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  • Polymer and Materials Science  (3)
  • Supramolecular chemistry  (1)
  • mannitol derivatives  (1)
  • 1985-1989  (5)
  • 1
    Electronic Resource
    Electronic Resource
    The supramolecular structures and reactivities of some complexes of chiral crown ethers with borane ammonia (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 355-377 
    Details
    ISSN: 1573-1111
    Keywords: Chiral crown ethers ; glycopyranosides ; mannitol derivatives ; borane ammonia complexes ; crystal structures ; enantioselective reductions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Whereas 1 ∶ 1 crystalline complexes have been isolated between borane ammonia and methyl 4,6-O-benzylidene-2,3-dideoxy-α-d-galactopyranosido [2,3-b]-1,4,7,10,13,16-hexaoxacyclo-octadecane (1), methyl 4,6-O-benzylidene-2,3-dideoxy-α-d-mannopyranosido [2,3-b] (methyl 4′,6′-O-benzylidene-2′,3′-dideoxy-α-d-mannopyranosido [2′,3′-k]-1,4,7,10,13,16-hexaoxacyclo-octadecane (3), and (1R,2R,7R,24R)-3,5,8,11,14,17,20,23,26,28-decaoxatricyclo-[21.4.0.02,7]octacosane (4), the hosts, methyl, 4,6-O-benzylidene-2,3-dideoxy-α-d-mannopyranosido[2,3-b] 1,4,7,10,13,16-hexaoxacyclo-octadecane (2) and 1,4 ∶ 1′,4′ ∶ 3,6 ∶ 3′,6′-tetra-anhydro-2,2′ ∶ 5,5′-bis-O-oxydiethylenedi-d-mannitol (5) have yielded 2 ∶ 1 (guest:host) crystalline complexes with borane ammonia as guest. X-ray analyses of the supramolecular structures of BH3NH3 ·1, (BH3NH3)2 ·2, BH3NH3 ·3, BH3NH3 ·4, and (BH3NH3)2 ·5 have been carried out and BH3NH3 ·1, BH3NH3 ·2, and (BH3NH3)2 ·5 have been shown to reduce acetophenone with enantiomeric excesses of 5, 13, and 10% respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655736
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  • 2
    Electronic Resource
    Electronic Resource
    Catalytic activity of benzimidazole in the imidization of polyamic acids (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 36 (1988), S. 243-248 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070360119
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  • 3
    Electronic Resource
    Electronic Resource
    Miscible polybenzimidazole blends with a benzophenone-based polyimide (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 301-313 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Miscible blends of the aromatic polybenzimidazole, poly(2,2(m-phenylene)-5,5′-benzimidazole) (PBI), and the aromatic polyimide formed from 3,3′,4,4′-benzophenone tetracarboxylic dianhydride and 3,3′-diaminobenzophenone (LaRC TPI) have been prepared. Blends with PBI were prepared in N,N-dimethylacetamide solution starting with either the polyamic acid or a 95% imidized form of LaRC TPI; the blend was then precipitated into water or cast as films. The mixture was then imidized thermally to obtain PBI/LaRC TPI blends. Evidence for miscibility was obtained in the form of single composition dependent Tg's intermediate between those of the component polymers and single tan δ dynamic mechanical relaxation peaks. The IR spectra displayed shifts in the N—H stretching band, thereby providing evidence for specific interactions related to the miscibility of these two polymers.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090260208
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  • 4
    Electronic Resource
    Electronic Resource
    Random homogeneous sodium sulfonate polysulfone ionomers: Preparation, characterization, and blend studies (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 25 (1987), S. 1519-1536 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The sodium salts of randomly sulfonated polysulfone (Na-SPSF), derived from 1,1′-sulfonylbis-[4-chlorobenzene] with 4,4′-(1-methylethylidene)-bis-[phenol], were prepared over the composition range of 3-30 mol% sodium sulfonate, using improved procedures in which the sulfonating complex was introduced into an intensely agitated polymer solution. In contrast to earlier work, Tg was found to increase nonlinearly with sodium sulfonate content. A SAXS study provided no evidence of ionic clustering in these polymers. Binary blends of Na-SPSFs differing only in composition were prepared by casting films from solution, and their phase behavior was studied by dynamic mechanical analysis after annealing at 250°C. It was found that the blends were miscible up to a composition difference of about 9-10 mol% sodium sulfonate. Using this fact it was possible to calculate a value for χABn of 200-250, where χAB represents the segmental interaction parameter between unmodified and modified repeat units, and n is the degree of polymerization. Uncertainty in the degree of ionic association places a degree of uncertainty on the effective value of n and therefore on χAB. The product, however, is independent of any assumptions regarding molecular associations.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1987.090250714
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  • 5
    Electronic Resource
    Electronic Resource
    Second-Sphere Coordination-a Novel Rǒle for Molecular Receptors (1986)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 25 (1986), S. 487-507 
    Details
    ISSN: 0570-0833
    Keywords: Second-sphere coordination ; Coordination modes ; Receptors ; Supramolecular chemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Although it has been appreciated for most of this century that the coordinating influence of many transition metal complexes extends beyond their covalently-bonded first-sphere ligands to non-covalently bound chemical species in the so-called second-sphere, it is only recently that the fundamental importance of the phenomenon has been recognized and researched in its most general context. Rapid progress has been possible in this relatively new area of supramolecular chemistry by appealing to the symbiotic relationship that exists between X-ray crystallographic investigations and synthetic work. The gamut of non-covalent bonds, including electrostatic forces, hydrogen bonding, charge transfer, and van der Waals interactions are available for exploitation in choosing or designing suitable molecular receptors for particular transition metal complexes. Crown ethers are the synthetic macrocycles par excellence for forming adducts with neutral and cationic complexes carrying protic ligands (NH3, H2O, CH3CN, etc.) in their first coordination spheres. Anionic complexes with electron-rich first-sphere ligands (e.g. CN⊖) form adducts with polyammonium macrocyclic receptors. In both situations, hydrogen bonds and electrostatic interactions provide the dominant sources of supramolecular stabilization. Spectroscopic studies (UV, IR, and NMR) reveal that the structural integrity of the adducts is usually maintained in solution. The transition metal complexes can be organometallic as well as inorganic. In complexes supporting organic ligands, such as 1,5-cyclooctadiene, norbornadiene, cyclopentadiene, 2,2′-bipyridine, and trimethylphosphane, the opportunity exists to match their steric and electronic characteristics with appropriate binding sites in the molecular receptor. With these ligands, the weaker categories of non-covalent bonding, e.g. charge transfer and van der Waals interactions, assume considerable importance. The phenomenon is also observable with naturally-occurring receptors such as the cyclodextrins and polyether antibiotics. Moreover, it extends beyond the territory of transition metal complexes to main group complexes such as ammonia-borane. As far as applications are concerned, it finds expression in areas as diverse as separation science and drug delivery systems.
    Additional Material: 40 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198604873
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