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  • Polymer and Materials Science  (27)
  • X-ray crystal structure analysis  (5)
  • 1990-1994  (32)
  • 1
    Electronic Resource
    Electronic Resource
    Clathrates of allene dimers. X-ray crystal structures of two inclusion compounds withp-xylene and phenyloxirane (1991)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 10 (1991), S. 267-282 
    Details
    ISSN: 1573-1111
    Keywords: Inclusion compounds ; X-ray crystal structure analysis ; allene dimers ; clathrates ; p-xylene ; phenyloxirane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Allene dimers of the 1,2-dimethylenecyclobutane-type with bridged aromatic groups (fluorenylidene units) and extra substituents (Me,t-Bu)2a-c have been synthesized and characterized by elemental analysis and spectroscopic data. Their crystal inclusion properties are reported. The unsubstituted compound2a yields only an inclusion compound withp-xylene, while methyl-substituted2b enclathrates a broad range of molecules. On the other hand, thet-butyl-substituted2c does not form clathrates, crystallizing as a pure compound. Complete structural descriptions of the two inclusion compounds2a-p-xylene (2:1) and2b-phenyloxirane (1:1) are given. They represent interstitial clathrates. Crystallographic data of the 1:1p-xylene clathrate of2b (which is isomorphous to its phenyloxirane analog) and of unsolvated2c are also reported. As indicated by the results, substitutional effects critically influence the inclusion properties of the new clathrate family.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01066210
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  • 2
    Electronic Resource
    Electronic Resource
    Cyclopropanation of poly[(methylphenylsilanediyl)-(Z)-butenylene]. Synthesis and characterization of poly[(methylphenylsilanediyl)methylenecyclopropylenemethylene] (1990)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 191 (1990), S. 2173-2180 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly[(methylphenylsilanediyl)methylenecyclopropylenemethylene] (3a) was prepared by cyclopropanation of the C—C double bonds of poly[(methylphenylsilanediyl)-(Z)-butenylene] (2a) by a Simmons-Smith reaction. Alternatively, 3a was prepared by a Birch reduction of the dichlorocarbene adduct poly[(methylphenylsilanediyl)methylene(2,2-dichloro-1,3-cyclopropanediyl)-methylene] (4a). Both 3a and 4a show the characteristic absorptions in the 1H, 13C, and 29Si NMR, IR and UV spectra. Their molecular weight distributions, determined by GPC, are rather broad and their thermal stabilities (by TG) are relatively high.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1990.021910918
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  • 3
    Electronic Resource
    Electronic Resource
    Phenyl-2,4,6-trimethylbenzoylphosphinates as water-soluble photoinitiators. Generation and reactivity of O=Ṗ(C6H5)(O-) radical anions (1991)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 192 (1991), S. 2307-2315 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Lithium- and magnesium phenyl-2,4,6-trimethylbenzoylphosphinates (TMPPL and TMPPM) are effective water-soluble photoinitiators for the free-radical polymerization of appropriate monomers such as acrylamide (AA) and methacrylamide (MAA) in aqueous solution. They are also capable of initiating the polymerization of other olefinic compounds such as styrene (St), methyl methacrylate (MMA) or acrylonitrile (AN) in water-containing solvent mixtures such as 1:1 water-acetonitrile mixtures. This is due to the fact that TMPPL and TMPPM undergo α-scission with a rather high quantum yield (φ(α) ≈ 0,35) resulting in the formation of 2,4,6-trimethylbenzoyl radicals and O=Ṗ (C6H5)(O-) radical anions. The latter are very reactive toward olefinic monomers. Bimolecular rate constants kR+M/(L/(mol · s)) were determined by flash photolysis at room temperature, e. g. in neat water: 3,8 · 108 (MAA), 2,2 · 108 (AA), and in H2O/CH3CN (1:1, v/v): 1,8 · 107 (St), 1,2 · 108 (MMA), 8,4 · 107 (AN).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1991.021921010
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  • 4
    Electronic Resource
    Electronic Resource
    Studies of the metathesis polymerization and copolymerization of syn- and anti-7-methylnorbornene initiated by the tungsten-carbene complex (1990)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 191 (1990), S. 2237-2251 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The tungsten-carbene complex was used to initiate the metathesis polymerization of syn-and anti-7-methylbicyclo [2.2.1] hept-2-ene (Ms and Ma). Two kinds of experiment were performed:(i) the reactions were followed at low monomer/initiator ratios by 1H NMR spectroscopy at 220-250K; (ii) polymers and copolymers of Ms and Ma were prepared at room temperature and their microstructure analysed by 13C NMR spectroscopy. The propagating tungsten-carbene species derived from both Ma could be detected. Some rate constants were evaluated for various steps in the mechanism. A polymer of Ms was prepared for the first time, containing 90% trans double bonds and probably isotactic. After hydrogenation this polymer exhibits two first-order transitions, with DSC maxima at 179 and 230°C. Hydrogenated atactic polymers of Ma and of norbornene also exhibit first-order transitions. Conditions are described for the preparation of block and tapered block copolymers of Ma and Ms.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1990.021911003
