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  • 1
    Electronic Resource
    Electronic Resource
    Neutral solvent/crown ether interactions, 4. Crystallization and low temperature (−150°C) structural characterization of 18-crown-6 · 2(CH3CN) (1988)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 6 (1988), S. 65-71 
    Details
    ISSN: 1573-1111
    Keywords: 18-Crown-6 ; C−H acidic hydrogen bonds ; acetonitrile ; low temperature crystal structure ; solvent complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal structure of 18-crown-6 · 2(CH3CN) has been determined via data collection at −150°C. The structure consists of two crown molecules each hydrogen bonded to two acetonitrile moieties in the asymmetric unit, each residing around a center of inversion. The crown ethers display their fullD 3d symmetry; methyl ... O contacts range from 3.189(8) to 3.598(8) Å. There are no close contacts indicative of any interaction between the crown/2(CH3CN) units.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00659370
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  • 2
    Electronic Resource
    Electronic Resource
    f-Element/crown ether complexes: 21. Conformational changes in metal complexed versus hydrogen bonded benzo-15-crown-5 in the structure of [Y(OH2)3(NCMe)-(benzo-15-crown-5)][ClO4]3·benzo-15-crown-5·CH3CN (1989)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 7 (1989), S. 277-287 
    Details
    ISSN: 1573-1111
    Keywords: Benzo-15-crown-5 ; yttrium perchlorate ; low temperature crystal structure ; hydrogen bonding ; complexation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Crystalline [Y(OH2)3(NCMe)(benzo-15-crown-5)][ClO4]3·benzo-15-crown-5-CH3CN can be obtained by slowly cooling a reaction mixture of Y(ClO4)3·n H2O with benzo-15-crown-5 in a solution of acetonitrile and methanol (3 : 1) from 60°C to room temperature. The crystal structure of this complex has been determined at −150 and 20°C. The complex is triclinic,P $$\bar 1$$ . At −150°C the cell parameters area = 11.986(4),b = 12.071(7),c = 16.364(5) Å, α = 93.56(3),β = 98.68(3),γ = 109.68(4)°, vol = 2187 Å3, andD calc = 1.61 g cm−3 forZ = 2 formula units. 3633 independently observed [F o ⩾ 5σ(F o)] reflections were used in the final least-squares refinement leading to an agreement index ofR = 0.048. The Y(III) ion coordination geometry approximates a tricapped trigonal prism with three water molecules and three benzo-15-crown-5 oxygen atoms forming the prism, with the two remaining benzo-15-crown-5 oxygen atoms and the acetonitrile molecule completing the coordination as capping atoms. The three water molecules hydrogen bond a second crown ether molecule and two of the perchlorate anions. The two acetonitrile molecules have contacts with perchlorate oxygen atoms close enough for some weak interaction. One perchlorate is ordered, one is partially disordered as is the coordinated solvent molecule, and the third anion is totally disordered. The two unique crown ether molecules have distinctively different conformations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01076980
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  • 3
    Electronic Resource
    Electronic Resource
    Neutral solvent/crown ether interactions 3. Reorientation of the hydrogen bonds in the low temperature (−150°C) structure of 18-crown-6·2(CH3NO2) (1987)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 5 (1987), S. 631-638 
    Details
    ISSN: 1573-1111
    Keywords: 18-crown-6, nitromethane ; solvent complex ; low temperature crystal structure ; C-H acidic hydrogen bonding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The title complex was crystallized from a saturated solution of 18-crown-6 in nitromethane at 5°C and cooled to −150°C prior to X-ray diffraction data collection. At −150° C 18-crown-6·2(CH3NO2) is monoclinic,P21/n witha=9.290(2),b=7.864(6),c=13.627(8) Å, β=1000.84(4)° andD calc=1.31 g cm−3 for Z=2. Leastsquares refinement using 1521 independent observed reflections [F o≥5σ(F o)] led to a final conventionalR value of 0.041. The complex at −150°C is isostructural with its room temperature structure with the exception of the orientation of the methyl hydrogen atoms and their crown ether oxygen interactions. The methyl group hydrogen atoms were fully refined isotropically. The crown ether resides around a center of inversion and hasD 3d symmetry. There is one methyl hydrogen...crown interaction at 2.35(3) Å, one apparently bifurcated hydrogen bond utilizing a second methyl hydrogen atom (2.55(3), 2.65(3) Å) and the third hydrogen atom is actually directed away from the crown ring (closest H...O contact=2.67(3) Å).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00663004
