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1.
正纳米过渡金属磷化物(MP_x,M=Cu,Ni,Fe,等)在电催化,光催化,超级电容器以及锂离子电池等领域具有很大的应用前景~(1–3)。在储锂应用中,过渡金属磷化物的理论容量与磷的含量成正比,因此富磷的过渡金属磷化物最具吸引力。但目前富磷MP_x的合成比较困难,往往需要特殊的合成条 相似文献
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研究Lawesson试剂与含有两个氨基的底物的成环反应,合成了N-P-N型五元、六元磷杂环3a-3b、sa-5b及8a-8b,并讨论了成环机理.初步的生测结果表明,所合成的磷杂环具有一定的除草活性,因此LR的成环反应是合成具有生物活性的磷杂环的新方法. 相似文献
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Dawson型磷钨杂多化合物(HPC)作为多相或均相催化剂,对烯烃环氧化反应极为有效[1]。在HPC中引入钼原子可以提高它的氧化能力;引入过渡元素如铜可以改善其氧化还原反应的可逆性[2]。目前已合成出Nb、Ti、Mn、Fe、Co等多种过渡元素取代的Dawson型HPC[3],并且证明其具有良好的氧化还原催化性能。本文以Na2WO4·2H2O和Na2HPO4·12H2O为原料合成了K10Na2H2P2W16O60,再以其为反应物合成了过渡元素镍、铜取代的磷钨、磷钼钨共三种Dawson型杂多化合物:K14[Ni2P2W16O62]·24H2O、K15H5[Ni(P2W16MoO61)2]·26H2O和K15H3[Cu(… 相似文献
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磷酸化血管紧张素Ⅱ的合成及性质 总被引:2,自引:0,他引:2
蛋白质磷酸化和去磷酸化几乎调节着生命活动的所有过程,包括细胞的增殖发育和分化、神经活动、肌肉收缩、新陈代谢和肿瘤发生等[1],而磷肽则是体现其母体蛋白磷酸化过程结构变化的最好模型[2].磷肽合成的常用方法是将合成好的未被磷酸化的多肽与ATP在磷酸激酶的作用下进行酶法磷酸化,但是该法对于不能被磷酸激酶磷酸化的多肽并不适用.迄今为止,磷肽及其类似物的化学合成仍非轻而易举之事[3,4] 相似文献
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过渡金属催化高选择性膦氢化反应 总被引:1,自引:1,他引:0
本文总结了过去几十年特别是近15年来过渡金属催化下各种含磷-氢键的膦氢化合物对炔烃的高选择性膦氢化反应,详尽叙述了其发现、发展和现状.自1996年来,过渡金属催化高选择性膦氢化反应研究工作发展迅速,各种高选择性膦氢化反应不断开发,目前已具有底物适用范围广、过渡金属催化剂活性高、反应选择性高、原子经济性高、以及能满足不同合成需求等优点,并逐步向反应条件温和化、金属催化剂简单化、无配体化、合成步骤简易化以及原料催化剂成本低价化方向发展.虽然如此,至今仍缺乏关于本研究全面的综述和介绍,希望本文可以弥补文献缺陷,对过渡金属催化高选择性膦氢化反应研究有个客观全面的介绍.过渡金属催化烯烃的不对称膦氢化反应合成碳手性或磷手性的光学活性有机磷化合物作为相关研究中的起步最晚的分支,本文也将作阶段小结. 相似文献
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Ovchinnikov V. V. Sagadeev E. V. Lapteva L. I. Khasieva L. R. Alikberov M. Z. Sitnikova E. Yu. Antipin I. S. Stoikov I. I. Konovalov A. I. 《Journal of Thermal Analysis and Calorimetry》1998,54(1):305-309
The enthalpies of vaporization of different classes of phosphorylated alcohols and amines were determined from their enthalpies
of solution in hexane and carbon tetrachloride. The enthalpies of specific (hydrogen-bond) interaction with the solvents (chloroform
and pyridine) of derivatives containing X-H groups (X=O or N) in the α-position to the P=O group were determined. The results
were explained in terms of the spatial structure of such compounds.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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The standard enthalpies of formation ΔfHo (liq. or cr.) at the temperature T = 298.15 K were measured using combustion calorimetry for benzophenone (A), 1-indanone (B), -tetralone (C), 9-fluorenone (D), anthrone (E) and dibenzosuberone (F). The standard enthalpies of vaporization ΔvHo or sublimation ΔsHo of A-F and 5,7-dihydro-6H-dibenzo[a,c]cyclohepten-6-one (G) were obtained from the temperature function of the vapor pressure measured in a flow system. Enthalpies of fusion ΔmH of solid compounds were measured by DSC. From the enthalpies of formation of the gaseous compounds of A-G the values of their strain enthalpies were derived and structural effects discussed.
