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  • 1
    Electronic Resource
    Electronic Resource
    Nuclear magnetic resonance studies on poly(alkyl propenyl ether) and model compounds. 2. Calculation of carbon-13 nuclear magnetic resonance chemical shifts (1981)
    s.l. : American Chemical Society
    Macromolecules 14 (1981), S. 1008-1012 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma50005a020
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  • 2
    Electronic Resource
    Electronic Resource
    Nuclear magnetic resonance studies on poly(alkyl propenyl ether) and model compounds. 1. Conformational analysis of model compounds (1981)
    s.l. : American Chemical Society
    Macromolecules 14 (1981), S. 1004-1008 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma50005a019
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  • 3
    Electronic Resource
    Electronic Resource
    Nuclear magnetic resonance studies on polymer carbanions, 1. Living polystyrene and its model compounds (1980)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 1923-1934 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 1H and 13C NMR investigations were carried out on polystyryl carbanions and model compounds for the active chain end of living polystyrene, changing counter cation (Li, K, and Cs), solvent, and temperature. The structure of the model compounds with K and Cs as counter cation was planar with sp2-hybridized α-carbon, which indicates strongly hindered rotation of the phenyl ring. For the model compound with lithium as counter cation, the phenyl ring rotation was hindered at lower temperatures. The 13C—1H coupling constants of the compound indicated less sp2 character of α-carbon. The differences in the chemical shifts of the two ortho or meta carbons depended on the type of counter cation, suggesting an interaction between counter cation and phenyl ring. Quantum chemical calculations on the structure of the model compounds were carried out and the results were compared with the excess charge distributions calculated from 13C NMR chemical shifts.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1980.021810913
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  • 4
    Electronic Resource
    Electronic Resource
    Nuclear magnetic resonance studies on polymer carbanions, 2Part 1: cf.2.. Model compounds for α-methylstyrene and α-methylstyrene tetramer dianions (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 1533-1540 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 1H and 13C NMR spectra of model compounds for the poly-α-methylstyryl anion, 2-lithio, 2-potassio, and 2-cesio-2-phenylbutane, were determined. The lithium compound had a higher charge density at the α-carbon and a lower charge on the phenyl ring than the other compounds and exhibited phenyl ring rotation at higher temperatures. The activation energy was calculated to be 61, 0 kJ/mol. The potassium and cesium compounds did not show phenyl ring rotation at 80°C. Quantum chemical calculations indicated that the larger cations interact with the phenyl ring especially with the ortho carbons. 13C NMR spectra of α-methylstyrene tetramer dianion with sodium and potassium as counter cation were also measured and compared with those of the model compounds.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021820524
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  • 5
    Electronic Resource
    Electronic Resource
    Stereochemistry of a model reaction for the propagation reaction in the cationic polymerization of alkyl propenyl ethers (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 2421-2427 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The stereochemistry of the acetal addition to alkyl propenyl ethers was investigated as a model reaction for the cationic polymerization of propenyl ethers. The diastereomers of the acetal adducts were identified by model compounds with similar structure. The modes of both double bond opening and monomer addition were determined. It was demonstrated that the mode of double bond opening is independent of the geometrical structure of the ethyl propenyl ether and mainly threo-opening takes place, whereas the mode of monomer addition is dependent on the geometrical structure of the monomer.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021820905
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  • 6
    Electronic Resource
    Electronic Resource
    Polymerization of methyl methacrylate with phenylmagnesium bromide  -  stereoregularity, molecular weight distribution and polymerization mechanism  -  (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 2905-2918 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The stereoregularity and molecular weight distribution of poly(methylmethacrylate)s prepared with phenylmagnesium bromide or diphenylmagnesium as catalyst in tetrahydrofuran/toluene mixed solvents were investigated in detail. Some of the polymers were fractionated according to molecular weight or by adsorption with silical gel and the stereoregularities of the fractions were determined. An eneidic mechanism of propropagation was proposed based on the experimental results.1H NMR spectroscopy of deuterated phenylmagnesium bromide and of its reaction with methyl methacrylate indicated that an eneidic mechanism resulted from a Schlenk type equilibrium, which is shifted to the diphenylmagnesium species at low temperatures and in nonpolar solvents.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021821034
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  • 7
