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  • Physics  (18)
  • binding ability  (1)
  • charge separation  (1)
  • ethyl viologen  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Trans-cis Photoisomerization of 1-Methyl-4-(4′-hydroxystyryl)pyridinium in inclusion complexes ofβ-cyclodextrin and its derivatives (1992)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 13 (1992), S. 349-359 
    Details
    ISSN: 1573-1111
    Keywords: 1-methyl-4-(4′-hydroxystyryl)pyridinium ; trans-cis photoisomerization ; betain ; charge separation ; cyclodextrin ; inclusion complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The effects of β-cyclodextrin (β-CyD), heptakis(2,6-di-O-methyl)-β-cyclodextrin (DMβCyD) and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TMβCyD) ontrans-cis photoisomerization of 1-ethyl-4-(4′-hydroxystyryl)pyridinium (POH) have been studied in aqueous solutions. The ratio of [cis]/[trans] for POH in the photostationary state at pH 8.54 was remarkably reduced by the presence of βCyD or DMβCyD. The reduction of the [cis]/[trans] ratio in the photostationary state was explained in terms of the shift of the equilibrium of POH + trans ⇌ PO trans + H− toward PO trans formation. The binding constants of βCyD and DMβCyD for PO trans were 2.00- and 1.36-fold larger than those for POH + trans , respectively. The binding constants of TMβCyD for both species are much smaller than those of βCyD and DMβCyD. This result indicates that PO trans , which has a betain structure, forms stable complexes with βCyD and DMβCyD with its hydrophobic parts inside and the charged parts outside the CyD cavities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01133234
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  • 2
    Electronic Resource
    Electronic Resource
    The conformational and binding properties of ethylbipyridinio-modifiedβ-Cyclodextrin using induced circular dichroism (1991)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 10 (1991), S. 443-451 
    Details
    ISSN: 1573-1111
    Keywords: Cyclodextrin ; ethyl viologen ; binding ability ; conformation ; steroidal guest ; complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The conformational and binding properties of mono-6-deoxy-6[4-(1-ethyl-4-pyridinio)-1-pyridinio]-β-cyclodextrin (1) in complex formation with some guest compounds were examined by induced circular dichroism (ICD) spectra in aqueous solution. Compound 1 showed much stronger binding ability for some guest compounds (1: 1 complexes), compared withβ-cyclodextrin (β-CDx) and a positively charged β-CDx [C-6-mono-pyridino-β-CDx (2)]. Marked conformational changes of1 (the spatial position of the ethyl viologen (C2V2+) group relative to the cavity in 1) were observed upon complex formation with some guests like 1-adamantanecarboxylic acid (ACA) and sodium cholate (SC).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01061075
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  • 3
    Electronic Resource
    Electronic Resource
    Thermal properties and solubility of ordered aromatic polyamides containing a methyl-substituted phenylene linkage (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 15 (1977), S. 2997-3008 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ordered aromatic polyamides and copolyamides were prepared by the polycondensation of terephthaloyl and isophthaloyl dichlorides with symmetrical diamines containing preformed amide linkages derived from unsymmetrical methyl - substituted aromatic diamines at low temperature. Thermal properties and solubilities of the ordered polyamides were compared with those of the corresponding random polyamides. There was little difference between thermal stabilities of the ordered polyamide and the corresponding random one, while the former was less soluble in organic solvents than the latter, depending on the extent of hydrogen bonding of the amide groups. The thermal stability of the alternating copolyamides containing both terephthaloyl and isophthaloyl groups as acid components was less than that of the corresponding homopolymers having either a terephthaloyl or an isophthaloyl group, and the solubility of the former resembled that of the corresponding ordered homopolysiophthalamides in accord with the extent of hydrogen bonding of the amide groups in both polymers.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.170151214
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  • 4
    Electronic Resource
    Electronic Resource
    Structure and properties of poly(2,5-dimethylterephthalamides) (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 16 (1978), S. 361-370 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Six methyl-substituted wholly aromatic polyamides were synthesized from the reaction of 2,5-dimethylterephthaloyl chloride with p-phenylenediamine, its 2,5-dimethyl and 2-methyl derivatives, m-phenylenediamine, or its 2-methyl and 4-methyl derivatives by solution polycondensation at low temperature. The x-ray diffraction diagrams of the polyamides obtained exhibit crystal patterns. Density values range from 1.26 to 1.37 g/cm3. NMR spectra determined in concentrated H2SO4 solution are reported. Poly(2,5-dimethylterephthalamides) have lower thermal stability than the corresponding polyterephthalamides. The increase in solubility of polyamide by the introduction of the 2,5-dimethylterephthaloyl linkage is accompanied by a decrease in thermal stability. The effect of methyl substituents on thermal properties and solubility is discussed in terms of the packing of polymeric molecules and the extent of hydrogen bonding of the amide groups.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.170160206
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  • 5
    Electronic Resource
    Electronic Resource