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  • 5
    Electronic Resource
    Electronic Resource
    Addition of chlorofluorocarbene to poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) and poly(1,1-dimethyl-1-sila-cis-pent-3-ene): Characterization of chlorofluorocyclopropanated polymer microstructures by 1H-, 13C-, 19F-, and 29Si-NMR spectroscopy (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 1789-1798 
    Details
    ISSN: 0887-624X
    Keywords: chlorofluorocyclopropanated polymers ; carbosilane polymers ; thermal stability ; synthesis ; characterization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chlorofluorocarbene, generated by the sodium iodide catalyzed decomposition of phenyl(dichlorofluoromethyl)mercury, adds to the carbon-carbon double bonds of poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) (I) and poly(1,1-dimethyl-1-sila-cis-pent-3-ene) (II) to yield poly(3,4-chlorofluoromethylene-1-methyl-1-phenyl-1-sila-cis-pent-3-ene) (CIFC-I) and poly(3,4-chlorofluoromethylene-1,1-dimethyl-1-sila-cis-pent-3-ene) (CIFC-II). Similarly, two series of random partially chlorofluorocyclopropanated polymers have been prepared. The microstructures of these adduct polymers have been determined by 1H-, 13C-, 19F-, and 29Si-NMR spectroscopy. The glass transition temperatures (Tg's) depend on the extent of chlorofluoropropanation of these polymers. These copolymers become less thermally stable as the extent of chlorofluorocyclopropanation increases. © 1993 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310718
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  • 6
    Electronic Resource
    Electronic Resource
    Crystalline inclusion compounds of tetrabenzo-18-crown-6 with uncharged organic molecules. Solid-state structure of the nitroethane complex (1994)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 15 (1994), S. 231-245 
    Details
    ISSN: 1573-1111
    Keywords: Inclusion compounds ; X-ray crystal structure analysis ; tetrabenzo-18-crown-6 ; nitroethane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Tetrabenzo-18-crown-6 (1) shows distinct solid-state inclusion properties towards a number of OH-acidic, CH-acidic and low-polar uncharged organic molecules. The single crystal X-ray analysis of the inclusion complex between1 and EtNO2 (1∶1) is reported. Crystals are monoclinic,P21/c, witha=12.887(1),b=19.365(2),c=10.776(1) Å, β=96.33(2)o,D c=1.321g cm−1,Z=4. The host macroring has a conformation similar to a ‘dentist's-chair’. The complex is stabilized mainly by C−H...O type interactions involving the methyl group of the EtNO2 guest molecule which is highly disordered. The nitroethane guests are trapped in channels formed by the host macrocycles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00709069
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  • 7
    Electronic Resource
    Electronic Resource
    Crystal structure of an uncomplexed 25-crown-7 comprising one 2,6-pyridino and two 1,4-benzo condensations (1994)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 18 (1994), S. 1-8 
    Details
    ISSN: 1573-1111
    Keywords: (1,4)Dibenzo(2,6)pyridino-25-crown-7 ; X-ray crystal structure analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Single crystal X-ray analysis of the uncomplexed crown macroring 1 is reported. Crystals are triclinic, $$P\bar 1$$ , witha=10.809(1),b=10.945(1),c=10.256(1) Å, α=107.85(1), β=104.15(1), γ=87.27(1)°,D c=1.318 g cm−3,Z=2. Three torsion angles in the macrocycle take upgauche conformations in contrast to the usualanti conformation. The crystal structure is stabilized by intramolecular van der Waals forces and weak C−H...O and C−H...N hydrogen bond attractions. Stacking of pyridine rings is a noticeable packing feature in the crystal lattice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00706934
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  • 8
    Electronic Resource
    Electronic Resource
    Host-guest binding in two coordinatoclathrates of 1,1′-binaphthyl-2,2′-dicarboxylic acid. x-ray crystal structures of the inclusion compounds with 1-propanol (2 : 1) andt-butanol (1 : 1) (1991)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 10 (1991), S. 355-366 
    Details
    ISSN: 1573-1111