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  • 4
    Electronic Resource
    Electronic Resource
    f-Element/crown ether complexes, 11. Preparation and structural characterization of [UO2(OH2)5] [ClO4]2·3(15-crown-5)·CH3CN and [UO2(OH2)5] [ClO4]2·2(18-crown-6)·2 CH3CN·H2O (1987)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 5 (1987), S. 645-658 
    Details
    ISSN: 1573-1111
    Keywords: 15-crown-5 ; 18-crown-6 ; hydrogen bonding ; uranyl perchlorate ; low temperature crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The reaction of UO2(ClO4)·nH2O with 15-crown-5 and 18-crown-6 in acetonitrile yielded the title complexes. [UO2(OH2)5] [ClO4]2·3(15-crown-5)·CH3CN crystallizes in the triclinic space groupPT with (at−150°C)a=8.288(6),b=12.874(7),c=24.678(7) Å, α=82.62(4), β=76.06(5), γ=81.06(5)°, andD calc=1.67 g cm−3 forZ=2 formula units. Least-squares refinement using 6248 independent observed reflections [F o≥5σ(F o)] led toR=0.111. [UO2(OH2)5] [ClO4]2·2(18-crown-6)·2CH3CN·H2O is orthorhombicP212121 with (at−150 °C)a=12.280(2),b=17.311(7),c=22.056(3) Å,D calc=1.68 g cm−3,Z=4, andR=0.032 (3777 observed reflections). In each complex the crown ether molecules are hydrogen bonded to the water molecules of the pentagonal bipyramidal [UO2(OH2)5]2+ ions, each crown ether having exclusive use of two hydrogen atoms from one water molecule and one hydrogen from another water molecule. In the 15-crown-5 complex the remaining hydrogen bonding interaction is between one of the water molecules and one of the perchlorate anions. The solvent molecule has a close contact between the methyl group and a perchlorate anion suggesting a weak interaction. There are a total of three U-OH...OClO3 hydrogen bonds to the two perchlorate anions in [UO2(OH2)5] [ClO4]2·(18-crown-6)·2CH3CN ·H2O. The remaining coordinated water hydrogen bond is to the uncoordinated 2H2O molecule, which in turn is hydrogen bonded to a perchlorate oxygen atom and an acetonitrile nitrogen atom. One solvent methyl group interacts with an anion, the other with one of the 18-crown-6 molecules. Unlike the 15-crown-5 structure, the hydrogen bonding in this complex results in a polymeric network with formula units joined by hydrogen bonds from one of the solvent molecules and the uncoordinated water molecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00663006
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  • 5
    Electronic Resource
    Electronic Resource
    Neutral molecule/crown ether interactions 5. Comparison of the C−H acidic interactions of nitromethane and acetonitrile with 18-crown-6 and dibenzo-18-crown-6. Crystal structures of dibenzo-18-crown-6·2 CH3NO2 and dibenzo-18-crown-6·2 CH3CN (1988)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 6 (1988), S. 629-645 
    Details
    ISSN: 1573-1111
    Keywords: Dibenzo-18-crown-6 ; acetonitrile ; nitromethane ; solvent complex ; low temperature crystal structure ; C−H acidic hydrogen interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Complete structural characterization of dibenzo-18-crown-6·2 CH3NO2 and dibenzo-18-crown-6·2 CH3CN have been carried out, including location and refinement of the methyl hydrogen atoms. Dibenzo-18-crown-6·2 CH3NO2 is monoclinic,P21/c, with (at −150°C)a=9.573(2),b=14.636(2),c=33.471(7) Å, β=93.77(2)°, andD calc=1.37 g cm−3 forZ=8. Interactions between the solvent methyl groups and the crown ethers and other solvent nitro groups associate the 1 : 2 complexes into polymeric chains alongb. The acetonitrile adduct exists as discreet 1 : 2 complexes in the solid state with C−H...O interactions exlusively to the ether. This complex is triclinic,P 1, with (at −150°C)a=9.458(6),b=9.570(5),c=14.404(5) Å, α=73.18(4), β=79.85(5), γ=66.82(6)°, andD calc=1.28 g cm−3 forZ=2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656345
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