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991.
Dr. Kazuhiko Amakawa Dr. Lili Sun Dr. Chunsheng Guo Dr. Michael Hävecker Pierre Kube Prof. Dr. Israel E. Wachs Soe Lwin Prof. Dr. Anatoly I. Frenkel Dr. Anitha Patlolla Prof. Dr. Klaus Hermann Prof. Dr. Robert Schlögl Dr. Annette Trunschke 《Angewandte Chemie (International ed. in English)》2013,52(51):13553-13557
Highly dispersed molybdenum oxide supported on mesoporous silica SBA‐15 has been prepared by anion exchange resulting in a series of catalysts with changing Mo densities (0.2–2.5 Mo atoms nm?2). X‐ray absorption, UV/Vis, Raman, and IR spectroscopy indicate that doubly anchored tetrahedral dioxo MoO4 units are the major surface species at all loadings. Higher reducibility at loadings close to the monolayer measured by temperature‐programmed reduction and a steep increase in the catalytic activity observed in metathesis of propene and oxidative dehydrogenation of propane at 8 % of Mo loading are attributed to frustration of Mo oxide surface species and lateral interactions. Based on DFT calculations, NEXAFS spectra at the O‐K‐edge at high Mo loadings are explained by distorted MoO4 complexes. Limited availability of anchor silanol groups at high loadings forces the MoO4 groups to form more strained configurations. The occurrence of strain is linked to the increase in reactivity. 相似文献
992.
993.
994.
Wei Sun Linjie Tian Hui Qi Dan Jiang Ying Wang Song Li Junhai Xiao Xiaohong Yang 《中国化学》2013,(9):1144-1152
A series of tri-substituted chiral pyrrolidin-2-one derivatives have been designed and synthesized as CC chemokine receptor 4 (CCR4) antagonists. The structure of CCR4 was built by homology modeling. Asymmetric synthesis was applied to synthesize the R,R configuration chiral pyrrolidin-2-one scaffold. The stereoisomeric con- figurations of the compounds were identified by 2D I H-~H COSY spectroscopy and 1D NOESY spectroscopy. This method was more economical and convenient than traditional X-ray single crystal diffraction. In addition, the inter- actions between these compounds and the N-terminal extracellular tail of CCR4 were studied using capillary zone electrophoresis. The CCR4 chemotaxis inhibition effect was tested in CCR4-transfected HEK293 cells. Several compounds showed potent activities as CCR4 antagonists. Among these compounds, lc is the most active one. Its apparent binding constant of CZE experiment result is (1.569±0.11)× 10s L·mol ^-1, and its percentage inhibition of the HEK293/CCR4 cells migration with the concentration of I gmol·L ^-1 in DMSO is 59%. And compound If has slightly higher affinity to N-terminal of CCR4 according to its apparent binding constant than lb because of the in- troduced ester linkage. Further studies on the mechanism of these compounds are in progress. 相似文献
995.
Hierarchical flower-like architectures of[Ni3(BTC)2·12H2O](BTC3=benzene-1,3,5-tricarboxylate) were successfully prepared by a simple solution-phase method under mild conditions without any template or surfactant.Phase-pure porous NiO nanocrystals were obtained by annealing the Ni-BTC complex without significant alteration in morphology.The product was characterized by X-ray diffraction techniques,field-emission scanning electron microscopy(FESEM).transmission electron microscopy(TEM) and high-resolution TEM(HRTEM).The catalytic effect of the NiO product was investigated on the thermal decomposition of ammonium perchlorate(AP) and it was found that the annealed NiO product has higher catalytic activity than the commercial NiO. 相似文献
996.
