排序方式: 共有37条查询结果,搜索用时 50 毫秒
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Simon G. Bott Matthew Clark Joseph S. Thrasher Jerry L. Atwood 《Journal of chemical crystallography》1987,17(2):187-196
The X-ray structure of S-methyl(pentafluorosulfanyl)thiocarbamate, SF5NHC(O)SCH3, has been determined from three-dimensional diffractometer data and refined by full-matrix least-squares techniques. The crystals are monoclinic:P21/m,a=5.008 (5),b=7.811 (2),c=9.348 (4) Å, =99.08 (7)°, andZ=2; finalR=0.046 for 517 observed reflections. The structure comprises hydrogen-bonded (NHO) chains with the component monomers in thecis, cis-conformation, i.e., the arrangement of the nonhydrogen and nonfluorine atoms is nearly planar, the SF5 group and the O are in acis position with respect to the C-NH bond, and the O and the CH3 group are in acis position with respect to the C(O)-S bond. Theoretical methods including MNDO and molecular modeling were used to study the relative stabilities of the four possible conformations of SF5NHC(O)SCH3. 相似文献
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Sanford TW Allshouse GO Marder BM Nash TJ Mock RC Spielman RB Seamen JF McGurn JS Jobe D Gilliland TL Vargas M Struve KW Stygar WA Douglas MR Matzen MK Hammer JH De Groot JS Eddleman JL Peterson DL Mosher D Whitney KG Thornhill JW Pulsifer PE Apruzese JP Maron Y 《Physical review letters》1996,77(25):5063-5066
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An integral equation formulation for buoyancy-driven convection problems is developed and illustrated. Buoyancy-driven convection in a bounded cylindrical geometry with a free surface is studied for a range of aspect ratios and Nusselt numbers. The critical Rayleigh number, the nature of the cellular motion, and the heat transfer enhancement are computed using linear theory. Green's functions are used to convert the linear problem into linear Fredholm integral equations. Theorems are proved which establish the properties of the eigenvalues and eigenfunctions of the linear integral operator which appears in these equations. 相似文献
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Reactions of Pentafluorosulfanyldichloroamine The previously unexplored reaction chemistry of pentafluorosulfanyldichloroamine has now led to the novel compounds SF5N?PCl3 and SF5N?SeCl2. Even though both compounds are produced in high yield (>80%), they were found to decompose readily at room temperature. SF5NCl2 has also been found to react with S2Cl2 or SCl2 to give SF5N?SCl2, and with SF5N?SCl2 to give SF5N?S?NSF5. Finally, the adduct SF5NH2 · HCl is formed from SF5NCl2 and HCl. 相似文献
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Lu N Thrasher JS von Ahsen S Willner H Hnyk D Oberhammer H 《Inorganic chemistry》2006,45(4):1783-1788
The synthesis of pentafluoronitrosulfane, SF5NO2, is accomplished either by reacting N(SF5)3 with NO2 or by the photolysis of a SF5Br/NO2 mixture using diazo lamps. The product is purified by treatment with CsF and repeated trap-to-trap condensation. The solid compound melts at -78 degrees C, and the extrapolated boiling point is 9 degrees C. SF5NO2 is characterized by 19F, 15N NMR, IR, Raman, and UV spectroscopy as well as by mass spectrometry. The molecular structure of SF5NO2 is determined by gas electron diffraction. The molecule possesses C2v symmetry with the NO2 group staggering the equatorial S-F bonds and an extremely long 1.903(7) Angstroms S-N bond. Calculated bond enthalpies depend strongly on the computational method: 159 (MP2/6-311G++(3df)) and 87 kJ mol(-1) (B3LYP/6-311++G(3df)). The experimental geometry and vibrational spectrum are reproduced reasonably well by quantum chemical calculations. 相似文献
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Pentacarbonyl Chromium Complexes of SF5-substituted Isocyanides The syntheses of [(F5S? N ? CCF3? NC)Cr(CO)5], [(F5S? N ? CC3F7? CN)Cr(CO)5] and [F5S? N ? C(NCCr(CO)5)2] are reported. The structure of the last-named compound, triclinic, P1 , a ? 640.70(10), b ? 1197.5(2), c ? 1423.5(2) pm, α = 92.560(10), β = 63.410(10), γ = 99.710(10)º, Z = 2, R1 = 0.0512, wR2 = 0.1533, has been elucidated by X-ray diffraction. The analogous tellurium compound is thermally unstable and can not be obtained in substance. 相似文献
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S. M. Sipyagin V. S. Enshov S. A. Kashtanov J. S. Thrasher 《Chemistry of Heterocyclic Compounds》2002,38(11):1375-1381
1-Chloro-2,6-dinitro-4-perfluoroalkylthiobenzenes was obtained in first time by perfluoroalkylation of bis(4-chloro-3,5-dinitrophenyl)disulfide in the presence of xenon bisperfluoroalkylcarboxylates. At the interaction of these compounds with potassium ethylxanthogenate only substitution of chlorine atom occurred. The reaction with sodium N,N-dimethyldithiocarbamate leads to the nucleophilic substitution of nitro group with formation of 1,3-benzodithiol-2-one, but on action of ethyl thioglycolate the intramolecular condensation occurs with formation of benzothiazoles N-oxides. 相似文献