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  • crystal structure  (3)
  • Guayulin B  (1)
  • Thiophene  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Molecular structures of two conjugated ene-ynes derived from thiophene (1996)
    Springer
    Journal of chemical crystallography 26 (1996), S. 607-613 
    Details
    ISSN: 1572-8854
    Keywords: Thiophene ; conjugated ene-ynes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal structures of two conjugated ene-yne derivatives of thiophene are described, 2,5-di-(trimethylsilylethynyl)-3,4-dibromothiophene (1), is triclinic P $$\bar 1$$ witha=6.3281(4)Å,b=9.7421(6)Å,c=16.3669(9)Å; α=80.516(5)°, β=84.810(5)°, γ=74.072(5)°,Z=2,R=0.054; 2,3,4,5-tetra(trimethylsilylethynyl)thiophene (2), is monoclinic, P21/c with a=20.928(2)Å b=5.852(1)Å,c=23.907(2)Å; β=100.245(6)°,Z=4,R=0.049. The ethynylic C atoms of both compounds lie near the thiophene plane, with deviations in the range 0.010(3)–0.455(4)Å. The phenyl groups of2 form a dihedral angle of 13.0(4)°.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01668621
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Guayulin B (1999)
    Springer
    Journal of chemical crystallography 29 (1999), S. 107-109 
    Details
    ISSN: 1572-8854
    Keywords: Guayulin B ; sesquiterpene ; bicyclogermacradiene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The sesquiterpene guayulin B, C23H30O3, 1, crystallizes with two independent molecules in monoclinic space group P21 with a = 18.099 (1), b = 6.0649(6), c = 19.126(1) Å, β = 100.82(1)°, V = 2062.1(5) Å3, and Z = 4. The double bonds of the cyclodecadiene ring are E, both methyl groups on the 10-membered ring are β-oriented. The cyclopropane ring at C6 and C7 also has the β orientation, while the anisoyloxy group is oriented α. The 10-membered rings of the two independent molecules have the same conformation as that of guayulin A.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009587718394
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Crystal structure of dicyclohexano-18-crown-6 potassium 2-nitrophenoxide (1987)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 5 (1987), S. 379-383 
    Details
    ISSN: 1573-1111
    Keywords: crown ether ; potassium ; crystal structure ; 2-nitrophenoxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The first crystal structure of a potassium cation complex with dicyclohexano-18-crown-6 is reported. The potassium 2-nitrophenoxide complex ofsyn-cis-syn dicyclohexano-18-crown-6 crystallizes in the triclinic space group P $$\bar 1$$ with cell constantsa=8.604(2),b=10.772(4),C=16.123(5)Å, α=73.86(3)°,β=77.61(3)°, γ=82.68(3)° andZ=2 forD c =1.31 g cm−3. Least-squares refinement based on 2742 observed reflections led to a final conventionalR value of 0.040. Dicyclohexano-18-crown-6 has the shape of a saddle with the potassium cation sitting at the saddlepoint. The structure of the 2-nitrophenoxide anion is dominanted by the quinoid resonance contributor. Because the complex is devoid of significant intercomplex interactions, it is a prototypical 1:1:1 complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00665371
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  • 4
    Electronic Resource
    Electronic Resource
    Inclusion of water by a crown amide. First crystal structure of a respective host-guest combination (1988)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 6 (1988), S. 1-7 
    Details
    ISSN: 1573-1111
    Keywords: Crown amide ; host-guest complex ; water inclusion ; crystal structure ; hydrogen bonding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Crown amide (1) forms a stoicheiometric 1:1 inclusion complex with water, the X-ray crystal structure of which is reported. Crystals of1 · H2O are triclinic, space groupP1, witha=7.503(1),b=11.394(3),c=13.443(2) Å, α=107.066(18), β=96.627(10), γ=106.377(14)°, andZ=2.R F =0.039 for 1697 MoKα reflections [I〉3σ(I)] measured at 24°C. The structure features a hydrogen bonded hostguest relationship with concrete1 · H2O units. Hydrogen bonds are between the water oxygen and O(4), N(4), respectively. The crystal packing shows a cavity arrangement of four ligands around each water molecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00659363
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  • 5
    Electronic Resource
    Electronic Resource
    Crystal structure of the 2:1 acetonitrile complex of 18-crown-6 (1988)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 6 (1988), S. 73-78 
    Details
    ISSN: 1573-1111
    Keywords: Crown ether ; acetonitrile ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Single crystal X-ray analysis of the 2:1 acetonitrile complex of 18-crown-6 is reported. Crystals of the complex are monoclinic,P21/n, witha=9.123(3),b=8.524(3),c=13.676(4) Å, β=104.68(3)°, andD c =1.118 g cm−3 forZ=2. The complex lies on a center of symmetry, with the crown in theD 3d conformation. Methyl groups of the acetonitrile molecules have weak interactions with the crown oxygen atoms, and are tilted 31.7° from the host's threefold axis. Methyl hydrogen atoms are rotationally disordered about the acetonitrile axis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00659371
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