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  • 1995-1999
  • 1985-1989  (8)
  • 1890-1899
  • 1985  (8)
  • crystal structure
  • 1
    Electronic Resource
    Electronic Resource
    On the physical crosslinking of amine-extended polyurethane urea elastomers: A crystallographic analysis of bis-urea from diphenyl methane-4-isocyanate and 1,4-butane diamine (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 335-341 
    Details
    ISSN: 1435-1536
    Keywords: Polyurethane elastomers ; hard segment ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The substance under investigation is taken as a model for hard segments consisting of MDI 1) and 1,4-butane diamine. It crystallizes in the triclinic space group P¯1 witha=4.6297;b=5.8259;c=25.286 Å;α=90.721;β=91.580;γ=102.90 degrees andZ=1. Bond distances and angles are given, together with some data on the conformation. The most significant finding is that neighbouring molecules in one and the same plane are linked to one another by means of bifurcated hydrogen bonds. A comparison with the corresponding data for an analogous bis-urethane provides a plausible explanation of the main differences between diamine and glycol extension in polyurethane elastomers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01412250
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  • 2
    Electronic Resource
    Electronic Resource
    On the structures of X- and Y-type zeolites. Structural changes within the cavities of Na-Y during dehydration and contrasts with Na-X systems (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 143-149 
    Details
    ISSN: 1573-1111
    Keywords: Zeolite Y ; zeolite X ; crystal structure ; faujasite ; dehydration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Samples of dehydrated and partially dehydrated Na-Y were examined by X-ray diffraction methods revealing the progressive structural changes which occur as water is removed and the different behaviour compared with Na-X. The differences between Na-Y and Na-X reflect the reduced Al content of Na-Y and the consequential lower average capability of each framework oxygen atom for balancing cation charges. In the small-pore region of Na-Y, the total number of Na atoms remains relatively constant during dehydration (ca. 15 per unit cell compared withca. 18 in Na-X); unlike Na-X, Na-Y, has no site I atoms. Significant dehydration of the small-pore region, and the change from low to high site II occupancy, do not occur until the total water content of the sample is less than that which pertains under atmospheric conditions. In the 12-ring regionn of Na-Y, [Na(H2O)2]+ units are observed at an intermediate level of dehydration, possibly linked by water molecules astride the site III region to networks in adjacent 12-rings. There is no build-up, as in Na-X, of Na at site III, and site IIB (=III′) is (at least partially) occupied by H2O rather than Na. Further dehydration progressively removes H2O but there is little rearrangement of Na atom positions, except the build-up in site II which accounts for much of the loss of Na from the mobile phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687987
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  • 3
    Electronic Resource
    Electronic Resource
    The interaction of alkali metal cations with aromatic molecules in complexes of the type M[AlMe3X]·aromatic, M[Al2Me6X]·aromatic, and related (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 13-20 
    Details
    ISSN: 1573-1111
    Keywords: alkali metal ions ; metal-aromatic interactions ; crystal structure ; aluminum alkyls
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal structures of 13 compounds of the form M[Al2Me6X]·aromatic and related have been examined in order to learn about the M+...aromatic approach. Four types of interactions have been discerned: (1) metal...aromatic, (2) metal...aromatic...metal, (3) aromatic...metal...aromatic, and (4) no metal...aromatic contact. It was found that the closest K+...C(aromatic) and Cs+...C(aromatic) separations are essentially equal after a correction for the difference in metal radii. The strength of the K+...aromatic attraction was found to be sufficient to move the K+ ion 0.3 Å out of the plane of the crown ether in two complexes of dibenzo-18-crown-6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00658856
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  • 4
    Electronic Resource
    Electronic Resource
    Behavior of M[Al2Me6N3] (M=K, Rb, Cs) with aromatic solvents and the crystal structures of Cs[Al2Me6N3]·2p-xylene and [K·dibenzo-18-crown-6] [Al2Me6N3]· 1.5(1-methylnaphthalene) (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 113-123 
    Details
    ISSN: 1573-1111
    Keywords: Aromatic...cation interactions ; crown ethers ; liquid clathate ; trimethylaluminum ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The title compounds were synthesized by the addition of AlMe3 to the corresponding azide suspended in an aromatic solvent. Both products were obtained as air-sensitive colorless crystals. Cs[Al2Me6N3]·2p-xylene crystallizes in the monoclinic space groupC2/m witha=19.143(6),b=16.227(6),c=10.392(5) Å, β=114.06(2)o, and ρcalc = 1.20 g cm−3 forZ=4. Refinement led to a conventionalR value of 0.037 for 2179 observed reflections. The cesium atom resides on a mirror plane, and the anion is disordered about a twofold axis. Thep-xylene molecules sandwich the cesium ion. [K·dibenzo-18-crown-6] [AlMe6N3]·1.5(1-methylnaphthalene) crystallizes in the monoclinic space groupP21/c witha=14.176(5),b=13.021(5),c=25.324(8) Å, β=98.23(4)0, and ρcalc = 1.08 g cm−3 forZ=4. The finalR value was 0.132 for 1402 observed reflections. One of the 1-methylnaphthalene molecules is disordered about a center of inversion and interacts with the potassium ion. The other solvent molecule is found roughly in layers in the lattice and also exhibits disorder of the methyl substituent. For both title compounds the AlMe3 groups of the anion exhibit a staggered (C s) conformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687984
