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  • Inorganic Chemistry  (5)
  • Wiley-Blackwell  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1087-1092 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Hydrazine and its Derivatives, XLVIII. 2-Amino-1,3-dithia-2-aza-1,1,3,3-cyclohexanetetroneBy the reaction of 1,3-propanedisulfonyl dichloride with hydrazine dihydrochloride and sodium hydroxide the 1,1-disubstituted hydrazine 1b is formed. The preparation of the isomeric compound 1a analogous to the cyclic dicarboxylic acid hydrazides did not succeed. 1b forms with acetic acid the derivative 4 and with benzaldehyde the hydrazone 5. The structure of 1b was determined by X-ray analysis and discussed by means of the data thus obtained.
    Notes: Bei der Umsetzung von 1,3-Propandisulfonyl-dichlorid mit Hydrazinium(2+)-dichlorid und Natronlauge entsteht das 1,1-disubstituierte Hydrazin 1b. Die Darstellung der isomeren Verbindung 1a in Analogie zu den cyclischen Dicarbonsäurehydraziden gelang nicht. 1b bildet mit Eisessig das Derivat 4 und mit Benzaldehyd das Hydrazon 5. Die Struktur von 1b wurde durch Röntgenanalyse bestimmt und anhand der erhaltenen Daten diskutiert.
    Additional Material: 1 Tab.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 2684-2690 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Hydrazine and its Derivatives, LI1 Crystal and Molecular structure of N, N, N′, N′-Tetraaminopiperazindiium Bis(azide)The structure of the title compound 3 was determined by X-Ray analysis. The compound crystallizes in the monoclinic space group P21/c. The six-membered heterocycle of the dication exists in chair conformation. Bond lengths, bond angles, and dihedral angles of this first triazanium salt investigated by X-ray diffraction as well as the NH2… N3 hydrogen bonds in the crystal are discussed.
    Notes: Die Struktur der Titelverbindung 3 wurde durch eine Röntgenanalyse bestimmt. Die Verbindung kristallisiert in der monoklinen Raumgruppe P21/c. Der sechsgliedrige Heterocyclus des Dikations liegt in der Sesselkonformation vor. Bindungslängen, Bindungswinkel und Torsionswinkel dieses ersten röntgenographisch untersuchten Triazanium-Salzes sowie im Kristall auftretende NH2…N3-Wasserstoffbrücken werden diskutiert.
    Additional Material: 4 Ill.
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  • 3
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,2,3,4-[1′,8′]Anthra-8,9;10,11-dibenzo[13]annulen und 1,8-Distyrylanthracen als Modelle für Phenylenvinylen-Systeme. Synthesen, Strukturen und RedoxeigenschaftenDie Synthesen der formal als [13]Perimeter aufzufassenden Titelverbindungen 4 und ihres acyclischen Modellsystems 1,8-Distyrylanthracen (6) werden beschrieben. Die Kristallstruktur von 4 zeigt die Konfiguration der Doppelbindungen und die Konformation des Makrocyclus auf. Entsprechende Befunde ergeben sich aus den 1H-NMR-Spektren von 4 und 6 in Lösung. Die Spindichteverteilung in den Radikalanionen 4-· und 6-· wird im Hinblick auf die Art des einfach besetzten Molekülorbitals und auf die Molekülgeometrie diskutiert. Verbindung 6 erweist sich als effizienter Elektronenakzeptor, denn es kann zu einem Tetraanionsalz reduziert werden. Die komplette Redoxsequenz wird mit Hilfe der NMR- und ESR-Spektroskopie charakterisiert.
    Notes: The synthesis of the title compound 4, formally a [13] perimeter, and of its acyclic model system, 1,8-distyrylanthracene (6) is described. The crystal structure of 4 reveals the configuration of the double bonds and the conformation of the macrocycle. Related findings come from the 1H-NMR spectroscopic characterization of 4 and 6 in solution. The spin density distribution of the radical anions 4-· and 6-· is interpretet in terms of the singly occupied molecular orbital and of the prevailing geometry. In contrast to 4, compund 6 proves to be an efficient electron acceptor since it can even be reduced to a tetraanion salt. The complete redox sequence is characterized by NMR and ESR spectroscopy.
    Additional Material: 4 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2349-2371 
    ISSN: 0009-2940
    Keywords: Atropisomers ; Inversion barrier ; Lineshape analysis ; Calculations, force field ; Resonance energy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Inversion Barriers of ortho,ortho′-Bridged BiphenylsThe syntheses and spectroscopic properties of the ortho,ortho′-bridged biphenyls 2-19 are described. In the case of 5, 15, and 16 the inversion barrier is determined from the temperature dependence of the NMR spectra (lineshape analysis), in the case of 12, 13, and 14 from the temperature of coalescence, and in the case of 2a, 3b, 7, 17, 18, and 19 from the rate of racemization of the optically active compounds. The experimental inversion barriers, including data from the literature, are compared with those calculated using the extended force field (MM2erw). The conformational behavior of the title systems is significantly affected upon transformation into the corresponding dianion salts. The relevant energy terms are discussed.
    Additional Material: 5 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2819-2831 
    ISSN: 0009-2940
    Keywords: Alkylation, reductive ; Cycloannulation, regio- and stereoselective ; Calculations, MMPMI ; Valence isomerizations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reductive Transformations, 18[2]. - Cycloannulation and Bridging of Cyclooctatetraene[1]Reductive alkylations of cyclooctatetraene (1) with biselectrophiles have hitherto been described as proceeding solely under 1,2-cycloannulation. Using different alkylating agents with varying chain lengths, conformational mobility, and leaving groups we succeeded in achieving regio- and stereoselective reactions of the intermediate monoalkyl monoanion 3. By systematic variation of the biselectrophiles the subtle competition of 1,2- versus 1,4- and of 1,n-cis- versus 1,n-trans-cyclization is elucidated. It is shown that the regio- and stereoselectivity are controlled mainly by the structure of the alkylating reagents while other parameters such as solvent or leaving group do not play an important role. Reductive alkylation of 1 provides an easy access to a large number of compounds which may be oxidized to new cyclooctatetraene systems or serve as substrates for further skeletal rearrangements. - X- ray structure analyses are performed for compounds 15, 27 a, 28, and 29.
    Additional Material: 12 Tab.
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