel upon irradiation with near-infrared light. The ability to modulate the photoirradiation for controlled generation and spatiotemporally release of H2S are its specific advantages. This photothermal spatiotemporally controlled H2S-releasing strategy was successfully applied to anti-inflammation treatment in a rat model, demonstrating its utility as a novel H2S-based therapeutic approach.
Nitrogen photofixation using g-C3N4-based photocatalysts have attracted abundant of attentions recently. Herein, in this study, holey g-C3N4 (HGCN) nanosheets possess a good deal of carbon vacancies were prepared by means of thermally treating bulk g-C3N4 (BGCN) under an NH3 atmosphere. Characterization analysis revealed that the as-synthesized sample have identical crystal structure, larger BET specific surface area, stronger reduction capability, and higher photogenerated charge carrier separation rate than that of BGCN. These properties may contribute to enhance the nitrogen photofixation activity. It was also found that the rate of NH4+ production for N2 photofixation of HGCN sample reached~25.54 mg L-1 h-1 gcat-1, which is approximately~5.87 times higher than that of BGCN sample under optimal reactive conditions. Moreover, a plausible mechanism of HGCN for nitrogen photofixation process was illuminated in detail.
Electronic polarization has an important impact on the site energies of charge carriers that play a key role in determining the charge transport in organic semiconductors. Dipolar molecules have strong intermolecular interactions and widespread applications in organic optoelectronics. However, compared with nonpolar organic semiconductors, electronic polarization for dipolar systems has been rarely studied. Here, taking 1, 2, 3, 4-tetrafluoro-6, 7-dimethylnaphthalene as representative, we have calculated the electronic polarization energies of dipolar organic molecular crystals by means of a polarizable forcefield method. Surprisingly, our results point to that the polarization energies for this dipolar system are similar to those of nonpolar systems. In addition, the π-π stack contributes only about 30%~40% to the total polarization energy, thus the polarization effects along the three dimensions should be treated equally even for the one-dimensional stacking crystals.
The temperature-dependent structural changes in 1-butyl-3-methylimidazolium tetrafluoride ([Bmim]FeCl4) magnetic ionic liquid (MIL) were investigated by using in-situ X-ray absorption fine structure (XAFS) combined with Raman spectroscopy and DFTcalculations. XAFS results revealed that the coordination number and bond length of Fe-Cl in the anion of[Bmim]FeCl4 MIL decreased with increments in temperature. These results directly reflected the dissociation of tetrahedral structure[FeCl4]-, and the formation of bridge-chain[Fe2Cl5]+, and[FeCl2]+ species in the anion of[Bmim]FeCl4 MIL. These behaviors indicated that[FeCl4]- dissociation was endothermic, and was promoted by increased temperature. The results obtained through XAFS were in agreement with those obtained through Raman spectroscopy and DFT calculations.
A promising biomass carbon material, manufactured by the carbonation of Physalis peruviana L. calyx at 700 ℃, is presented in this work. Morphology characterization shows that the carbon material possesses long microtubule bundling and above 30% natural O-atom component on the surface. After KOH chemical etching, the materials maintain the oxygen content but exhibit more micropores and higher specific surface area up to 1732.6 m2/g. Using as an electrode material for supercapacitor, the active carbon material exhibits high specific capacitance up to 339.7 F/g at 0.5 A/g in 3 mol/L KOH aqueous solution through three-electrode system. The active carbon material also exhibits excellent cycling stability (97% retention) by 10, 000 cycles at 10 A/g. The outstanding electrochemical performances are attributing to the unique long microtubule bundling with much more pores and the abundant O element on the surface. This biomass carbon material with excellent electrochemical properties could be a useful material for multiple applications.
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