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  • 1
    ISSN: 0947-6539
    Keywords: ab initio calculations ; carboranes ; electron diffraction ; rearrangements ; structure elucidation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: closo-1,2-(SiMe3)2-1,2-C2B4H4 undergoes thermal conversion to 1,6-(SiMe3)2-1,6-C2B4H4. The reaction pathway was monitored by 11B NMR spectroscopy. The structures of the 1,2- and 1,6-isomers were optimized at the HF/6-31 G* ab initio level. Gas-phase electron diffraction studies for both isomers are reported, as well as low-temperature X-ray crystal structure determinations. Comparison of calculated structural data with the data obtained experimentally shows good agreement between theory and experiment.
    Additional Material: 6 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3781-3804 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Perhalogenated 1,2,3,5-Dithiadiazolium Salts and 1,2,3,5-DithiadiazolesSyntheses of the perhalogenated 1,2,3,5-dithiadiazolium salts FCN2S2+Cl- (5) (by methathesis from ClCN2S2+Cl- with AgF2), FCN2S2+AsF6- (5a) (from 5 and AgAsF6), CF3CN2S2+Cl (11) (from CF3CN and S3N3Cl3 in liquid SO2 (in this reaction the by-products S5N5+Cl4- (9), S4N4O2 (10), CF3CN3S2Cl2 (11a), and CF3CN4S3+S3N3O4- (12) are isolated, too), and BrCN2S2+Cl- (15) (from 13c and SO2Cl2) are reported. By reduction of XCN2S2+ (Cl, Br)- with Zn in liquid SO2 the corresponding radicals XCN2S2· (13a - d, X = F, Cl, Br, CF3) are formed in high yields. These radicals are diamagnetic in the solid state. From 13b and d and their corresponding chlorides distinct compounds of the composition (XCN2S2)3Cl (16a, b, X = Cl, CF3) are obtained, while in the reaction of 13b with ClCN2S2+SbCl6 only reduction of the anion under formation of (ClCN2S2+)2SbCl52- (17) occurs. Structures of 13d and 16b were determined by X-ray-, of 13d also by electron-diffraction in the vapour phase. In order to understand the observed structures and ESR spectra of 13, model calculations by the MNDO method were performed for the RCN2S2-system and also for possible dimers there of.
    Notes: Synthesen der perhalogenierten 1,2,3,5-Dithiadiazolium-Salze FCN2S2+Cl- (5) (durch Metathese aus ClCN2S2+Cl- mit AgF2), FCN2S2+AsF6- (5a) (aus 5 und AgAsF6), CF3CN2S2+Cl- (11) (aus CF3CN und S3N3Cl3 in fl. SO2 (bei dieser Reaktion werden als Nebenprodukte u.a. S5N5+FeCl4- (9), S4N4O2 (10), CF3CN3S2Cl2 (11a) und CF3CN4S3+S3N3O4- (12) isoliert) und BrCN2S2+Cl- (15) (aus 13c und SO2Cl2) werden mitgeteilt. Durch Reduktion von XCN2S2+(Cl, Br)- mit Zn in fl. SO2 entstehen die entsprechenden Radikale XCN2S2· (13a-d, X = F, Cl, Br, CF3) in hohen Ausbeuten. Diese Radikale sind im festen Zustand diamagnetisch. Durch Umsetzung von 13b und d mit den ihnen zugrunde liegenden Chloriden lassen sich definierte Verbindungen der Zusammensetzung (XCN2S2)3Cl (16a, b, X = Cl, CF3) erhalten. Bei der Umsetzung von ClCN2S2+SbCl6- mit 13b erfolgt dagegen Reduktion des Anions unter Bildung von (ClCN2S2+)2 SbCl52- (17). Die Strukturen von 13d und 16b wurden durch Röntgen-, die von 13d außerdem durch Elektronenbeugung in der Gasphase bestimmt. Zum Verständnis der gefundenen Strukturen und der gemessenen ESR-Spektren von 13 wurden Modellrechnungen nach der MNDO-Methode an dem RCN2S2-System sowie an den möglichen Dimeren von 13 durchgeführt.
    Additional Material: 8 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2117-2122 
    ISSN: 0009-2940
    Keywords: 1λ4,3λ4,5λ4-Trithiatriazines ; Anomeric effect ; Antiaromaticity ; Calculations, ab initio, MNDO ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Structure of TrithiatriazinesMNDO and ab initio calculations have shown that the structure of trithiatriazines [(RSN)3, where R = F, Cl, {H}] is influenced by the anomeric effect and by antiaromaticity of the ring for electron pairs in axial positions. These calculations are supported by a joint electron diffraction and microwave structure determination of (NSF)3 in the gas phase.
    Additional Material: 2 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2123-2127 
    ISSN: 0009-2940
    Keywords: 1λ4,3λ4-Dithiatriazines ; Calculations, MNDO ; Anomeric effect ; Electron diffraction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Anomeric Effect in DithiatriazinesFrom (CF3CN3S2)n (1) and XeF2, Br2, or (CF3)2NO* the corresponding S,S-substituted dithiatriazines CF3CN3S2F2 (2), CF3CN3S2Br2 (3), and CF3CN3S2[ON(CF3)2]2 (4) are prepared. An electron diffraction study of 2 in the gas phase results in a slightly aplanar 6-membered ring with chair conformation and both S-F bonds in axial position. MNDO calculations show that the position of the substituents at the sulfur atoms is strongly dependent on these substituents and on the ring geometry. The cis preference is the result of an anomeric effect.
