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  • 1
    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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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 121 (1990), S. 781-786 
    ISSN: 1434-4475
    Keywords: Azide ; Cesium ; Crystal structure ; Europium ; Rare earth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The crystal structure of pentacesium octaazidoeuropiate(III), Cs5Eu(N3)8, was determined by single crystal X-ray diffraction: orthorhombic,a=16.811(4),b=16.860(5),c=16.964(3)Å, space group Pbca,Z=8, 2 310 observed reflections,R=0.048. Europium atoms are coordinated to eight azide groups, the coordination polyhedra have no azide groups in common. Four cesium atoms are surrounded by eight, one by seven azide groups. The azide groups are symmetric with mean N-N-distances of 1.17(1)Å.
    Type of Medium: Electronic Resource
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  • 3
    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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  • 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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