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961.
Toy and Stringham recently reported [1] the synthesis of N2F+5 (CF3)3CO-, a salt containing the novel pentafluorohydrazinium cation. This cation would be of significant academic and practical interest [2] since it would constitute the first known example of a substituted NF+4 cation, i.e. an NF+4 cation in which a fluorine ligand is replaced by an NF2 group. According to the authors of [1], N2F+5(CF3)3CO- was formed in a very unusual reaction involving the transfer of a fluorine cation from (CF3)3COF to N2F4 according to: 相似文献
962.
S. Mlinkó I. Gács K. Payer J. Ottinger E. Dobis 《Journal of Radioanalytical and Nuclear Chemistry》1977,35(2):321-331
In this paper an automatic apparatus designed for the radioactivity measurement of14C-labelled organic compounds in the gaseous phase is described. The labelled organic compounds are combusted in a mixture
of argon and oxygen. After combustion the oxygen content of the gas is eliminated by passing it through a copper packing.
The water and heteroelements present are also removed and the radioactive carbon dioxide gas is swept by argon carrier gas
into a piston-type counter tube. In the counter tube the piston forming a dividing wall moves forward in accordance with the
rate of combustion and sweeping, and thus sucks the gases leaving the combustion tube into the effective tube volume. The
anode wire is carried by a reel located in the piston and a spring device ensures its stretched state. At the end of the sweeping
period methane is fed into the counter tube and the activity of the argon—methane—carbon dioxide mixture is measured in the
limited proportional region. Manual and automatic operation is possible. The piston-type counter tube provides possibility
for strandardization by means of extrapolation and for measurement of absolute activities. 相似文献
963.
Triplet state transitions of the photosynthetic bacteria Rhodospirillum Rubrum, Rhodopseudomonas Spheroides and Chromatium Vinosum in chemically reduced preparations have been observed by zero-field optical detection of magnetic resonance at 2 K. For each bacterial preparation two sharp, structureless, zero-field EPR transitions were observed as microwave-induced decreases in the fluorescence intensity of the frozen cellular preparations. The depopulating rate constants for the spin sublevels of the triplet states observed in R Rubrum and R Spheroides were also measured. The similarities of the triplet state frequencies, spectral features and intersystem crossing rates suggest a common structure for the reaction centers in the photosynthetic bacteria. 相似文献
964.
A. I. Skrigan T. V. Murashkevich N. M. Khorevskaya G. N. Pershina N. E. Akimova 《Chemistry of Natural Compounds》1972,5(6):464-467
Conclusions 1. The content of lignin in the wood ofSalix viminalis andSalix acutifolia increases with the growth of the shoots during shortened days and also in drier climatic periods.2. The monosaccharides, glucose, fructose, and arabinose take part in the synthesis of the lignin of young wood ofSalix viminalis andSalix acutifolia. The formation of lignin of one-year willow wood takes place from May to January (with a maximum in June–July). The content of methoxyl groups in it gradually rises.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 6, pp. 546–550, 1969 相似文献
965.
F. P. Sidel'kovskaya V. A. Ponomarenko M. G. Zelenskaya A. V. Ignatenko O. D. Trifonova É. A. Abdula-Zade A. G. Kechina L. A. Sinitsyna 《Russian Chemical Bulletin》1976,25(3):587-593
1. | Some new -oxides were synthesized, which contain a lactam ring in the substituent and have the general structure: where R = H, CH3; OC OC2H5, and Z = CH2, CH2OCH2, (CH2)2OCH2. |
2. | It was shown on the example of the synthesized glycidyl ethers that they are capable of forming polymeric products under the influence of nucleophilic agents, and also of adding water, ammonia, and diethylamine under mild conditions. |
966.
A mordenite-containing rock from the Tokaj-mountains was investigated. The effect of the treatment with hydrochloric acid solutions of various molarity was established. From gas adsorption measurements, scanning electron microscopic investigations and measurements with a mercury porosimeter conclusions were drawn on the changes caused by acid treatment. Slight changes in the texture were found, but no damage in the crystal structure could be observed.
- . . , - , , . - .相似文献
967.
U. Gelius S. Svensson H. Siegbahn E. Basilier Å. Faxälv K. Siegbahn 《Chemical physics letters》1974,28(1):1-7
The line profile of the narrow, symmetric 1s line from neon, recorded with the new ESCA instrument with X-ray monochromatization, is analyzed. The natural linewidth of this line is found to be 0.23 ± 0.02 eV, in good agreement with theoretical calculations of the oscillator strengths for Auger transitions and X-ray emission. Spectra from molecules show frequently asymmetric core electron lines under high resolution. This rules out previous explanations based on a chemical influence on the natural lifetime. Contrary to earlier assumptions, vibrational excitations are shown to be important in core electron spectra. For methane, the vibrational energy spacing is large enough to allow the vibrational lines to be partly resolved. Recent results from accurate PNO CI calculations on methane agree well with the experimental findings. The Franck-Condon transitions in the C1s and N1s lines from CO and N2 are shown to be well described in the harmonic approximation and approximating the potential curves of the highly excited core hole states with the potential curve for the ground state of NO+, X1 Σ+. Knowledge of vibrational excitations in core electron spectra is shown to be valuable in the analysis of high resolution X-ray emission spectra of free molecules. 相似文献
968.
O. Ya. Neiland R. A. Valters G. G. Pukitis V. Zh. Tilika A. S. Edzhinya 《Chemistry of Heterocyclic Compounds》1992,28(9):1079-1083
The conversions of 2-thioxo-1,3-dithiol-4,5-dicarboxylic acid methyl ester into anhydride, mono- and diamide, and monoamide methyl ester were demonstrated. The new heterocyclic system, (4H,6H)-1,3-dithiolo[4,5-d]pyrimidine-2,5,7-trione, was obtained by oxidative rearrangement-cyclization of 2-oxo-1,3-dithiol-4,5-dicarboxylic acid diamide with phenyliodosyl(hydroxy)tosylate and used to synthesize previously unknown 5,6-dimercaptouracil derivatives, including nickel dithiolene complex.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1270–1275, September, 1992. 相似文献
969.
The conditions of thermal decomposition of the 3-chlorobenzoates of Y, La and the lanthanides from Ce(III) to Lu have been studied. The complexes of La, Pr(III), Sm, Eu, Gd, Tb(III) and Dy were prepared as heptahydrates, those of Ce(III) and Y as pentahydrates, that of Nd as the tetrahydrate, that of Ho as the dihydrate and those of Er, Tm, Yb and Lu as anhydrous salts. On heating, these complexes decompose in three or two stages. They first lose some water molecules and then decompose to oxides through the intermediate formation of LnOCl. Cerium(III) 3-chlorobenzoate loses its crystallization water in two stages and yields the anhydrous salt, which is then transformed directly into CeO2. All these complexes melt before decomposition in the temperature range 441–513 K. 相似文献
970.