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  • 5
    Electronic Resource
    Electronic Resource
    Interaction of dihydroxy host systems with glycols. A comparative study of the crystal structures of 1:1 molecular complexes of 1,4-butanediol with 2,5-bis(4-chlorophenyl)hydroquinone andtrans-9,10-dihydroxy-9,10-diphenyl-9,10-dihydroanthracene (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 225-233 
    Details
    ISSN: 1573-1111
    Keywords: crystal structure ; hydroquinone ; p-terphenyl ; dihydroanthracene ; hydrogen bonding ; host-guest compound ; molecular complex ; adduct
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The title compounds crystallize in space groupC2/c withZ=4; C18H12O2Cl2·HO(CH2)4OH,a=16.186(3),b=7.626(1),c=16.939(3) Å, β=91.32(2)°,R F =0.048 for 1743 observed MoKα reflections; C26H20O2·HO(CH2)4OH,a=11.881(3),b=13.009(4),c=16.689(4) Å, β=110.67(2)°,R F =0.066 for 1783 data points. Both structures feature centrosymmetric hydrogen-bonded (OH)4 rings formed by molecular components located in special positions. Different packing modes account for the observed conformations (g + ag − andaaa, respectively) of 1,4-butanediol and its possible replacement by 1,2-ethanediol as a guest in the former crystal structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655726
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  • 6
    Electronic Resource
    Electronic Resource
    Reaction of trimethylaluminum with crown ethers. III. The synthesis and crystal structure of (12-crown-4)bis(trimethylaluminum) (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 65-69 
    Details
    ISSN: 1573-1111
    Keywords: crown ether ; trimethylaluminum ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crown ether 12-crown-4 reacts with trimethylaluminum in toluene to form the complex [AlMe3]2[12-crown-4]. Attempts to utilize the remaining two oxygen atoms for coordination to AlMe3 molecules were unsuccessful. The 2∶1 complex crystallizes in the monoclinic space groupP21/n witha=11.342(7),b=12.941(4),c=6.973(6) Å, and β=95.48(4)°. Refinement led to a finalR value of 0.047 for 925 observed reflections. The molecule resides on a crystallographic center of inversion, and as required by symmetry, the four oxygen atoms are planar. The Al−O bond is strong as revealed by the bond length of 1.977(3) Å.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00658863
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  • 7
    Electronic Resource
    Electronic Resource
    On the structures of X- and Y-type zeolites. Structural changes within the cavities of Na-X during dehydration (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 135-142 
    Details
    ISSN: 1573-1111
    Keywords: Zeolite X ; crystal structure ; faujasite ; dehydration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Samples of partially dehydrated and dehydrated Na-X were examined structurally by X-ray diffraction methods, revealing the progressive structural changes which occur as water is removed. In general, the total number of Na atoms in the small pore region remains unchanged by dehydration (ca. 18 per unit cell), as does the total number (non-mobile) in the 12-ring and site III regions (ca. 39). The site II population, however, is more than doubled by dehydration, from about 12 to about 25 Na, accounting for most of the loss from the mobile phase. The 12-ring sites, which in hydrated samples appear to comprise pairs of centrosymmetrically related [Na(H2O)2]+ units, rearrange during dehydration, with site III becoming an important location of Na atoms. At intermediate levels of dehydration, the remaining localized water molecules in the 12-ring region are found in a variety of associations with Na atoms, including perhaps as [Na(H2O)5]+ units whose Na atom occupies site III. In a sample containing H3O+ ions as well as Na+ as counter ions, site II was found to have a very low occupancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687986
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  • 8
    Electronic Resource
    Electronic Resource
    The polyiodide salts: Pyridinium pentaiodide;β-naphthylammonium pentaiodide; andN-methyl-γ-picolinium heptaiodide. Structures with channel inclusion features (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 173-182 
    Details
    ISSN: 1573-1111
    Keywords: Polyiodide salts ; pyridinium pentaiodide ; β-naphthylammonium pentaiodide ; N-methyl-γ-picolinium heptaiodide ; channel inclusion arrangement ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal structures of three polyiodode salts are reported (pyridinium pentaiodide, monoclinic,P2 1/m,a=9.221(5),b=12.918(5),c=6.026(4) Å, β=103.60(7)o,Z=2,R F=0.087 for 1187 intensities; β-naphthyl-ammonium pentaiodide, triclinic,173-1,a=10.390(5),b=9.502(5),c=4.462(3) Å, α=99.19(7), β=90.40(7),γ=108.49(8)o,Z=2,R F=0.059 for 1319 intensities;N-methyl-γ-picolinium heptaiodide, monoclinic,C2/c,a=19.315(7),b=12.714(5),c=8.442(4) Å, β=107.26(7)o,Z=4,R F=0.065 for 1336 intensities). All three structures can be described as having channel inclusion features; the cations are contained in channels in polyiodide frameworks based on different arrangements of I2 molecules and I 3 − anions. This structural type is the converse of the more widespread kind where polyiodide anions are contained in an organic matrix (e.g., cyclodextrin polyiodides).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687991
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