A novel chelating resin OABA,capable of removing Cu(Ⅱ) from aqueous solution,was synthesized via the reaction of macroporous chloromethylated PS-DVB copolymer beads with orotic acid.The elemental analysis(EA),Fourier transform infrared spectroscopy(FT-IR),and scanning electron microscopy microscope-energy dispersive X-ray spectroscopy(SEM-EDS) were used in the characterization of the synthesized chelating resin.Multiple,static batch adsorption experiments were conducted at different initial concentrations and temperatures.OABA showed good adsorption capacity for Cu(Ⅱ) and the equilibrium data could be well matched with the Freundlich isotherm model.Coexisting sodium chloride and calcium chloride in solutions favored the Cu(Ⅱ) adsorption.Moreover,the desorption process of Cu(Ⅱ) was tested and over 90%regeneration efficiency for the spent OABA was achieved at ammonia concentrations ranging from 1.0%to 2.0%.The results suggested that OABA would be a potential alternative adsorbent for Cu(Ⅱ),even with other heavy metal ion treatments of wastewater. 相似文献
997.
Yang Sun Zhipeng Ran Hongyan Tang Yong Li Wenshuang Song Qingguang Ren Wuli Yang Jilie Kong 《中国化学》2013,31(6):787-793
Mesoporous silica nanoparticles (MSN) were coated by pH‐responsive polymer chitosan‐poly (methacrylic acid) (CS‐PMAA). This nano drug delivery system showed good application prospects and the polymer‐coated microspheres were promising site‐specific anticancer drug delivery carriers in biomedical field. A continuous detection of pH‐responsive drug delivery system in cells in situ, utilizing MSN/CS‐PMAA composite microspheres, was proposed. Two kinds of different cell lines, tumor cell line (Hela) and normal somatic cells (293T), were used to investigate the behaviours of the drug loaded system in the cells. Conclusions could be drawn from the fluorescent images obtained by confocal laser scanning microscopy (CLSM), modified drug‐loaded microspheres (MSN/CS‐PMAA) were ingested into cells more easily, the uptake of DOX@FITC‐MSN/CS‐PMAA by HeLa/293T cells were performed at pH 7.4/pH 6.8, DOX was released during the ingestion process, fluorescence intensity decreased with time because of efflux transport and photo‐bleaching. Fluoresence detection by flow cytometry was performed as comparison. The continuous fluorescent observation in situ could be widely used in the pH‐responsive releasing process of drug delivery system in the cells. 相似文献
998.
Xiaoyun Qin Wenbo Lu Yonglan Luo Guohui Chang Xuping Sun 《Russian Journal of Electrochemistry》2013,49(11):1092-1096
Graphene platelet (GP)-Ru(phen) 3 2+ assembles have been prepared through self-assembly of poly sodium styrenesulfonate (PSS) functionalized GPs and Ru(phen) 3 2+ driven by electrostatic attraction interactions in aqueous solution. The resultant assembled GP-Ru(phen) 3 2+ hybrid structure modified electrode exhibits excellent electrochemiluminescence (ECL) behaviors because of the ECL active species Ru(phen) 3 2+ contained therein. 相似文献
999.
1000.
This paper presents a microsensor chip integrated with a gold nanoparticles‐modified ultramicroelectrode array (UMEA) as the working electrode for the detection of copper ions in water. The microsensor chip was fabricated with Micro‐Electromechanical System technique. Gold nanoparticles were electrodeposited onto the surface of UMEA at a constant potential of ?0.3 V. The ratio d/Rb of interelectrode spacing (d) over the individual electrode’s radius (Rb) was investigated to improve the electrochemical performance. The UMEA with a d/Rb of 20 showed the best hemispherical diffusion mode, resulted in fast response time and high current response. The gold nanoparticles increased the active surface area of UMEA by not changing the geometries of UMEA, and the current response was increased further. Incorporating the optimized characteristic of UMEA and gold nanoparticles, the microsensor showed a good linear range from 0.5 to 200 µg L?1 of copper ions in the acetate buffer solutions with the method of square wave stripping voltammetry. Compared with the gold nanoparticles‐modified disk electrode, the gold nanoparticles‐modified UMEA showed higher sensitivity (0.024 µA mm?2 µg?1 L) and lower limit of detection (0.2 µg L?1). Water samples from river water and tap water were analyzed by the microsensor chip with recovery ranging from 100.7 % to 107.8 %. 相似文献