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991.
The emulsifier-free emulsion copolymerization of α-methylstyrene (AMS) and methyl methacrylate (MMA) in the presence of functional monomer acrylic acid (AA) was carried out in batch process, giving birth to sub-100 nm nanoparticles. The kinetics of polymerization was investigated. The morphology and size of particles were monitored by TEM. The influences of the functional monomer AA concentration, initiator ammonium persulfate (APS) concentration, and polymerization temperature were studied. It was found that AMS caused a drastic decrease in both the rate of polymerization and the average degree of polymerization. The activation energy calculated from Arrhenius plot turned out to be 83.6 kJ/mol. 相似文献
992.
H. Huang J. Wang J. Z. Fu L. Q. Wang H. Z. Zhao S. Y. Song L. X. Ji M. Jiang G. Bai G. A. Luo 《Journal of Analytical Chemistry》2013,68(4):348-356
An ultra performance liquid chromatographic method was used for the simultaneous identification and quantification of thirteen main components in Xuebijing Injection, including uridine, gallic acid, guanosine, danshensu, protocatechualdehyde, oxypaeoniflorin, hydroxysafflor yellow A, paeoniflorin, ferulic acid, safflor yellow A, senkyunolide I, senkyunolide H and salvianolic acid B. The chromatographic separation was performed on an Acquity UPLC BEH C18 column (1.7-μm, 2.1 × 100 mm, i.d.) with a gradient elution of acetonitrile and 0.2% acetic acid at a flow rate of 0.4 mL/min. The method was validated for linearity (r 2 > 0.9990), intra- and inter-day precision (RSD < 1.94%), accuracy (91.8–99.7%), recovery (96.8–103.8%), limits of detection (0.16–8.0 ng), and limits of quantification (0.54–26.8 ng). At least eight metabolites in prototype were found in rat plasma and urine after intravenous injection of 4 mL/kg doses of Xuebijing Injection. The proposed method could be utilized to qualify and control Xuebijing Injection to ensure its safety and efficacy in application. 相似文献
993.
H. Xia X. Jiang L. Lin C. Jiang G. Liao 《Russian Journal of Coordination Chemistry》2013,39(12):896-901
Reaction of a macrocyclic copper(II) complex [Cu(L)](ClO4)2 · 3H2O (I) (L = 1,3,10,12,16,19-hexaazatetracyclotetracosane) with a hexapod carboxylate ligand H6TTHA (H6TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetic acid) and a tripod carboxylate ligand H3TATB (H3TATB = 4,4′,4″-S-triazine-2,4,6-triyl-tribenzoic acid) yielded two mononuclear copper(II) complexes [Cu(L)][H4TTHA] · 4H2O (II) and [Cu(L)][HTATB] · 4H2O (III). The complexes I–III have been structurally characterized. The crystal structures of complexes II and III show the copper(II) ion has a distorted pentacoordinate square-pyramidal geometry with two secondary and two tertiary amines from the macrocyclic complex [Cu(L)]2+ and one oxygen atom from the carboxylate ligand group at the axial position. The UV-Vis spectra are utilized to discuss the hydrolysis of the complex II. 相似文献
994.
Zhijia Liu Benhua Fei Zehui Jiang Zhiyong Cai Yan Yu Xing’e Liu 《Journal of Thermal Analysis and Calorimetry》2013,111(1):393-399
Moso bamboo (Phyllostachys pubescens) and sinocalamus affinis (Phyllostachys heterocycla) were used in the research. Thermogravimetry (TG), a combination of TG and Fourier transform infrared spectrometer (TG–FTIR), X-ray diffraction (XRD), and differential thermal analysis (DTA) were used to investigate thermal decomposition of bamboo. The calorific value and smoke release process of both bamboos were also tested, respectively. The results from TG indicated that degradation process of sinocalamus affinis and moso bamboo was similar, but their degradation temperatures were different. The main decomposition occurred in the second step and about 68.70 and 64.63% masses degraded for sinocalamus affinis and moso bamboo, whose temperature of maximum mass loss was 319 and 339 °C, respectively. DTA curve showed that the thermal decomposition of both bamboos was an absorbance heat process. TG–FTIR analysis showed that the main pyrolysis products of both bamboos were similar, including absorbed water (H2O), methane gas (CH4), carbon dioxide (CO2), acids and aldehydes, ammonia gas (NH3). The calorific value of moso bamboo (19,291 J g?1 K?1) was higher than that of sinocalamus affinis (18,082 J g?1 K?1). The initial time of smoke release process of moso bamboo was later, and its maximum smoke density was higher than that of sinocalamus affinis. The difference was probably attributed to different compositions and structure of sinocalamus affinis and moso bamboo. The results from this research are very helpful to better design manufacturing process of bio-energy, made from bamboo, by gasification and pyrolysis methods. 相似文献
995.
996.
997.
Wanhua Lei Dr. Guoyu Jiang Dr. Qianxiong Zhou Dr. Yuanjun Hou Prof. Baowen Zhang Prof. Xuexin Cheng Prof. Xuesong Wang 《Chemphyschem》2013,14(5):1003-1008
Nanoscaled coordination polymers based on biologically prevalent ions have potential applications in drug delivery and biomedical imaging. Herein, coordination polymer nanoparticles of anionic porphyrins, including meso‐tetra(4‐carboxyphenyl)‐porphyrin (H2TCPP4?) and meso‐tetra(4‐sulfonatophenyl)‐porphyrin (H2TPPS4?), and alkaline or alkaline earth metal cations, such as K+ and Ca2+, were constructed in aqueous solution in the presence of cucurbit[7]uril (CB7) or cucurbit[8]uril (CB8). UV/Vis absorption and fluorescence spectroscopy, dynamic light scattering (DLS), scanning electron spectroscopy (SEM), and atomic force microscopy (AFM) were applied to explore the assembly and particle formation of porphyrin anions and metal cations mediated by CBn. The particle size depends on the kinds of CBn and metal cations and their concentrations. The uptake of H2TPPS4? particles by tumor cells (A549 cells) was found to be more efficient than H2TPPS4? at 37 °C, showing the application potential of such assembled particles in biology and medicine. 相似文献
998.
Concise and efficient three‐component domino [4+1+1] carbocyclization to highly substituted fluoren‐9‐one derivatives promoted by K2CO3 has been developed under microwave irradiation conditions. The direct bis‐cyanation and aryl amination residing in fluoren‐9‐one framework were achieved in a one‐pot operation. The reaction proceeds at fast rates and can be finished within 30 min, which makes workup convenient to give good to excellent chemical yields. 相似文献
999.
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
1000.
A new copper and silver‐mediated cyanation of aryl iodides with DDQ as a cyanide source is achieved, providing nitriles with good yields. This new approach represents a safe method leading to aryl nitriles. 相似文献