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  • 1
    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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  • 2
    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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  • 3
    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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  • 4
    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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  • 5
    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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  • 6
    ISSN: 0009-2940
    Keywords: Cyclodisilazanes ; 1,3-Di-tert-butyl-2,2,4,4-tetrafluorocyclodisilazane ; 1,3-Di-tert-butyl-2,2,4,4-tetrachlorocyclodisilazane ; Structure elucidation ; Electron diffraction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The syntheses of 1,3-di-tert-butyl-2,2,4,4-tetrachlorocyclodisilazane (3) and of di-tert-butyl-2,2,4,4-tetrafluorocyclodisilazane (4) are reported. The X-ray crystal structure of 3 and the electron-diffraction gas-phase structure of 4 have been determined. Both cyclodisilazanes possess planar four-membered rings and nearly planar configurations at the nitrogen atoms. The Si-N bond lengths are 171.1(1) pm and 170.6(3) pm and the Si⃛Si transannular distances 245.0(1) and 241.3(13) pm in 3 and 4, respectively.
    Additional Material: 4 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 653-656 
    ISSN: 0009-2940
    Keywords: Hydroxylamine, O-methyl-N,N-bis(trifluoromethyl)-, gas-phase structure of ; Electron diffraction ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular structure of (CF3)2NOCH3 was determined by gas electron diffraction. The molecular intensities were reproduced by use of a single conformation with syn orientation of the O-CH3 group relative to the nitrogen lone pair. This was confirmed by ab initio calculations (HF/3-21G(*), polarization functions only on nitrogen, and MP2/6-31G*). The observed structure demonstrates that the generalized anomeric effect is of minor importance to this compound. The following skeletal geometric parameters (bond lengths [pm] and angles [°] with 3-s̰ uncertainties) were derived: N-C 142.9(7), N-O 142(3), O-C 145(3), CNC 118.0(9), CNO 108.1(17), and NOC 109.4(17). The experimental structure is well reproduced by the 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. 803-805 
    ISSN: 0009-2940
    Keywords: Trifluorotrifiuoromethylthioethene ; Gas-phase structure ; Electron diffraction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular structure of 1-trifluoromethylthio-1,2,2-trifluoroethene, CF3SC(F) = CF2, was determined by gas electron diffraction (GED) and ab initio calculations (HF/3-21G*). The S - CF3 bond is oriented nearly perpendicular to the ethene plane with Φ(C = C-S-C) = 96.9(12)°. This orientation implies that the p-shaped sulfur lone pair is perpendicular to the ethene π orbitals. The following skeletal bond lengths (ra in Å) and angles (χ α in °) were obtained (error limits are 30 values): C = C = 1.302(19) Å, C(sp2) - S = 1.719(9) Å, S—C(sp3) = 1.820(10) Å, C = C—S = 120.0(9)°, and C—S—C = 101.7(7)°. The experimental geometric parameters were reproduced reasonably well by the ab initio method.
    Additional Material: 3 Ill.
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