    Photoisomerization of 1,2-diphenylcyclopropane sensitized by polypeptides containing naphthalene groups in their side chain (1974)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 12 (1974), S. 1841-1849 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(γ-1-naphthylmethyl L- and DL-glutamate) (PNLG and PNDLG) and copolypeptides of γ-1-naphthylmethyl L-glutamate and γ-benzyl-L-glutamate were used as sensitizers for isomerization of trans-1,2-diphenylcyclopropane. Quantum yields relative to that of 1-methylnaphthalene were measured in dichloroethane (DCE) and dichloroacetic acid (DCA). The relative quantum yield in DCE was smaller than unity for PNLG, but greater than unity for PNDLG and copolypeptides. The result is discussed in terms of increased effective collisional radius and energy trapping by excimer formation. The relative quantum yields in DCA were close to unity except for the copolypeptides of higher γ-benzyl L-glutamate content. This suggests that the naphthalene groups act in the same manner as their monomeric counterparts in the random conformation and that the greater proportion of γ-benzyl L-glutamate in the copolypeptides lowers the quantum efficiency because trans-1,2-diphenylcyclopropane must penetrate through the polymeric medium in order to encounter the excited naphthalene.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1974.170120824
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesis of poly-L-naphthylalanine and its secondary structure (1975)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 13 (1975), S. 2751-2762 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polypeptides derived from L-naphthylalanine and γ-benzyl L-glutamate were prepared. Conformational properties in solution were investigated by circular dichroism (CD) and infrared spectra on the soluble copolymers, and the copolymers were assumed to take the right-handed α-helical conformation. By the addition of trifluoroacetic acid, a transition of side-chain arrangement is induced simultaneously with the conformational transition of the peptide backbone for the copolymer with the highest content of L-naphthylalanine residues. Fluorescence spectra of the copolymers show no excimer emission, which is evidence for the rigid orientation of the side-chain naphthyl groups. The infrared spectrum and x-ray diagram of poly-L-naphthylalanine do not rule out the helical conformation in the solid state.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1975.170131210
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  • 7
    Electronic Resource
    Electronic Resource
    Anionic polymerization of styrene in the presence of pyridine (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 14 (1976), S. 1097-1105 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An interesting effect of pyridine on the anionic polymerization of styrene in THF is described. Pyridine forms a complex with living polystyrene and greatly slows the polymerization rate without changing the degree of polymerization. From kinetic and spectroscopic studies, it was clear that there exist two active species in this system and the complex between living polystyrene and pyridine was of the 1:1 type, which itself had a weak ability to grow. The formation constant of the complex K was found to be about 4 × 105 l./mole. The effect of substituted pyridine was also studied and the nature of the complex was discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.170140507
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  • 8
    Electronic Resource
    Electronic Resource
    Synthesis of polybenzimidazoles with sulfonic acid groups (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 15 (1977), S. 1309-1318 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Sulfoterephthalic acid (STA) and disulfoisophthalic acid (DSIA) were synthesized through the sulfonation and the oxidation of m- and p-xylene. The polycondensation reactions of STA and DSIA with aromatic tetraamines gave polybenzimidazoles which contained one or two sulfonic acid groups for each repeating unit. The polymer obtained was soluble in sulfuric acid, some organic solvents, and aqueous strong alkaline solution. The polymers were stable up to 400°C, but they gave polybenzimidazoles above 400°C by eliminating sulfonic acid groups, instead of ring closure.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.170150602
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  • 9
    Electronic Resource
    Electronic Resource
    Study on wholly aromatic polyamides containing methyl-substituted phenylene linkage (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 15 (1977), S. 1905-1915 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to study the influence of chemical modification on properties of polyamides, wholly aromatic polyamides have been synthesized from p-phenylenediamine, its 2,5-dimethyl and 2-methyl derivatives, m-phenylenediamine, its 2-methyl and 4-methyl derivatives, and terephthaloyl and isophthaloyl dichlorides by solution polycondensation at low temperature. The thermal stability and solubility of the methyl-substituted polyamides were compared with those of unsubstituted ones. The introduction of methyl groups in a polymeric chain led to a decrease in their thermal stability to different degrees depending on the positions of methyl groups, accompanied by an increase in their solubility. The unsymmetrical introduction of methyl groups in benzene rings had a greater effect on the increase in solubility of polyamide than did symmetrical methyl groups.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.170150812
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  • 10
    Electronic Resource
    Electronic Resource
    Reaction between ethanol and silicon-hydrogen of poly(p-vinylphenyldimethylsilane) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 6 (1968), S. 1643-1653 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A kinetic approach to the polymer reaction, with KOH as catalyst, between ethanol and poly(p-vinylphenyldimethylsilane) containing silicon-hydrogen as a functional group on the side chain was carried out. The rate equation was obtained by measuring the initial rate of the model reaction as v = k[KOH] [SiH] [EtOH] in benzene and v = k[KOH] [SiH] in methyl ethyl ketone. It was observed that the rate of reaction was affected by the polarity of the solvents. In the polymer reaction the rate constant decreased markedly with increasing ethanol concentration. A change of viscosity of the polymer in various solvents was observed to have a good correlation with the decrease in reaction rate in corresponding solvents. In mixed solvents, consisting of both good and poor solvents for the polymers, the reaction rate depended upon two factors, the entanglement of the polymer chain and the polarity of the solvents. The equivalent globular model of the polymer chain is suggested for study of the polymer reaction. A schematic local-distribution curve of the reaction species is proposed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.150060622
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