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  • 1
    Electronic Resource
    Electronic Resource
    Conformational and configurational study of 1,3-dioxolanes by proton and carbon NMR spectroscopy (1995)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 33 (1995), S. 167-173 
    Details
    ISSN: 0749-1581
    Keywords: 1,3-dioxolanes ; NOE ; vicinal proton-proton coupling ; configurational analysis ; conformational analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The configurational and conformational properties of six 4-trimethylammoniummethyl 2,2-disubstituted 1,3-dioxolanes were studied using NOE experiments and vicinal coupling constants. Selective 1D NOE experiments proved to be effective tools in the configurational assignment of C-2 relative to C-4. The preferred conformation of the dioxolane ring and the exocyclic group at C-4 was obtained by employing vicinal coupling constants and NOE results. The 1H and 13C NMR chemical shifts show stereochemically dependent trends. Quantitative analysis of conformer populations was performed using Haasnoot et al's equation. The —N+(CH3)3 group was found to be synclinal with respect to the heterocyclic O-3 atom and points outside the ring. When a phenyl group is present at C-2, the 4-CH2N+ -  group in a trans relationship to the 2-phenyl ring was found to occur prevalently in a pseudo-axial orientation, whereas it was established to be prevalently pseudo-equatorial when cis with respect to the phenyl ring.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260330303
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Complete assignment of the aliphatic chains in dimers, trimers and polymer of 3-hexylthiophene through 2D-NMR spectroscopy (1995)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 33 (1995), S. 657-663 
    Details
    ISSN: 0749-1581
    Keywords: NMR ; 1H NMR ; 13C NMR ; dimers and timers of 3-hexylthiophene ; poly(3-hexylthiophene) ; 1H, 13C inverse detection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1H and 13C signals of the hexyl chains of the title compounds were fully assigned. The regiochemical features of the aliphatic region of proton and carbon spectra were analysed in dimers and trimers. Dimers and trimers proved to be reliable model compounds in the regiochemical assignment of poly(3-hexylthiophene) even when the aliphatic region of proton and carbon spectra was involved. The chemical shifts of the protons of CH2(α)s and of the hexyl chain as a whole and those of the first three aliphatic carbons appear to be the most significant.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260330807
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Alkylthio-substituted oligothiophenes: the influence of the alkyl chain length on the solid-state and solution properties of 4,4′-bis(butylthio)-2,2′-bithiophene (1996)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 47 (1996), S. 265-268 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A solid-state (single crystal X-ray, IR, DSC) and solution (1H NMR nuclear Overhauser effect (NOE) and longitudinal relaxation times (T1)) study of 4,4′-bis(butylthio)-2,2′-bithiophene is reported. The two thienyl rings are coplanar and in an anti orientation in the solid state, whereas a low amount of syn form is present in solution. The n-butylthio chain adopts a fully extended, nearly idealized, anti conformation in the crystal, with all the non-H atoms of the whole molecule strictly coplanar, despite the molecular length, but does not show a preferred orientation in solution. The observed changes on passing from the solid to the solution state are indications of the potential solvatochromic and thermochromic properties of β-butylthio-substituted oligomers and polymers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1996.010470603
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    Paper (German National Licenses)
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