    Keywords: Inclusion compounds ; X-ray crystal structure analysis ; coordinatoclathrates ; carboxylic host ; guest alcohos ; hydrogen bonding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract 1,1'-Binaphthyl-2,2'-dicarboxylic acid (1) forms crystalline inclusion compounds with 1-PrOH (2:1) andt-BuOH (1:1). X-ray crystal structures of the two inclusion compounds are reported. Crystals of1·1-PrOH (2: 1) show triclinic ( $$P\bar 1$$ ) symmetry with the unit cell dimensionsa = 10.160(1),b = 14.050(2),c = 15.167(1) Åα = 100.37(1),β = 104.40(1), andγ =94.82(1)°. Crystals of1s·t-BuOH (1: 1) are monoclinic (P21/n) with the cell dimensionsa = 10.603(5),b = 14.377(4),c = 15.664(7) Å,β = 104.24(4)°. In both structures, H-bonded loops involving host −000H functions and guest −OH groups establish the supramolecular association. They relate these coordinatoclathrates to previous alcohol inclusions of1. Due to the unusual 2:1 (host: guest) stoichiometry, additional dimer-like interactions between −000H groups of host molecules are found in the 1-PrOH inclusion compound. From the point of view of topology these structures can be referred to as channel inclusion compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01133320
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  • 9
    Electronic Resource
    Electronic Resource
    Solid-state binding of dimethyl sulphoxide involving carboxylic host molecules. X-ray crystal structures of four inclusion species (1990)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 8 (1990), S. 275-287 
    Details
    ISSN: 1573-1111
    Keywords: Inclusion compounds ; X-ray crystal structure analysis ; DMSO clathrates ; hydrogen bonding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal structures of four dimethyl sulphoxide (DMSO) inclusion compounds with different carboxylic acid hosts,1–4, have been studied by single crystal X-ray analysis. Crystals of thetrans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid inclusion compound (1a), [1 · DMSO (1: 1)] show monoclinic (P21/n) symmetry with the unit cell dimensionsa = 11.522(4),b = 18.658(2),c = 8.709(1) Å and β = 98.92(2)°. The clathrate of the 9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid (2a), [2 · DMSO (1: 2)] is triclinic (PĪ) with the cell dimensionsa = 15.043(7),b =9.657(4),c = 8.118(7) Å, α = 101.81(5), β = 96.05(4) and γ = 100.04(4)°. Triclinic (PĪ) symmetry is shown also by the inclusion compound of 9,10-dihydro-9,10-ethanoanthracene-11-monocarboxylic acid (3a) [3 · DMSO (1:1)] with the cell dimensionsa=6.3132(1),b=7.9846(2),c=17.5314(4) Å, α = 96.46(2), β = 87.08(2) and γ = 106.02(2)°. The 9,9′-bianthryl-2-monocarboxylic acid clathrate (4a) [4 · DMSO (1:1)] is monoclinic (P21/n) and the cell dimensions area = 19.625(18),b = 8.817(1),c = 14.076(8) Å and β = 97.92(6)°. In all these structures, the hosts show the same basic recognition pattern for the DMSO guest, involving a strong O-H ... O bond from the COON to the S=O group, and a possible C-H ... O type interaction between the carbonyl O atom of the host and a CH3 group of the guest. The crystals consist of discrete host-guest aggregates which are mainly held together by weak intermolecular interactions of the Van der Waals' type. The stoichiometries of the aggregates are, however, different.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01041884
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  • 10
    Electronic Resource
    Electronic Resource
    On the dependence of molecular conformation on the type of solvent environment: A molecular dynamics study of cyclosporin A (1990)
    New York : Wiley-Blackwell
    Biopolymers 29 (1990), S. 1669-1687 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dependence of the conformation of cyclosporin A (CPA), a cyclic undecapeptide with potent immunosuppressive activity, on the type of solvent environment is examined using the computer simulation method of molecular dynamics (MD). Conformational and dynamic properties of CPA in aqueous solution are obtained from MD simulations of a CPA molecule dissolved in a box with water molecules. Corresponding properties of CPA in apolar solution are obtained from MD simulation of CPA in a box with carbontetrachloride. The Results of these simulations in H2O and in CCl4 are compared to each other and to those of previous simulations of crystalline CPA and of an isolated CPA molecule.The conformation of the backbone of the cyclic polypeptide is basically independent of the type of solvent. In aqueous solution the β-pleated sheet is slightly weaker and the γ-turn is a bit less pronounced than in apolar solution. Side chains may adopt different conformations in different solvents. In apolar solution the hydrophobic side chain of the MeBmt residue is in an extended conformation with its hydroxyl group hydrogen bonded to the backbone carbonyl group. In aqueous solution this hydrophobic side chain folds over the core of the molecule and the mentioned hydrogen bond is broken in favor of hydrogen bonding to water molecules. The conformation obtained from the MD simulation in CCl4 nicely agrees with experimental atom-atom distance data as obtained from nmr experiments in chloroform. In aqueous solution the relaxation of atomic motion tends to be slower than in apolar solution.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360291214
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