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51.
52.
Sengupta Soumitra K. Pandey Om P. Srivastava Bimal K. Sharma Vinod K. 《Transition Metal Chemistry》1998,23(4):349-353
The reactions of bis(cyclopentadienyl)titanium(IV)/zirconium(IV) dichloride with a new class of organometallic thiosemicarbazones (LH), derived by condensing acetylferrocene with substituted thiosemicarbazides, have been studied and two types of bimetallic products, viz. [Cp2M(L)Cl] (M = Ti or Zr) and [CpZr(L)3], have been isolated. On the basis of various physicochemical and spectral studies, five- and seven-coordinate structures have been assigned to these derivatives, respectively. Attempts have been made to establish a correlation between biological activity and the structures of the products. 相似文献
53.
Summary A satisfactory TLC separation scheme for 15 important amino acids on silica gel layers impregnated with pyridinium tungstoarsenate using isoamyl alcohol-wateracetic acid (605030) as the solvent system has been worked out. It is found that the Martin relationship is obeyed by similarly constituted amino acids. A plot of RM vs the concentration of pyridinium ion released shows a scatter suggesting that, besides exchange properties, other factors also strongly influence the movement of amino acids. 相似文献
54.
IR relative integrated intensities and half-widths of rocking (R) and wagging (W) bands of water in MnCl2 · 2H2O and CoCl2 · 2H2O are presented at 300 K and 120 K. Departure of observed intensity into DW/DR from those predicted by the fixed dipole model is attributed to anisotropic dynamic changes in dipole during these oscillations. A quantity representing the variation of this anisotropy between W and R oscillations is computed and its origin is discussed. An increase by 20% to 50% in both DW and DR on lowering the temperature has also been discussed. 相似文献
55.
56.
Summary A relatively simple procedure for the isolation and determination of the prostaglandins present in human seminal fluid is described. It involves preliminary chromatographic purification of these compounds from the major non-prostaglandin impurities followed by their total elution in one solvent (one-step elution). The prostaglandins thus obtained were almost free from other lipids and were further resolved into prostaglandin-groups and individual prostaglandins by repeated thin-layer chromatography. Data are also presented for prostaglandin contents of fresh semen samples from five individuals and results compared with those from the stored samples.
Einfaches Verfahren zur chromatographischen Isolierung und Bestimmung von Prostaglandinen aus menschlichem Sperma
Zusammenfassung Das Verfahren umfaßt eine chromatographische Abtrennung der Verbindungen von den hauptsächlichsten Verunreinigungen und die Gesamtelution mit einem Lösungsmittel. Die von anderen Lipiden fast völlig freien Prostaglandine werden durch wiederholte Dünnschicht-Chromatographie in Gruppen und Einzelverbindungen getrennt. Werte werden angegeben über die Prostaglandingehalte von frischem im Vergleich zu gelagertem Sperma.相似文献
57.
Summary Electroosmosis of acetone, water and their binary mixtures through thorium oxide (ThO2) plug membrane has been studied and the data analysed using non-equilibrium thermodynamics. The phenomenological coefficients,L
11 andL
12 have been found to vary nonlinearly with composition. Excess phenomenological coefficients have therefore been evaluated and the results explained in terms of the membrane permeant and permeant-permeant interactions. The results on the measurement of electrophoretic velocity of ThO2 particles dispersed in acetone-water mixtures also lead to the conclusion that the components of the mixture interact appreciably.
With 8 figures and 1 table 相似文献
Zusammenfassung Die Elektroosmose von Aceton, Wasser and deren binären Gemische durch eine ThO2-Pflock-Membran wurde untersucht; die Daten wurden mit Hilfe der Nichtgleich-gewichts-Thermodynamik analysiert. Die phänomenologischen KoeffizientenL 11 undL 12 ändern sich hiernach nichtlinear mit der Zusammensetzung. Es wurden daher Exzess-L 11-und -L 12-Werte berechnet; die Ergebnisse wurden auf Grund der Membran-Permeant- und Permeant-Permeant-Wechselwirkungen diskutiert. Aus der Messung der elektrophoretischen Geschwindigkeit von ThO2-Teilchen, die in Aceton-Wasser-Gemischen dispergiert sind, folgt, daß eine merkliche Wechselwirkung zwischen den Komponenten der Mischung vorliegt.
With 8 figures and 1 table 相似文献
58.
Thiotropolone forms chloroform-soluble reddish-brown and violet complexes with cobalt(II) and nickel(II), in the pH range 7.0-8.5 and 6.0-9.0 respectively. Based on this, a sensitive and rapid method for the spectrophotometric determination of traces of cobalt and nickel in metals and alloys has been developed. The two metals can be determined accurately in the range 0.6-2.6 ppm of cobalt and 0.75-4.57 ppm of nickel, simultaneously. 相似文献
59.
The force constants, Coriolis coupling constants and mean amplitudes of vibration at 0, 298.16 and 500 K for GaF63?FeF63? have been reported for the first time employing recent vibrational data. The results are discussed in the light of available information. 相似文献
60.
Summary Nitrosochromotropic acid gives a violet coloured soluble complex with CuII in ammonium chloride-ammonium hydroxide buffer solution, which is less stable than CuII-EDTA complex. When microquantities of CuII solution containing 1 or 2 drops of nitrosochromotropic acid in the ph range 7.25 to 8.00, are titrated with EDTA, a sharp colour change from violet to orange occurs at the end point. The method of titration can be carried out from 20° to 40° C, but the copper complex dissociates at higher temperature and gives low results. The separation of Zn2+, Cd2+, Co2+, Ni2+, Pb2+ and alkaline earths, is necessary as they interfere in the titrations with EDTA.
Zusammenfassung Nitrosochromotropsäure bildet mit Kupfer(II) in Ammoniumchlorid-Ammoniak-Pufferlösung einen violett gefärbten löslichen Komplex, der weniger stabil ist als der Kupfer(II)-ÄDTA-Komplex. Mikromengen Kupfer(II) können imph-Bereich von 7,25–8,00 unter Zusatz von 1–2 Tropfen Nitrosochromotropsäurelösung als Indicator mit ÄDTA-Lösung titriert werden, wobei am Endpunkt ein scharfer Umschlag von Violett nach Orange erfolgt. Die Temperatur der Lösung soll 20–40° C betragen; bei höherer Temperatur erhält man zu niedrige Werte, da der Kupferkomplex dann dissoziiert. Zn2+, Cd2+, Co2+, Ni2+, Pb2+ und Erdalkalien müssen vor der Titration abgetrennt werden.相似文献