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911.
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
912.
Smirnov B. L. Tubolkin A. E. Britov V. P. Nikolaev O. O. Bogdanov V. V. 《Russian Journal of Applied Chemistry》2004,77(3):493-496
The applicability of the previously developed principles of activating mixing to modification of rubbers in solutions was tested, and a process was developed for mechanochemical modification of cis-1,4-polyisoprene in rotary pulsation apparatus. 相似文献
913.
Method for the synthesis of m-and p-isomers of 4-[2-(ethynylphenyl)vinyl]-2,2,5,5-tetramethyl-3-imidazoline-1-oxyl 3-oxides by the cross-coupling of 4-[2-(3-iodophenyl)vinyl]-and
4-[2-(4-iodophenyl)vinyl]-2,2,5,5-tetramethyl-3-imidazoline-1-oxyl 3-oxides with (trimethylsilyl)acetylene followed by desilylation
was elaborated. The reactions at the CH-fragment of the ethynyl group were performed. The Mannich reaction proceeds with the
loss of a spin label, whereas the oxidative homocoupling, with its retention.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2051–2054, October, 2007. 相似文献
914.
The complete vibrational spectra of crystalline cyclobutanecarboxylic acid have been recorded. A tentative, approximate vibrational assignment is proposed based on these spectra and the infrared spectra of the potassium salt, cyclobutanecarboxylic acid-O-d, cyclobutanecarboxylic acid-α-d-O-d, cyclobutanecarboxylic acid-α-d and previous published results with other simple cyclobutane derivatives. 相似文献
915.
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. |
916.
Published thermodynamic data measured in aqueous mixtures of sodium or potassium dihydrogen phosphate with hydrogen phosphate
and chloride at 25°C were used to test recently developed methods for calculation of the pH of phosphate buffer solutions.
Equations for ionic activity coefficients are used in these methods. It is shown that all data used in the tests up to an
ionic strength of about 0.5 mol-kg-1 can be accurately predicted by the two methods recommended. In one of these methods, equations of the Hückel type are used
for ionic activity coefficients and in the other equations of the Pitzer type. Several sets of phosphate buffer solutions
are recommended,e.g., for calibrations of glass electrode cells. In the recommended sets, the pH of the buffer solutions can be calculated either
by the Hückel or Pitzer method, and the pH predictions of these methods agree in most cases within 0.005 at least up to ionic
strengths of about 0.2 mol-kg-1. The pH values of the two primary pH standards endorsed by IUPAC based on aqueous mixtures of KH2PO4 and Na2HPO4,i.e., pH values of 6.865 and 7.413, can also be accurately predicted by the equations recommended in this study. 相似文献
917.
S. Nakhar I. G. Tishchenko O. N. Bubel' V. I. Biba 《Chemistry of Heterocyclic Compounds》1987,23(7):809-812
Mixtures of stereoisomeric 2-diethoxymethyl-5-ethyloxazolidines with one of the stereoisomeric forms predominating were obtained by the reaction of 2-ethyl-2-formyloxirane diethyl acetal with alkyl-substituted Schiff bases in ethanol solution.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, 985–988, July, 1987. 相似文献
918.
A new phase CrTe3 was discovered and its existence was confirmed by differential thermal analysis and X-ray investigations. Symmetry and lattice parameters as well as the temperature of its peritectic decomposition were determined.
Über die PhaseCrTe 3
Zusammenfassung Eine neue Phase CrTe3 wurde entdeckt und ihre Existenz wurde mittels differential-thermoanalytischer und röntgenographischer Untersuchungen sichergestellt. Es wurden Symmetrie und Gitterparameter sowie auch die Temperatur des peritektischen Zerfalls bestimmt.相似文献
919.
M. G. O. Santana-Marques A. J. V. Ferrer-Correia K. A. Caldwell M. L. Gross 《Journal of the American Society for Mass Spectrometry》1993,4(10):819-827
Aromatic β-hydroxyoximes undergo unusual fragmentation reactions as protonated or cationized species, as radical cations, or as (M - H)? ions, As protonated species, they expel OH ’ from the oxime functionality in violation of the even electron rule. Parallel eliminations of alkyl radicals follow OH’ loss when the aromatic ring is substituted with an alkyl chain. Alkyl radical losses appear to be characteristic of radical cations that can isomerize to ions in which the alkyl chain bears a radical site and the charged site is the conjugate acid of a basic functionality (e.g., oxime or imine). Evidence for the mechanisms was found in the ion chemistry of oxime and imine radical cations. The imine reference compounds were conveniently generated by fast atom bombardment-induced reduction of oximes, removing the requirement for using conventional chemical synthesis. Protonated imines and the (M - H)? ions of oximes fragment extensively via charge-remote processes to eliminate the elements of alkanes. This chemistry is not shared by the protonated oximes. 相似文献
920.
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