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  • 1
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 970-983 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The System Azepine-Benzene imineExtended Hückel calculations are utilized in a discussion of: (a) the equilibrium position of the valence isomerization of 1N-azepine-benzene-1,2-imine, (b) the strenght of the benzeneimine σ bond involved in the isomerization, and (c) the influence of electron accepting groups at the nitrogen atom on the equilibrium position and azepine stability.
    Notes: Mit Hilfe der erweiterten Hückel-Methode werden a) die Gleichgewichtslage der Valenz-isomerisierung 1H-Azepin-Benzol-1,2-imin, b) die Stärke der an dieser Isomerisierung beteiligten σ-Bindung im Benzolimin und c) der Einfluß von Akzeptoren am Stickstoff auf das Gleichgewicht und auf die Stabilität des Azepins diskutiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1795-1813 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A MO Model for the Bimolecular Nucleophilic Substitution on CyclopropanesExtended Hückel calculations are utilized to develop a model for the SN2-reaction on cyclopropanes; according to this model the reaction should occur with retention.
    Notes: Mit Hilfe der erweiterten Hückel-Methode wird ein Modell für die SN2-Reaktion an Cyclopropanen entwickelt, nachdem die Reaktion unter Retention ablaufen sollte.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 8-23 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Stabilisation of the Phenyl CationCalculations of the extended Hückel type are used to discuss the effect of through bond interaction on stabilizing the phenyl cation B and bridgehead ions C.
    Notes: Mit Hilfe der erweiterten Hückel-Methode wird der Effekt der „through bond“ -Wechsel-wirkung zur Stabilisierung des Phenyl-Kations B und einiger am Brückenkopf ionisierter Bicyclen C diskutiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 285-305 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A MO Model for the SN2-Reaction with RetentionQualitative MO-arguments, extended Hückel calculations and ab initio calculations (Gaussian 70) are utilized to develop a MO-model for the SN2-reaction with retention. This model supports a strictly concerted mechanism occuring exclusively with retention. The factors responsible for the SN2-reaction with retention are discussed.
    Notes: Mit Hilfe störungstheoretischer Argumente, der erweiterten Hückel-Methode und ab initio-Berechnungen (Gaussian 70) wird ein MO-Modell für die SN2-Reaktion mit Retention abgeleitet, das einen streng konzertierten Mechanismus mit ausschließlichem Konfigurationserhalt am Substitutionszentrum fordert. Die für die SN2-Reaktion mit Retention notwendigen Voraussetzungen werden diskutiert.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 2708-2721 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Influence of Substituents on sigmatropic Reactions, I. 3-Methylhomotropilidene. Synthesis and EquilibriumAccording to 1H- and 13C n.m.r. spectroscopy 3-methylhomotropilidene (1b) is favored relative to 1-methylhomotropilidene (2b) in the thermal equilibrium. The quantitative interpretation of the 13C-n.m.r. spectra yields ΔH° = 1.6 ± 0.3 kcal/mole, ΔS° = 2.0 ± 0.7 Clausius and ΔG2730 = 1.05 ± 0.05 kcal/mole. EHT-calculations are utilized to understand these results. - The synthesis of the title compound and the unsubstituted homotropilidene 1a is achieved via hydrolysis of the acetals 3 yielding the thermally unstable ketones 4, the treatment of which with diazomethane/CuCl yields 5, which are decarbonylized on heating to the homotropilidenes 1.
    Notes: Im thermischen Gleichgewicht ist das 3-Methylhomotropiliden (1b) gegenüber dem 1-Methyl-homotropiliden (2b) nach Auskunft der 1H-und 13C-NMR-Spektren bevorzugt. Die quantitative Auswertung der 13C-NMR-Spektren liefert ΔH° = 1.6 ± 0.3 kcal/mol, ΔS° = 2.0 ± 0.7 Clausius und ΔG2730 = 1.05 ± 0.05 kcal/mol. EHT-Berechnungen werden zur Deutung dieses Befundes herangezogen. - Die Herstellung der Titelverbindung und des unsubstituierten Grundkörpers 1a erfolgt durch Hydrolyse der Acetale 3 zu den thermolabilen Ketonen 4, die mit Diazomethan/CuCl zu 5 homologisiert werden. Die Thermolyse ergibt die Homotropilidene 1.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    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.
    Type of Medium: Electronic Resource
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  • 9
    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.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 39-45 
    ISSN: 0009-2940
    Keywords: 1,3,2,4,6-Dithiatriazines ; CNS Polycycles, structure determination ; Calculations, MNDO ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of Alkenes to 5-(Trifluoromethyl)-1,3,2,4,6-dithiatriazinesDechlorination of 1,3-dichloro-5-(trifluoromethyl)-1,3,2,4,6-dithiatriazine (1) with Ph3Sb gives (CF3CN3S2)n (2) in quantitative yield. By 1,3-addition of alkenes (dicyclopentadiene, cyclopentene, cis- and trans-2-butene, propene, and ethene) to 2 the corresponding penta- (4a), tri-(5a), and bicyclic ring systems 6a, 6b, 7, 8a, 8b, and 9 are prepared in 65-85% yields. The molecular structures of 6a and 7 were determined by single-crystal X-ray analysis; the other structures were derived from NMR data. The NMR analyses are in accordance with MNDO calculations. For 4a and 5a only the thermodynamically favoured anti-isomers are found, as expected from these calculations; for 6 and 8 they show satisfactory agreement for anti/syn-proportions as determined by NMR spectroscopy. The product distribution corresponds to a symmetry-allowed alkene addition to a singlet dithiatriazine.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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