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M. M. Moustafa 《Journal of Thermal Analysis and Calorimetry》1997,50(3):463-471
The oxime and Schiff's base of N-furoylphenylhydroxylamine form complexes with Co2+, Cu2+, Zn2+ and Fe3+. These complexes were studied by means of the UV — Vis. spectra of nujol mulls, electron spin resonance (ESR) spectra and magnetic susceptibility to determine their stereochemistry. The complexes were characterized via elemental analyses, molar conductivities and thermogravimetric analyses. Organic reagents were used for the gravimetric determination of Co2+, Cu2+ and Fe3+ through the precipitation of their complexes. The compounds were also used for separation of a binary mixture of Cu2+ and Cu2+. Interferences were studied. 相似文献
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The normal vibrational calculation was carried out on cis-polyacetylene(PA) and its model compound, cis, trans-2, 4--hexadiene. Based on the observed IR and Raman frequencies, force constants relevant to the cis-structure were refined. Finally a force field common for cis-PA, trans-PA and three model moleculaes was obtained. The observed spectra of cis-PA were theoretically assigned and the similarities and differences between the cis-and trans- conjugate systems were discussed on the basis of normal coordinate calculation. 相似文献
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《Analytical letters》2012,45(13):2383-2397
Abstract In this study, the polarographic behaviour and the optimum polarographic conditions for the determination of TNX using DC (direct current), DP (differential pulse), SCAP (superimposed constant amplitude pulse) and SIAP (superimposed increasing amplitude pulse) polarographic techniques are described based on the reduction of enol group of the molecule on the dropping mercury electrode. The experiments were conducted in the aqueous supporting electrolyte solution containing 0.2 M KCl and 0.2 M buffer solution. Single waves were obtained at various pH values. The limiting currents were decreased and E1/2 values were linearly shifted to more negative potentials with an increase in the pH. The system was irreversible at both the acidic and the basic media and it was adsorptional in the acidic medium and diffusional at pH 10.8. The variation in the limiting current was found to be 0.86 μA/°C. Good relations were obtained for DC, DP, SCAP and SIAP polarographic techniques at pH 10.8. The determination of TNX in pharmaceutical preparations, namely Tilcotil® tablets, containing 20 mg of TNX were tested employing DC, DP, SCAP, SIAP polarographic techniques. The results were compared to those of HPLC and the standard deviations (SD) were found to be in the range of 0.14 and 0.22 for the techniques employed for filtered and unfiltered solutions. The polarographic techniques used for the determination of TNX seem to be accurate, rapid and practical. Therefore, the suggested method may be promising in the routine analysis. 相似文献
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The adsorption properties of the new carbon materials, sibunites, which are mesoporous samples with a developed surface of pores, were studied. The isotherms of the adsorption of benzene vapor were determined to estimate the porous structure of these materials. The principal methods for calculating the parameters of the porous structure of sibunites were analyzed. The application of the BET equation even in the presence of a small number of micropores can distort the results, therefore the most suitable method for estimating the surface of mesopores is one that is based on the Dubinin—Zaverina equation. The estimation of the surface of sibunites using water vapor adsorption is demonstrated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1377–1380, August, 1993. 相似文献
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Petr Čársky Rudolf Zahradník Ivan Hubač Miroslav Urban Vladimír 《Theoretical chemistry accounts》1980,56(4):315-328
