Chemical Research in Chinese Universities最新文献

After the preparation of 1,4-bis(4,5-dihydro-1H-imidazol-2-yl)benzene(bdib), a nitrogen heterocycle with potential coordination manners of both cis- and trans-configuration forms, three complexes, including cis-[Cu₂(bdib)₂(μ-OCH₃)₂]Cl₂·2MeOH(1), trans-[Cu(bdib)(AcO)₂]_n(2), and cis-[Ag₂(bdib)₂](NO₃)₂-2H₂O(3), were successfully self-assembled. Complexes 1 and 2 crystallized in the monoclinic system with P2₁/n space group and complex 3 in the triclinic system with P1 space group.

A new synthesized benzene nitrogen mustard was converted into glycosyl donor-trichloroacetimidate that was glycosylated with p-nitrophenol(glycosyl donors) to form β-lactosyl p-nitrobenzene under the protection of acetyl in a stereoselective manner, was prepared and evaluated for its cytotoxicity towards cultured K562 cell line. Methylthiazoy tetrazolium(MTT) assay, transmission electron microscopy(TEM), flow cytometry(FCM) and immunohistochemistry were utilized to explore the mechanisms of how the compound arrests the growth of HCT-T cells. This new synthesed benzene nitrogen mustard glucoside derivate(BNMGD) presented a lower toxicity to normal cells, but is significantly more toxic to K562 cells compared with nitrogen mustard, meanwhile it can induce the apoptosis of K562 cells. These results indicate that the new synthesized BNMGD can inhibit the growth of K562 cells and induce the apoptosis, and its cytotoxicity towards cultured K562 cell line is much more effective than that of nitrogen mustard.

Precursor decomposition was used for the preparation of VTeO/SBA-15 catalyst for the selective oxidation of propane to acrolein. The catalyst shows a better performance compared with those prepared by conventional impregnant method. A yield of 9.3% of acrolein was achieved with 2% V loadings at 500 °C. XRD, N₂-adsorption, H₂-TPR, Py-IR and XPS measurements were used to unclose the relationship between the structure and performance of the catalyst.

[Co¹¹(phen)₃]₂[{(ZnW₁₂O₄₀)Co¹¹(phen)₂(H₂O)}₂Co¹¹(trien)₂(NaH₂O)₂]·3H₂O was synthesized via hydrothermal technique and characterized with elemental analyses, IR spectroscopy, TGA-DTA, and variable temperature magnetic susceptibility. The compound crystallized in the monoclinic system with the space group P2₁/n, a= 1.8210 nm, b=2.3592 nm, c=2.2932 nm, β=110.31°, V=9.239 nm³, Z=2, R₁=0.0827. The compound consists of two coordination cations, three lattice water molecules, and a macroanion [{(ZnW₁₂W₄₀)Co(phen)₂(H₂O)}₂Co(C₆H₁₈N₄)₂·(NaH₂O)₂]^4- in which each supported Keggin anion [(ZnW₁₂O₄₀Co¹¹(phen)₂(H₂O)]^4- acts as a ligand to coordinate to central bridging Co²⁺ ion via a terminal oxygen atom. Hydrogen bonds are responsible for the construction of 3D architecture of the compound. The compound is paramagnetic with a weak antiferromagnetic interaction(ϑ=−46.796 K).

As an Hg-free lamp using phosphor, the Bi³⁺ and Eu³⁺ co-doped Y₂O₂S phosphors were prepared and their luminescence properties under vacuum ultraviolet(VUV) excitation were investigated. The VUV photoluminescent intensity of Y₂O₂S:Eu³⁺ was weak, however, considerably stronger red emission at 626 nm with good color purity was observed in Y₂O₂S:Eu³⁺,Bi³⁺ systems. Investigation on the photoluminescence reveals that the strong VUV luminescence of Y₂O₂S:Eu³⁺Bi³⁺ at 147 nm is mainly because the Bi³⁺ acts as a medium and effectively performs the energy transfer process: Y³⁺-O^2-→Bi³⁺→Eu³⁺, while the intense emission band at 172 nm is attributed to the absorption of the characteristic ¹S₀-¹P₁ transition of Bi³⁺ and the direct energy transfer from Bi³⁺ to Eu³⁺. The Y₂O₂S:Eu³⁺,Bi³⁺ shows excellent VUV optical properties compared with the commercial (Y, Gd)BO₃:Eu³⁺. Thus, the Y₂O₂S:Eu³⁺,Bi³⁺ can be a potential red VUV-excited candidate applied in Hg-free lamps for backlight of liquid crystal display.

