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In the crystal structure of (CH2C1)2P(O)CH3 and the isomorphous crystal structures of (CH2Br)2P(O)CH3 and (CH2I)2P(O)CH3, the molecules of the methylbis(halomethyl)phosphine oxide have an identical trans, gauche conformation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1526–1528, July, 1991. 相似文献
5.
V. I. Evreinov V. E. Baulin Z. N. Vostroknutova Z. V. Safronova I. B. Krashakova V. Kh. Syundyukova E. N. Tsvetkov 《Russian Chemical Bulletin》1991,40(9):1759-1766
Stability constants of complexes of alkali-metal cations with oligoethylene glycol diethers RO(CH2CH2O)nR (n=1–5), where R=2-Ph2P(O)C6H4 and 2-Ph2(O)-4-t-BuC6H3P, have been determined conductometrically in a tetrahydrofuran-chloroform mixture (41 by volume). The dependence of complexing ability on a number of monopodand donor centers for Li+ and Na+ has multiple extrema. For K+, Rb+, and Cs+ the complexing abilities steadily increase with the length of the ligand polyether chain. Monopodands based on triethylene glycol and its pyrocatechol analog are highly effective (log K=6.7–7.0) with respect to Li+. The synthesis of ligands with a lipophilic tert-butyl substituent in the terminal group is described.For previous communication, see [1]. The number of the communication in [2] is 5, not 4 as printed in error.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1992–2000, September, 1991. 相似文献
6.
V. V. Azatyan N. M. Rubtsov G. I. Tsvetkov V. I. Chernysh 《Kinetics and Catalysis》2006,47(3):327-332
The interaction of hydrogen atoms with a variety of alkali metal and alkaline-earth metal salts results not only in the recombination of these atoms but also in the displacement, into the gas phase, of free radicals (CaCl·(A 1 P 1/2, B 2 S +) and CaF·(A 2 P)) and metal atoms, including their excited species, which are detected spectroscopically. Transmission spectra indicate that the NaCl surface undergoes metallization when treated with a high-frequency discharge and a rarefied hydrogen flame. Combustion is affected by the gas-phase hydrogen atoms involved in the chain reaction and by the varying composition and properties of the surface. The concentration of Na atoms over the NaCl surface at 770 K is 109?1011 cm?3 in a stream of H atoms at 1 Torr and in the 2H2 + O2 flame at 4 Torr. The concentration of sodium atoms in the 2 P 3/2 and 2 P 1/2 excited states is ~5 × 106?5 × 108 cm?3. The role of the discovered reactions in combustion, pyrolysis, and plasma chemistry is discussed. 相似文献
7.
Electron spin echo modulation effects have been investigated in trans bis(2,2,5,5-tetramethyl-3-imidazoline-3-oxide-1-oxyl-4-il) ethylene biradicals involving 14N or 15N nuclei in different positions. The modulation frequencies are shown to be the nitrogen nuclear transition frequencies in radical fragments at mS = 0 of a triplet electronic spin. Quadrupole splitting parameters for these nitrogen nuclei have been determined. 相似文献
8.
A. N. Bovin V. I. Evreinov Z. V. Safronova E. N. Tsvetkov 《Russian Chemical Bulletin》1993,42(5):912-916
A number of monopodands havingo-diphenylphosphinyl terminal groups were synthesized by alkylating sodium derivatives of oligoethylene glycols witho-(bromomethyl)phenyldiphenylphosphine. The stability constants of the complexes of these ligands with alkali metal cations at 25 °C were determined conductometrically in a THF—chloroform solution (41, v/v). The complexing ability of monopodands with respect to the cations studied increases monotonically as the number of electron-donating sites increases (from 3 to 8) for all of the cations except Li+ and, to some extent, Na+. In the case of Li+ a smooth decrease in the stability of the complexes is observed. The monopodands obtained in this work differ drastically in this regard from their structural isomers, bis[o-(diphenylphosphinylmethyl)phenyl] ethers of oligoethylene glycols, which had been studied previously.For part 10, see ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 952–956, May, 1993. 相似文献
9.
S.A. Dikanov A.V. Astashkin Yu.D. Tsvetkov M.G. Goldfeld 《Chemical physics letters》1983,101(2):206-210
A comparative analysis of electron spin echo modulation effects from 14N nuclei of pyrrole rings for Chla+ and P 700+ has been performed, yielding parameters of quadrupole and isotropic hyperfine couplings with nitrogen nuclei in these paramagnetic centres. 相似文献
10.
The effect of the possible anomalous interaction of a muon with nuclei, due to exchange of the muon and the nucleon, with vector V=0, , , J/, , and 0 mesons, on the level of the mesoatoms is considered. An estimate is carried out of the energy shift of the 2P-1S transition. A comparison of the estimates obtained for the 2P-1S transition energy shift in the mesoatom206Pb with the experimental data does not contradict the presence in the muon of an anomalous interaction with the nucleon, defined by the effective coupling constant
/4 4·10–4.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 75–80, June, 1978. 相似文献