The title technique was applied to a series of elementary chemical reactions. Second and third order contributions to the correlation energy were computed for the basis sets of the double zeta and double zeta plus polarization quality. Calculated heats of reaction and energies of activation were compared with the experimental data and the results of the bestab initio calculations reported in the literature. 相似文献
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《Analytical letters》2012,45(6):1135-1145
Abstract In this study, the polarographic behaviour and the optimum polarographic conditions for the determination of fluvoxamine using DC, DP and SIAP techniques are described based on the reduction on the DME. The experiments were conducted in the aqueous supporting electrolyte containing 0.2 M KCI, 20% ethanol (v/v) and 0.2 M buffer solution. Single waves were obtained at various pH values. The limiting currents were decreased and E1/2 values were linearly shifted to more negative potentials with an increase of pH. The system was irreversible at both the acidic and the basic medium and was controlled by adsorption at pH 4.2 and by diffusion at pH 8.03. The variation of the limiting current against temperature was found to be 1.1 μA°C. Good calibration relations were obtained for DC (direct current), DP (differential pulse) and SIAP (superimposed increasing amplitude pulse) techniques. The determination of fluvoxamine in a pharmaceutical preparation, Faverin® Tablets containing 50 mg of fluvoxamine, were tested. The results were compared to those of UV-spectrophotometric method. In the analysis of a single 50 mg tablet, the relative standard deviation (Srel) are found to be between ±0.5 and ±1.0 for the techniques employed for filtered and unfiltered solutions. The polarographic techniques used for the determination of fluvoxamine seem to be accurate, rapid and practical. Therefore, the suggested method may be promising in the routine analysis. 相似文献
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Fearon P. K. Bigger S. W. Billingham N. C. 《Journal of Thermal Analysis and Calorimetry》2004,76(1):75-83
The oxidation of (Ti,W)C ceramics have been studied as a part of the program to investigate of properties of powder materials.
Thermogravimetry, derivative thermogravimetry (TG-DTG), and differential thermal analysis DSC have been used in the non-isothermal
study of powder oxidation (Ti,W)C in dry air atmosphere. The powder of crystalline carbide cermets with a ratio of W:Ti equals
0.3 was used in this study. The diagrams were recorded on a sample mass 3.42 mg on the Setaram apparatus in temperatures ranging
from 25 to 1000°C. Seven different heating rates were used. The analytical techniques SEM, WDX, EDX and XRD were used in the
research. The kinetics of the oxidation process was followed by the integral method by applying the Coats-Redfern's approximation.
The kinetic models of particular stages of (Ti,W)C oxidation were evaluated from the dynamic mass losses data. The values
of apparent activation energy E and the pre-exponential factor A of each stage of the oxidation were calculated.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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T. P. Chusova L. N. Zelenina Yu. G. Stenin Z. I. Semenova V. A. Titov 《Russian Chemical Bulletin》2007,56(7):1313-1317
The unsaturated and saturated pressures of gallium trichloride vapor were measured by the static method with membrane-gauge
manometers in wide pressure (0.2–760 Torr) and temperature (313–1071 K) intervals. Scanning calorimetry was used to determine
the thermodynamic characteristics of GaCl3 fusion. The thermodynamic characteristics were obtained for sublimation, fusion, vaporization, and association in the vapor
of GaCl3 molecules. The enthalpies of formation and the absolute entropies of GaCl3 in the liquid and gaseous phases and Ga2Cl6 in the gaseous phase were calculated using literature data.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1266–1269, July, 2007. 相似文献