    Electronic Resource
    Electronic Resource
    Conformational analysis of poly(methyl acrylate) by 1H nuclear magnetic resonance spectroscopy (1982)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 183 (1982), S. 185-192 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The 1H NMR spectra of poly(methyl acrylate-d1) +CHD—CH(COOCH3)+n were measured in o-dichlorobenzene and CDCl3 in the temperature range between - 20 and 145°C. Trans and gauche coupling constant were determined from the temperature dependence of the geminal coupling constants, neglecting g' conformers. It was estimated that the proportion of trans conformer is 1,5 to 1,9 times that of the gauche conformer in this temperature range.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1982.021830116
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  • 8
    Electronic Resource
    Electronic Resource
    The stereoregularity of poly(methyl methacrylate)s formed in the presence of highly syndiotactic poly(methyl methacrylate)s (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 2291-2297 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Methyl methacrylate (MMA) was radically polymerized in the presence of highly syndiotactic deuterated or undeuterated poly(methyl methacrylate)s. In contrast to observations found in the literature no increase in isotacticity was observed. The stereoregularity of the polymers formed in the presence of an undeuterated PMMA as matrix was found by 1H NMR spectroscopy to be about the same as that in polymers prepared without any matrix, except the polymers formed in the early stage of polymerization which show a little lower syndiotacticity. Determinations of triad tacticities of polymers formed in the presence of deuterated PMMA, gave values of syndiotacticity a little higher than in the case of undeuterated matrixes. The polymer formed in the graft copolymerization of MMA onto pre-irradiated syndiotactic PMMA was fractionated by GPC. The high molecular weight fraction showed a lower syndiotacticity than that of lower molecular weight.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.021851106
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  • 9
    Electronic Resource
    Electronic Resource
    Nuclear magnetic resonance studies on polymer carbanions, 5Part 4: cf.11.. Polystyryl carbanion with lithium as counter cation and its dimer model compounds (1986)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 187 (1986), S. 2199-2208 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Oligostyryllithium was synthesized by the reaction of sec-butyllithium with styrene in diethyl ether at -40°C. Dimer model anions (counter cations: Li and K) of the growing chain ends were synthesized by metallation of 1-methoxy-1,3-diphenylpropane. The structures of the lithium compounds were corroborated by 13C NMR spectroscopy and compared with those of the potassium compounds. As for polystyryllithium and its model compounds, the charge density on the α-carbon increased and that on the phenyl ring of the growing end decreased with increasing molecular weight, while, in polystyrylpotassium and its model compounds, the charge density on the α-carbon increased and the one on the phenyl ring did not change with increasing molecular weight. The temperature change of the 1H NMR spectrum of oligostyryllithium in diethyl ether indicated rotation around the C-1—Cα bond at lower temperatures than in tetrahydrofuran, but the activation energy was the same in both solvents. T1 values of the phenyl carbons in model compound 2b were one to two orders of magnitude shorter than those of the protonated compound.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1986.021870916
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  • 10
    Electronic Resource
    Electronic Resource
    Copolymerization of (-)- and (±)-menthyl acrylates (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 2853-2860 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: An Copolymeren aus (-)- und (±)-Menthylacrylaten wurden Drehwerte und das Verhältnis der optischen Dichten bei 1372 und 1235cm-1 (D1372/D1235) als Maß für die Stereoregularität bestimmt. Die Drehwerte radikalisch hergestellter Poly[(-)-menthylacrylate] waren höher und die D1372/D1235-Werte waren niedriger als bei anionisch hergestellten Copolymeren. Die D1372/D1235-Werte der anionischen Copolymeren aus (-)- und (±)-Menthylacrylaten nehmen ab mit sinkendem Gehalt des (-)-Monomeren im Ausgangsgemisch, was auf eine Abnahme der Isotaktizität in den Copolymeren hinweist. Hierdurch wurden die asymmetrischen Effekte der optisch aktiven Menthylgruppen auf die Konfiguration der Hauptketten bei anionischen Polymerisationen bestätigt.
    Notes: Copolymerizations of (-)- and (±)-menthyl acrylates were carried out and the optical rotation and the optical density ratio, D1372/D1235, which was an index of stereoregularity, were determined. The optical rotation of radically obtained poly[(-)-menthyl acrylates] were higher and the optical density ratios were lower than those of anionically obtained polymers. The optical density ratios of the anionically obtained copolymers of (-)-and (±)-menthyl acrylates descreased with the decrease of (-)-monomer content in the starting monomers, indicating the decrease in the isotacticity of the copolymers. Thus, the asymmetric effects of optically active menthyl groups on the main chain configurations in anionic polymerization were ascertained.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021761007
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