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  • 1
    ISSN: 1434-4475
    Keywords: Azide ; Cesium ; Crystal structure ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The crystal structure of dicesium-tetraazido-zincate, Cs2Zn(N3)4, has been refined from single crystal X-ray-diffractometer data. The previously reported orthorhombic structure, consisting of isolated Zn(N3)4-tetrahedra was confirmed and improved lattice parameters and atomic distances were determined. The azide groups are asymmetric and the coordination of central nitrogen atoms to cesium was observed. A table of structure data and mean atomic distances for fourteen zinc-azide compounds is added and the structures are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 123 (1992), S. 325-331 
    ISSN: 1434-4475
    Keywords: Azide ; Crystal structure ; Dimethylpyridine ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Three adducts of zinc azide with 2,4-/3,4- and 3,5-dimethylpyridine (DMP), respectively, were prepared and the crystal structures determined by single crystal X-ray diffraction methods. The three compounds crystallize in the monoclinic space group P21/c withZ=4: Zn(N3)2·2,4-DMP at 300 (2) K:a=1 098.6(4),b=1 600.2(6),c=608.8(3) pm, β=102.47(3)°;R=0.071 (R w =0.056). Zn(N3)2·3,4-DMP at 103 (3) K:a=1 102.1(3),b=1 649.0(4),c=611.8(1) pm, β=104.54(2)°;R=0.055 (R w =0.051). Zn(N3)2·3,5-DMP at 97 (3) K:a=602.1(2),b=2 037.9(7),c=853.8(3) pm, β=90.77(3)°;R=0.069 (R w =0.055). The molecular geometry is similar for the three adducts, but the packing of theDMP-molecules is different. The zinc atoms are surrounded by five nitrogen atoms, four belonging to the azide groups and one to theDMP-adduct. The trigonal bipyramidal shaped ZnN5-polyhedra share common edges to form chains.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 98 (1965), S. 844-850 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch ESR-Spektren und optische Spektren läßt sich die Dissoziation von Tetrakis-[p-methoxy-phenyl]-hydrazin und Tetrakis-[p-dimethylamino-phenyl]-hydrazin bei Raumtemperatur und von Tetrakis-p-tolyl-hydrazin bei erhöhter Temperatur in die entsprechenden Diarylstickstoff-Radikale feststellen. Dagegen konnte eine Dissoziation von Tetraphenyl-, Tetrakis-[p-fluor-phenyl]- und Tetrakis-[p-brom-phenyl]-hydrazin bis 90° weder mit der Elektronenresonanz noch im optischen Spektrum nachgewiesen werden.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 523-533 
    ISSN: 0009-2940
    Keywords: Hofman 1,6-elimination / Pyrazine derivatives / [2.2]Pyrazinophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 1-3 and their methyl derivatives 4-7 were synthesized 2,11-dithia[3.3]pyrazinophanes 24-26 or by Hofmann 1,6-elimination of the appropriate [(5-methyl-2-pyrazinyl)methyl]trimethylammonium hydroxides followed by dimerization of the generated 2,5-dihydro-2,5-dimethylenepyrazines. α-Chlorination of the methylpyrazines 8-10 with N-chlorosuccinimide gave the required precursors 11, 12, 14, 17 and 18. The results of the X-ray structure determinations for 1-4 and 7 which indicate an unequivocal isomer assignment are discussed with regard to steric strain in these molecules. The electronic spectra of the pyrazinophanes 7-7 are reported and compared with those of the parent methylpyrazines.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 723-728 
    ISSN: 0009-2940
    Keywords: 1,8-Diaminonaphthalenes, X-ray structure analysis of, conformational barriers of, dynamic behavior of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 2 and 3 have been synthesized from 1,8-diaminonaphthalene. The molecular structure of 2 has been determined by X-ray structure analysis and is discussed with regard to the arrangement of the peri-diphenylamino substituents in the crystalline state and the steric strain in the molecule. NMR studies of 3 reveal two conformational processes. Their nature is discussed and barriers are reported.
    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 123 (1990), S. 1885-1889 
    ISSN: 0009-2940
    Keywords: Pyrimidine derivatives ; Sulfur extrusion, photolytic ; Pyrimidinophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 1 and 2 are synthesized by photolytic sulfur extrusion from the 2,11-dithia[3.3](2,5)pyrimidinophane 17. The molecular structures of 1 and 2 are determined by X-ray structure analysis and are discussed with regard to the steric strain in these molecules. Thermolysis of [(5-methyl-2-pyrimidinyl]methyl]- or [(2-methyl-5-pyrimidinyl)methyl]-trimethylammonium hydroxide (10 or 11) does not generate 1 and 2. α-Chlorination of 2,5-dimethylpyrimidine (3) with N-chlorosuccinimide provides the required precursors 4-6.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 706 (1967), S. 104-106 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch Umsetzung von Malonsäure mit 3 Molen Aryldiazoniumchlorid in Dimethylformamid/Pyridin werden N.N′.C-Triaryl-formazane vom Typ 1 erhalten.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 706 (1967), S. 107-111 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Kupplung von Benzoldiazoniumchlorid mit Trimethylacetaldehyd-phenylhydrazon in Pyridin/DMF ergibt den Bisazokörper 1, der erst durch starke Basen in das Formazan 2 umgelagert wird. Durch Belichten läßt sich 2 nicht in eine offene, gelbe Form überführen. Von 1 und 2 werden dieselben Metallkomplexe erhalten.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Not only strongly basic aromatic amines such as ‘proton sponges’ show characteristic [M - Me2NH - H]+ peaks corresponding to cyclization to stable heterocyclic ions under electron impact. The fragmentation of the title compounds, which are weak bases, leads to [M - RNH2 - C6H5]+ heteroaromatic ions. These are the 7-phenyl-7H-benz[kl]acridine radical cation and the delocalized stable 7H-benz[kl]acridin-7-ylium ion as shown by unimolecular metastable ion spectra, collision-induced decomposition (CID) tandem mass spectrometry (MS/MS) and accurate mass measurements. The high-collision-energy CID tandem mass spectra of these ions are perfectly superimposable on those of the ions produced by the reference substance, 7-phenyl-7H-benz[kl]acridine obtained as a by-product in the Ullmann phenylation of 1,8-diaminonaphthalene. This combination of MS/MS experiments also provides strong support for the gas-phase reaction mechanism leading to the benz[kl]acridine ions and for the structures of these ions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical anions and cations have been prepared by the reduction of the title compounds or their diprotonated derivatives. The same radical ions have been observed by oxidation of the dihydro derivatives. Electron spin resonance hyperfine splitting constants have been assigned on the basis of Hückel and McLachlan calculations and selective substitutions. The hyperfine splitting by the bridging hydrogen atoms in the radical anions was much weaker (0·5 to 0·7 gauss) than for the corresponding radical cations (2 to 3 gauss) for the naphthacene, anthracene, and naphthalene dihydrotetrones. This is interpreted to be a result of orbital symmetry since, in the highest occupied MO for the anion but not for the cation, a nodal plane passes through the bridging hydrogen atom.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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