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  • 1
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 6 (1974), S. 322-323 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The complex between triethylaluminium and diethylether has been studied by 1H NMR; separate signals have been observed for free and bonded triethylaluminium. From the area ratios, a 1:1 stoichiometry is demonstrated. At higher ether concentrations, chemical shift measurements prove that other complexes do not appear.
    Notes: La complexation entre le triéthylaluminium et l'éther diéthylique a été étudiée par résonance magnétique du proton. On a pu observer des signaux distincts pour le triéthylaluminium libre et le triéthylaluminium lié. Une stoechiométrie 1:1 est démontrée grâce aux rapports des aires de ces signaux. A plus haute concentration d'éther, des mesures de déplacements chimiques prouvent qu'il n'apparaît pas d'autres complexes.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 7 (1975), S. 633-634 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The value of direct couplings in o-dichlorobenzylfluoride, obtained from nematic phase NMR, lead to the conclusion that the most stable form is such that the fluorine atom is in a plane perpendicular to the benzene ring. However, the complete intepretation of these couplings in terms of geometrical parameters tends to indicate a modification of orientation with internal rotation of CH2F.
    Notes: La valeur des couplages directs dans l'ortho-dichlorofluorure de benzyle, obtenus par RMN en phase nématique, permet d'affirmer que la position la plus stable du CH2F est telle que le fluor se trouve dans un plan perpendiculaire au cycle benzénique. L'interprétation complète de ces couplages en fonction de la géométrie de la molécule laisse cependant supposer une modification de l'orientation intervenant en même temps que la rotation du groupement CH2F.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 19 (1982), S. 1-5 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular dynamics and the association of 2-pyrrolidone, δ-valerolactam and ∊-caprolactam in H2O and CCI4 solutions have been investigated by 13C nuclear magnetic relaxation. With the aim of unambiguously establishing 13C assignments the following parameters have been measured: carbon chemical shifts, one-bond carbon-proton coupling constants and one bond carbon-carbon coupling constants. In the particular case of 2-pyrrolidone, the 13C relaxation times do not provide enough information in order to study in detail the dynamics of the molecule. 15N Relaxation for the neat liquid has proved to be a valuable complement for totally analysing the anisotropic motion of this lactam.
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 15 (1981), S. 344-346 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An indirect method is employed for determining the 15N parameters at the natural abundance level in a series of simple acyclic and cyclic amides. The one bond coupling constant, 1J(15N1H), and the 15N chemical shift are measured as a function of the carbonyl substituent group or the ring size and the nature of the solvent (CCl4 or H2O). These 15N parameters are related to the amide bond structure, the nitrogen configuration and possible intermolecular hydrogen bonding (amide-amide or amide-water).
    Additional Material: 2 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 20 (1982), S. 51-53 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is proposed for eliminating baseline distortions due to spurious ringings in Fourier transform NMR spectra involving broad resonances. It is based on the pulse sequence (π/2)-(Acquistion/Add)-π-τ-(π/2) (Acquisition/Subtract). τ is of the order of, or shorter than, the spectrometer recovery time. The sensitivity of the method is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 23 (1957), S. 223-232 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The authors show there is a fair agreement between the experimental values of electric moments of polyoxyethyleneglycol and diethoxypolyoxyethyleneglycol (the degrees of polymerization of which are included between 2 and 230) and the theoretical values obtained when taking into account steric hindrances and short range interactions. It is possible to show why the mean square electric moment \documentclass{article}\pagestyle{empty}\begin{document}$ \overline {\mu ^2 } $\end{document} remains proportional to the degree of polymerization for usual polymer chains. This means that the measurements of \documentclass{article}\pagestyle{empty}\begin{document}$ \overline {\mu ^2 } $\end{document} are independent of the “excluded volume” effect. They give us the possibility of the evaluation of short range interactions even in solvents which are not θ solvents. Thus we have been able to show in the case of polymethyl methacrylate that these interactions are independent of solvent and temperature, within experimental errors.
    Notes: Les auteurs ont mesuré les moments électriques des polyoxyéthylèneglycols et des polyoxyéthylèneglycols diéthoxylés de degré de polymérisation compris entre 2 et 230. Ils ont calculé, en tenant compte des interactions, les valeurs théoriques correspondantes qui sont en accord avec les résultats expérimentaux. Ils montrent ensuite que le carré moyen du moment électrique \documentclass{article}\pagestyle{empty}\begin{document}$ \overline {\mu ^2 } $\end{document} est, dans les cas usuels, proportionnel au degré de polymérisation, ce qui signifie que l'“effet de volume” n'a pas d'influence sur la grandeur de \documentclass{article}\pagestyle{empty}\begin{document}$ \overline {\mu ^2 } $\end{document}. Ils en déduisent une méthode de mesure des interactions à courte distance dans un solvant quelconque. L'étude du polyméthacrylate de méthyle montre que ces interactions sont indépendantes du solvant et de la température, aux erreurs d'expérience près.
    Additional Material: 1 Ill.
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  • 7
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: We have investigated the irradiation of aqueous solutions of polyoxyethylene glycol by radiocobalt γ rays. Our results demonstrate the existence of two opposite mechanisms, the one leading to crosslinking of the polymer and the other to degradation.
    Notes: Nous avons etudié l'irradiation de solutions aqueuses de polyoxyèthyléneglycol à l'aide des rayons γ issus du radiocobalt. Dans une première série d'expériences les solutions ont été irradiées en présence d'air. Ces resultats montrent l'existence de deux mécanismes opposés dont l'un conduit au pontage du polymere et l'autre à la dégradation.
    Additional Material: 3 Ill.
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