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71.
A synthesis of 5,11b-dihydro-1H-dibenzo[d,f][1,3]diazepin-1-ones was found in the reaction of nitro-substituted N1,N2-diarylamidines with 3,4,5,6-tetrachloro-1,2-benzoquinone. In contrast, 6,7,8,9-tetrachlorodibenzodioxins were obtained from reaction of N1,N2-diphenylpropionamidine and N1,N2-di-(4-tert-butylphenyl)acetamidine with 3,4,5,6-tetrachloro-1,2-benzoquinone. 相似文献
72.
Alkoxylierung von bis(trimethylsilyl)-aminofluorsilanen,sowie siloxanbildung unter äthereliminierung
Uwe Klingebiel Dietrich Fischer Anton Meller 《Journal of organometallic chemistry》1975,85(2):141-147
The reaction of bis(trimethylsilyl)aminofluorsilanes, (Me3Si)2NSiF2R (R = CH3 or F), with sodium alcoholates or sodium phenylate yields under elimination of NaF alkoxy- and aryloxy-aminofluorosilanes of the composition (Me3Si)2NSiF(R)OR′(R′ = CH3, C2H5, C3H7, C6H5). A disiloxane is formed by thermal elimination of diethyl ether from bis(trimethylsilyl)aminomethylfluoroethoxysilane. The IR, mass, 1H and 19F NMR spectra of the above-mentioned compounds are reported. ab]Die Reaktion von Bis(trimethylsilyl)-aminofluorsilanen des Typs (Me3Si)2NSiF2R (R = F, CH3) mit Natriumalkoholaten und Natriumphenolat führt unter NaF-Abspaltung zu Alkyl- und Aryloxyaminofluorsilanen der Zusammensetzung: (Me3Si)2NSiF(R)OR′ (R′ = CH3, C2H7, C6H5, C6H5). Ein Disiloxan könnte durch die thermische Eliminierung von Diäthyläther aus Bis(trimethylsilyl)aminomethyl-fluor-äthoxy-silylarnin erhalten werden.Die IR-, Massen-, 1H- und 19F-NMR-Spektren der dargestellten Verbindungen werden mitgeteilt. 相似文献
73.
Crystal Structures of Acid Hydrates and Oxonium Salts. XX. Oxonium Tetrafluoroborates H3OBF4, [H5O2]BF4, and [H(CH3OH)2]BF4 The crystal structures of three oxonium tetrafluoroborates were determined. H3OBF4, oxonium tetrafluoroborate proper, is triclinic with space group P1 , Z = 2 and the unit cell dimensions a = 4.758, b = 6.047, c = 6.352 Å and α = 80.40, β = 79.48, γ = 88.25° at ?26°C. Cations H3O+ and anions BF4? are linked by hydrogen bonds O? H…?F into ribbons of condensed rings. In [H5O2]BF4 (diaquohydrogen tetrafluoroborate, monoclinic, P21/c, Z = 4, a = 6.584, b = 9.725, c = 7.084 Å, β = 95.15° at ?100°C) the hydrogen bond in the cation H5O2+ is 2.412 Å short, asymmetric and approximately centered and the linking of cations and anions three-dimensional. In [H(CH3OH)2]BF4 (Bis(methanol)hydrogen tetrafluoroborate, monoclinic, P21/c, Z = 4, a = 5.197, b = 14.458, c = 9.318 Å, β = 94.61° at ?50°C) the cation [H(CH3OH)2]+ is characterized for the first time in a crystal structure with an again very short (2.394 Å), asymmetric and effectively centered hydrogen bond. By further hydrogen bonds cations and anions form only dimers of the formula unit of centrosymmetric cyclic structure. 相似文献
74.
Neumann M Herten DP Dietrich A Wolfrum J Sauer M 《Journal of chromatography. A》2000,871(1-2):299-310
The first capillary array scanner for time-resolved fluorescence detection in parallel capillary electrophoresis based on semiconductor technology is described. The system consists essentially of a confocal fluorescence microscope and a x,y-microscope scanning stage. Fluorescence of the labelled probe molecules was excited using a short-pulse diode laser emitting at 640 nm with a repetition rate of 50 MHz. Using a single filter system the fluorescence decays of different labels were detected by an avalanche photodiode in combination with a PC plug-in card for time-correlated single-photon counting (TCSPC). The time-resolved fluorescence signals were analyzed and identified by a maximum likelihood estimator (MLE). The x,y-microscope scanning stage allows for discontinuous, bidirectional scanning of up to 16 capillaries in an array, resulting in longer fluorescence collection times per capillary compared to scanners working in a continuous mode. Synchronization of the alignment and measurement process were developed to allow for data acquisition without overhead. Detection limits in the subzeptomol range for different dye molecules separated in parallel capillaries have been achieved. In addition, we report on parallel time-resolved detection and separation of more than 400 bases of single base extension DNA fragments in capillary array electrophoresis. Using only semiconductor technology the presented technique represents a low-cost alternative for high throughput DNA sequencing in parallel capillaries. 相似文献
75.
The oxygen chemisorption on Ni, Cu and Ag is studied by comparing PE spectra of these systems and SCF-Xα scattered-wave cluster models. Consideration of octahedral clusters M6 (M = Ni, Cu, Ag) shows that they are large enough to reproduce trends in energy differences, such as the width of the d-bands and the distance from the top of the d-bands to the Fermi level, as found in experiment and in bulk energy band calculations. Substrate model clusters for the interaction of oxygen with different metal surfaces are derived from an octahedron by removing one ((100) face) or two adjacent metal atoms ((110) face). Comparing the UPS difference spectrum for O/Ag (110) with several Ag4O cluster models makes it possible to interpret the peaks above the Ag d-band as O-Ag anti-bonding levels. These peaks are caused by O 2p-Ag 4d and O 2p-Ag 5s interaction. The corresponding bonding levels fall in the Ag d-bands and cannot therefore be identified with confidence in the spectra. The decreasing intensity of the oxygen derived peak below the metal d-band in the UPS spectra when going from Ni to Cu to Ag, and the simultaneously increasing O peaks above the d-band correlate with the changes of the localization of the corresponding bonding and anti-bonding levels in the oxygen sphere and the decreasing strength of the chemisorption bond. 相似文献
76.
Soliton physics has made considerable progress in solving nonlinear problems. This paper is meant to relate the soliten concept to the stationary axisymmetric vacuum fields in general relativity. We present a functional transformation which, working as a nonlinear creation operator, generates gravitational fields of isolated sources. When applied to flat space-time (gravitational vacuum) this operation leads to a nonlinear superposition of an arbitrary number of Kerr particles. This superposition also includes the Tomimatsu-Sato fields. The functional transformations form an infinite-parameter group which contains the Kinnersley-Geroch group as a subgroup.This essay received the second award from the Gravity Research Foundation for the year 1980.-Ed. 相似文献
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80.
Dietrich Gudat Martin Schrott 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Examples for 2-D shift correlations between 31P and another heteronucleus via nX-detected 2D-INJZPT or 31P-detected HMQC experiments are presented. The former technique is best suited for 31P, 15N correlations and permits the determination of intramolecular connectivities as well as of relative signs of couplings.1 The “inverse” HMQC expenment allows easy recording of the 77Se NMR spectrum of an equilibrium mixture of 2 and 33, disregarding the severe exchange broadening of the 77Se-resonances 相似文献