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111.
K L Madhok 《Journal of Chemical Sciences》1982,91(2):165-171
Nicke(II) chloride reacts with N,N′-diarylformamidino-N′-arylcarbamides thiocarbamides and N-benzoylformamidino-N′-arylcarbamides,
thiocarbamides forming complexes of the general formula [Ni (Ar.NH.C (NH) NH.C.X. NH.R)2] Cl2 (R=phenyl, orthotolyl and paratolyl; Ar=benzoyl; X=S,O) and [Ni (R.NH.C.X.NH.C (N.Ph.).NH.Ph.)2] Cl2 (R=phenyl, orthotolyl, paratolyl; Ph=phenyl; X=S, O). The ligands when oxidized with iodine undergo ring closure to related
3,5-diarylamino 1,2,4-thiadiazolidines and 3,5-diarylamino-1,2,4-diazolidines, while the complexes are not susceptible to
oxidation. This confirms the binding in complexes is through sulphur and oxygen of the ligands. 相似文献
112.
In the context of the density functional theory of the local electron density the valence and differential density distribution in crystalline sulfates of M2SO4 (M is Li, Rb, and Cs) and double sulfates of MLiSO4 were calculated using the pseudopotential method in the basis set of numerical atomic pseudo-orbitals. It is shown that in lithium sulfate crystallographically inequivalent oxygen atoms are in different charge states and have a different force of chemical bonding with sulfur. Anions are bonded to each other through lithium atoms that form tetrahedral complexes with oxygen. In rubidium sulfates the electron clouds of the anions overlap and chain structures form. Chemical bonding between the anion and the cation has an ionic nature. These features of the electron structure manifest themselves in double sulfates, where LiO4 complexes that link the anionic chains also form, and heavy metals serve as cations. 相似文献
113.
The effects of sodium dodecyl sulfate on extracellular lipase produced byCandida lipolytica have been studied. The microorganism was grown in culture medium containing different sodium dodecyl sulfate concentrations
added to the culture at different intervals of growth. The extracellular lipase activity was not detected when the treated
culture supernatants were directly tested in Yeast Mold Agar-Triolein-Rhodamine plates, regardless of surfactant addition
time and concentrations. However, after ammonium sulfate precipitation and dialysis, the extracellular lipase activity could
be recovered. Therefore, the surfactant, under the experimental conditions used here, does not seem to be able to inhibit
lipase production, but it does inhibit the enzyme activity because of its presence in the mixture of the reaction. 相似文献
114.
115.
The electrocatalytic oxidation of hydrazine at the aluminum electrode, modified by electroless deposition of nickel pentacyanonitrosylferrate
(NiPCNF) on the surface of the electrode has been studied by cyclic voltammetry, chronoamperometry and rotating disk electrode
voltammetry and the kinetics of the catalytic reaction were investigated. The results were explained using the theory of electrocatalytic
reactions at chemically modified electrodes. It was found that a one-electron charge-transfer process is rate limiting and
that the average values of the rate constant for the catalytic reaction and the diffusion coefficient, evaluated by different
approaches, are 5.2×103 M–1s–1 and 8.5×10–6 cm2s–1, respectively. Further examinations of the modified electrodes show that the modifying layers (NiPCNF) on the aluminum substrate
have reproducible behavior and a high level of stability, after exposing them in air and hydrazine solutions for a long time.
Electronic Publication 相似文献
116.
Veronika Gemmer-Colos und Rolf Neeb 《Fresenius' Journal of Analytical Chemistry》1978,293(4):290-294
Zusammenfassung Kleine Mengen Ni, Cu und Zn in wäßrigen Lösungen können nach Ausschütteln ihrer Dipropyldithiocarbamatochelate gas-chromatographisch bestimmt werden. Arbeitsbedingungen für den 0,01–1 ppm-Bereich werden angegeben. Die Reproduzierbarkeit der Bestimmung wird durch Zusatz eines inneren Standards verbessert.
Dialkyldithiocarbamates as reagents for the gas-chromatographic determination of metalsII. Determination of zinc, copper and nickel as dipropyldithiocarbamato chelates after extraction from aqueous solution
Summary Small amounts of Ni, Cu and Zn in aqueous solutions can be determined by gas chromatography after extraction of their dipropyldithiocarbamatochelates. Working details for the 0.01–1 ppm range are reported. Reproducibility is markedly improved by addition of an inner standard.
Die Untersuchungen wurden in dankenswerter Weise durch Mittel der Deutschen Forschungsgemeinschaft und des Verbands der chemischen Industrie unterstützt. 相似文献
117.
Various types of sodium cellulose sulfate (SCS), dissolved in a 1M LiCl solution, were investigated by alternating current (AC)polarography. The SCS samples differed in the degree of substitution (DS), thedistribution of substituents within the anhydroglucose unit (AGU), and alongthechain, due to the method of synthesis. The goal was to study theelectrosorptionbehavior, characterized by the shape of the desorption wave in the polarogram,as a function of the chemical structure of the SCS samples. The shape of thedesorption wave reflects domains of different substitution. A superimpositionofparameters like DS and pattern of substitution on the electrosorption behaviorwas observed. The AC polarography method described can be used as a tool todistinguish between an even or uneven distribution of substituents along thecellulose chain. 相似文献
118.
氢化物发生石墨炉原位富集直接测定高温镍基合金中碲 总被引:5,自引:0,他引:5
通过选择碲的氢化物发生条件,克服了高含量镍对碲的干扰,把氢化物富集在涂钯石墨管里,然后再原子化,成功地测定了高温镍基合金中碲。 相似文献
119.
120.
M.?H.?Pournaghi-AzarEmail author H.?Nahalparvari 《Journal of Solid State Electrochemistry》2004,8(8):550-557
The use of a zinc substrate as an electrode and the modification of its surface by means of a thin film of platinum-doped nickel hexacyanoferrate (Pt-NiHCF) were developed. The modification conditions of the zinc surface including the electroless deposition of metallic nickel on the electrode surface from NiCl2 solution, chemical derivatization of the deposited nickel to the NiHCF film in 0.5 M K3[Fe(CN)6] solution, and electrochemical penetration of metallic platinum into the modified film are described. The modified zinc electrodes prepared under optimum conditions show a well-defined redox couple due to the [NiIIFeIII/II(CN)6]1–/2–
system. The effects of pH, the alkali metal cation, and the anion of the supporting electrolyte on the electrochemical characteristics of the modified electrode were studied in detail. The diffusion coefficients of hydrated alkali metal cations in the film (D), the transfer coefficient (), and the transfer rate constant for the electron (ks) were calculated in the presence of some alkali metal cations. The electrocatalytic activity of the modified electrode for methanol oxidation was demonstrated. The stability of the modified electrode under various experimental conditions was investigated. 相似文献