    Additional Material: 3 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 665-668 
    ISSN: 0009-2940
    Keywords: 2-Isotetrasilanylsodium salt ; Trisilylgermyl(alkali metal) salt ; 2-Methylisotetrasilane ; Methyltrisilylgermane ; Electron diffraction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Molecular Structure of CH3M(SiH3)3 (M=Si, Ge)A solution of 2-isotetrasilanylsodium (1a) was obtained in good yield from silane and sodium under special conditions. Methylation of 1a with methyl p1-toluenesulfonate yields 2-methylisotetrasilane (1b). The corresponding methyltrisilylgermane (2b) was synthesized via (K, Cs)Ge(SiH3)3 (2a) resulting from the reaction of cesium trichlorogermanide with KSiH3 followed by methylation. The molecular structures of 1a and 1b were determined by electron diffraction analyses.
    Additional Material: 3 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1347-1352 
    ISSN: 0009-2940
    Keywords: 1α4,2,4,6-Thiatriazines, preparation, structures ; 1α4,2,4,6-Thiatriazinium cations ; Calculations, MNDO ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: FluorothiatriazinesFrom the reaction of (ClCN)2(ClSN) (1) with AgAsF6 in liquid SO2 (ClCN)2(SN)⊕ AsF⊖06 (2) is obtained in quantitative yield. With CsF 2 gives (ClCN)2(FSN) (3), which slowly dismutates at room temperature to form (ClCN)(FCN)(FSN) (4) and 1. Fluorination of 1 with SbF3 yields (FCN)2(FSN) (5). With AsF5 5 forms the salt (FCN)2(SN)⊕ AsF⊖ (6). The cation of 6 is transformed by NOCl or CsBr into the corresponding neutral derivatives (FCN)2(ClSN) (7) and (FCN)2(BrSN) (8), respectively. The gas-phase structure of 5 was determined by electron diffraction. The influence of the different exocyclic substituents on the bond properties in this ring system is explained by means of MNDO calculations.
    Additional Material: 2 Ill.
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  • 7
    ISSN: 0009-2940
    Keywords: Ethaneselenol, pentafluoro-, IR, Raman, NMR, electron diffraction ; ab initio Calculation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactive E=C(p-p)π Systems, XXXVII[1]. - Pentafluoroethaneselenol: Synthesis, Spectra, and Gas-Phase StructureHerrn Professor Wolfgang Sawodny zum 60. Geburtstag gewidmet.Pentafluoroethaneselenol HSeC2F5 (1) and its deuterated analogue DSeC2F5 (2) are obtained in moderate yields by cleavage of the diselane (SeC2F5)2 with Me3SnH and Me3SnD, respectively. Complete characterization of the labile compounds was accomplished by spectroscopic investigations (IR, Raman, MS; 1H, 13C, 19F, 77Se NMR). The molecular structure was determined by electron diffraction in the gas phase together with ab initio calculations.
    Additional Material: 3 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 461-464 
    ISSN: 0009-2940
    Keywords: Bis(trifluoromethylthio)methane ; Gas-phase structure ; Conformational properties ; Electron diffraction ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The geometric structure and conformational properties of bis(trifluoromethylthio)methane, CH2(SCF3)2' were determined by gas electron diffraction. The main conformer (70 ± 15%) possesses C2 symmetry with dihedral angles Φ(SCSC) = 79.1(10)°. The second conformer possesses C1 symmetry. The following skeletal geometric parameters (distances ra [pm] and angles 〈α[°] with 3-σ uncertainties) were obtained: C—S 183.6(3), S—CF3, 179.3(3), S—C—S 112.1(6), and C—S—C 98.2(10). The geometric structures and relative conformational stabilities were well reproduced by ab initio calculations at the HF/3-21G* level.
    Additional Material: 3 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 131-134 
    ISSN: 0009-2940
    Keywords: Trifluoromethyl vinyl sulfide ; Gas-phase structure ; Electron diffraction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The geometric structure of trifluoromethyl vinyl sulfide, CF3SC(H)=CH2, was determined by gas electron diffraction and ab initio calculations (HF/3-21G* and MP2/6-31G*). A single conformer with a dihedral angle φ(C=C-S-C) = 129(4)° is present. The conformational properties are compared to those of the parent compound, CH3SC(H)=CH2, and of the perfluorinated species CF3SC(F)=CF2.
    Additional Material: 3 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 535-539 
    ISSN: 0009-2940
    Keywords: Dithietanes, fluoro- and fluorooxo-; formation of, cleavage with halogen fluorides, gas phase structure ; Lewis acids, containing fluorine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fluoro- and Fluorooxodithietanes (1) was isolated from the reaction of 2,2,4,4-tetrafluoro-1,3-dithietane (3) with CIF in an unpassivated monelcylinder. The hydrolysis of 1 gives (2): the trans derivative (2b) and the cis isomer (2a) are formed in a 4:1 ratio. (7) is oxidized by CIF at room temperature to give the known (8) in 87% yield. At 50°C from 8 and (9) is formed besides the ring cleavage products CF3SO2CF2SF4Cl (10) and CF3SO2CF2SF5 (11). The gasphase structure of 9 (e.d.) is described. (5) and (13) coordinate by the oxygen of the SO group to AsF5, with an unstable sulfonium salt is formed, while from the reaction of AsF5 and SbF5 with 8 (15 a, b, M = As, Sb) are isolated.
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