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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of solution chemistry 23 (1994), S. 1317-1330 
    ISSN: 1572-8927
    Schlagwort(e): Absorption sprectra ; dyes ; merocyanines ; solvent effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Solvent effects on the lowest-energy electronic transitions of two merocyanines derived from quinoline have been studied using nine different solvent parameters reported in the literature. Relative merits and deficiencies of different parameters have been assessed. From the correlation results, attempts have been made to propose a solute-solvent interaction mechanism. For an assorted set of 19 solvents, as well as for a set of nine hydroxylic solvents, excellent results are obtained with correlation equation involving ET(30) and Hilderbrand's solubility parameter δH.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of biological physics 12 (1984), S. 12-16 
    ISSN: 1573-0689
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Physik
    Notizen: Abstract Conformational properties of the nucleoside antibiotic 2′-amino-2′-deoxyguanosine have been investigated by the PCILO method along with those of its parent nucleoside, guanosine. This antibiotic, formed by replacement of the 2′-hydroxyl group by an amino group in guanosine, shows anti-tumor activity and also inhibits RNA and protein syntheses. Both C(2′)-endo and C(3′)-endo sugar conformations have been considered in the computations. The results indicate striking similarity between the conformations of the antibiotic and the parent nucleoside, particularly in simulated aqueous environment. The biological implication of this result in terms of the antibiotic activity is discussed.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 20 (1981), S. 357-367 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: PCILO computations have been carried out on the conformation of 3'-deoxyadenosine (cordycepin) and 3'-amino-3'-deoxyadenosine. These nucleoside antibiotics results as a consequence of modification in the sugar part of adenosine. Both C(2')-endo and C(3')-endo sugar puckerings have been considered in the computations and the results obtained indicate that these nucleoside antibiotics have very similar conformational preferences as compared to those of the parent nucleoside adenosine. This similarity which is quite marked in aqueous solution has important biological significance.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 27 (1985), S. 135-144 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: PCILO computations have been carried out on the conformation of p-dimethylaminobenzylidene-p-nitroaniline [I(m)], p-nitrobenzylidene-p-dimethylaminoaniline [I(n)] and the corresponding stilbene [II(a)] and azobenzene [II(b)] derivatives. The aniline rings in Im and In are found to be twisted out of the plane containing the central atoms by 60° and 30°, respectively. The two phenyl rings in case of II(a) are twisted out of plane in opposite directions by 30° each. II(b) was found to be planar. The results have been compared with the earlier experimental findings and used as a possible explanation for the visible absorption spectra of the four molecules.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 595-612 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Conformational studies on some p-dimethylamino β-aza and β-aza (with respect to the dimethylamino phenyl ring) styryl dyes derived from quinoline-4, quinoline-2, pyridine-4, pyridine-2, and benzothiazole-2 have been carried out using the quantum mechanical PCILO (perturbative configuration interaction using localized orbitals) method. These molecules may be considered as heterocyclic analogues of benzylidene anilines whose conformations have been studied extensively by both theoretical and experimental methods to explain the difference of their spectra from the isoelectronic benzylidene compounds. The results of the present studies show that the β-aza styryl dyes are nearly planar. In case of β-aza styryl dyes, although the phenyl ring is coplanar with the central atoms, there is a substantial twist of the heterocyclic ring. These results are explained in terms of CT-1 and CT-2 effects and are used as a possible explanation for the observed spectral and sensitization properties.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
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  • 6
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The kinetics of polymerization of acrylonitrile initiated by the redox system manganese (III) acetate/ethylene glycol was studied in aqueous sulfuric acid medium in the temperature range from 30 to 40°C. The effect of varying the concentrations of monomer (M), acetic acid, and sulfuric acid and the addition of some electrolytes on the rate of polymerization (Rp) was investigated. Based on the experimental observations of the dependence of (Rp) on various parameters, a suitable kinetic scheme could be proposed. The plot of Rp2[M]2 vs. [M] was found to be linear, a striking general phenomenon observed for all the substrates we have studied in this laboratory.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 47-51 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In this investigation an approach to correlate the composite rate constants of some redox polymerization reactions [acrylonitrile-Ce(IV)-organic substrate] with a new type of multiparameter equation is described. The multiparameter equation is based on Swain and Lupton's F and R, the field and resonance components of the substituents, respectively, and the unique positional weighting factors f and r suggested by Williams and Norrington. The statistical parameters of the correlation involving the substituent constants (fF and rR) and the rate data have been found to be quite satisfactory, the average coefficient of determination being 0.91. The significance levels of the correlation also indicate that the present model is applicable to the kinetics of redox polymerization. The sign and magnitude of the reaction-dependent regression constants α and β suggest that three different types of reaction mechanisms are operative for the substrates benzaldehyde, phenylthiourea, acetophenone, and toluene.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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