Escherichia coli 3-Deoxy-D-manno-octulosonate 8-phosphate(KDO8P) synthase catalyzed the condensation reaction between D-arabinose 5-phosphate(A5P) and phosphoenolpyruvate(PEP) to form KDO8P and inorganic phosphate(P_i). The noncovalent tetrameric association of KDO8P synthase was observed and dissociated in gas phase by means of electrospray ionization mass spectrometry under the very “soft” conditions. The results indicate that PEP-bound enzyme generated abundant tetrameric species as well as monomeric species at the “soft” conditions, whereas, the unbound enzyme favored the formation of a dimeric species. The mass spectra of the mixture of the enzyme with one of substrates, PEP, and A5P or one of products, KDO8P and P_i show that the complex of the unbound enzyme with PEP or P_i was prone to the formation of a monomeric species, whereas, that of the unbound enzyme with A5P or KDO8P was similar to the unbound enzyme. The intensity of the dimeric species increased with the increase of temperature at a collision voltage of 10 V. Taken together, the results presented here suggest that mass spectrometry will be a powerful tool to explore subtile conformational changes and/or subunit-subunit interactions of multiprotein assembly induced by ligand-binding and/or the changes of environmental conditions.

With the decrease of pH value from 8.45 to −1.0, the UV-Vis absorption and fluorescent spectra of 1,2-bis(4-pyridyl) ethylene(BPE) took on the same changing trend at four different successive pH stages: 8.45—7.20, 7.20—5.62, 5.62—2.60, and 2.60—1.0, namely, no change, decrease, increase, and decrease again. Among these, in a range of 7.20—5.62, the fluorescence wavelength blueshifted from 418 to 359 nm, but the UV-Vis absorption wavelength, in contrast, redshifted from 285 to 298 nm. The fluorescence intensity of BPE had a drop even to quench upon a decline in the pH value from 2.60 to −1.0 probably owing to its cation-π interaction to reduce the π electron cloud density of BPE. Two dissociation constants, pK_a1(4.30±0.01) and pK_a2(5.65±0.04), were obtained based on fluorescence data. The changes of fluorescence spectra indicate that BPE has “off-on-off” switch behavior. The fluorescent spectra of BPE were nearly independent on the presence of α- and β-cyclodextrins.

In view of the anti-HIV activities of delavirdine and resveratrol, a novel anti-AIDs drug Resdelasu, 1-{3-[(1-methyl-ethyl)amino]-2-pyridinyl}-4-{[5-(4-{5[(1E)-2-(hydroxyphenyl)ethenyl]-1,3-benzenedioyl-carbonylbutanoyl}amino)-1H-indol-2-yl]carbonyl}-piperazine was synthesized by linking the delavirdine derivative and resveratrol with succinic anhydride as the conjugated compound via two different routes. Its structure was confirmed by means of ¹H NMR, ¹³C NMR, IR, MS, and elemental analysis. The route of esterification followed by amidation for synthesizing Resdelasu was simpler and gave a higher yield(46%) than that of amidation followed by esterification. It was proved that the method was efficient and convenient to prepare Resdelasu. The results of HIV-1 Reverse Transcriptase Assay and quantitative titration of HIV-1 via MAGI assay showed that a novel anti-AIDs drug, Resdelasu, had been synthesized.

5-Fluorouracil(5-FU) loaded nanoparticles(NPs) were prepared by a high speed shearing double emulsion method with polylactide-co-glycolide-co-methoxy poly(ethylene glycol)(PLGA-mPEG) as loading material. The prepared NPs possess a negative zeta potential and their loading efficiency is about 15%(mass fraction). The result of in vitro release shows that the release behavior of 5-FU from NPs is coincident with Zero-level release from the second day.

Ir catalyst possesses a good electrocatalytic activity and selectivity for the oxidation of NH₃ and/or NH₄OH at Ir anode in the potential fixed electrochemical sensor with the neutral solution. Owing to the same electrochemical behavior of NH₃ and NH₄OH in a NaClO₄ solution, NH₄OH can be used instead of NH₃ for the experimental convenience. It was found that the potential of the oxidation peak of NH₄OH at the Ir/GC electrode in NaClO₄ solutions is at about 0.85 V, and the current density of the oxidation peak of NH₄OH is linearly proportional to the concentration of NH₄OH. The electrocatalytic oxidation of NH₄OH is diffusion-controlled. Especially, Ir has no electrocatalytic activity for the CO oxidation, illustrating that CO does not interfere in the measurement of NH₄OH and the potential fixed electrochemical NH₃ sensor with the neutral solution, and the anodic Ir catalyst possesses a good selectivity. Therefore, Ir may have practical application in the potential fixed electrochemical NH₃ sensor with the neutral solution.