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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 65 (1961), S. 2268-2269 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 66 (1962), S. 573-574 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical chemistry accounts 14 (1969), S. 80-90 
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Um die Elektronenstruktur von protonisierten N-Heterozyklen zu untersuchen, wurden SCF-MO-Rechnungen durchgeführt, bei denen die Polarisierung der σ-Bindung durch die Ladung am N-Atom berücksichtigt wird. Eine geeignete Parametrisierung der Valenzzustands-Energien in Verbindung mit dem Modell der Polarisierung der σ-Bindung wird vorgeschlagen. Die Rechnungen zeigen, da\ ein herkömmliches kovalentes Modell für die genannten Verbindungen bei der ErklÄrung des Elektronenspektrums versagt, wÄhrend ein Modell mit stark polarisierten σ-Bindungen befriedigende Ergebnisse liefert. Aus der vorliegenden Theorie lÄ\t sich folgern, da\ das Elektronenspektrum des Chinolins betrÄchtlich durch die Polarisierung der σ-Bindung infolge Protonisierung geÄndert wird.
    Abstract: Résumé Afin d'éclaircir la structure électronique d'hétérocycles protonisés sur l'azote, nous avons effectué des calcules SCF MO en considérant la polarization des liaisons σ dûe à la forte charge nette sur l'atome d'azote. Des paramétrisations appropriées à ce modèle polarisé sont proposées pour les énergies des états de valence. Nos calculs ont montré qu'un modèle covalent conventionnel pour les N hétérocycles protonisés ne réussit pas à expliquer le spectre électronique expérimental alors qu'un modèle à forte polarisation du squelette σ donne des résultats dans l'ensemble satisfaisants. Cette théorie prévoit que la nature du spectre électronique de la quinoléine est considérablement modifiée par la polarisation σ dûe à la protonisation.
    Notes: Abstract In order to elucidate the electronic structure of protonated N-heterocycles, we have carried out SCF MO calculations, considering the σ-bond polarizations which are caused by the large net charge on nitrogen atom. Appropriate parametrizations of the valence state energies associated with the σ-bond polarization model have been proposed. Our calculations showed that a conventional covalent model for protonated N-heterocycles failed to explain the experimental electronic spectral data and an extremely polarized σ-core model gave quite good results in the whole. The present theory expected that the nature of electronic spectra of quinoline is considerably changed by the σ-bond polarization due to the protonation.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-8927
    Keywords: Molar excess enthalpy ; enthalpy of transfer ; water ; aqueous ; 1-methyl-2-pyrrolidinone ; normal alcohol ; branched alcohol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Molar excess enthalpies were measured for 1-methyl-2-pyrrolidinone mixed with various pure alcohols and with aqueous alcohols at a low mole fraction of 1-methyl-2-pyrrolidinone at 298°K, using a LKB flow microcalorimeter. Enthalpies of transfer of 1-methyl-2-pyrrolidinone from water to the aqueous alcohol mixtures are estimated from the molar excess enthalpies. The results are discussed from the point of view of the effect of 1-methyl-2-pyrrolidinone on the structure of aqueous alcohol solutions.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1572-8927
    Keywords: Molar excess enthalpy ; enthalpy of transfer ; aqueous ; 1-methyl-2-pyrrolidinone ; methanol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Molar excess enthalpies were measured for 1-methyl-2-pyrrolidinone mixed with water and with methanol over the whole concentration range and with aqueous methanol at the low mole fraction of 1-methyl-2-pyrrolidinone at 298.15°K, using a LKB flow microcalorimeter. Enthalpies of transfer of 1-methyl-2-pyrrolidinone from water to aqueous methanol were estimated from the molar excess enthalpies. The result was qualitatively in agreement with the conclusion described by Arnett et al.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 2175-2181 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The interaction between DNA and dyes such as acridine orange (1), proflavine (2), and 3,8-diamino-5-ethyl-6-phenylphenanthridinium bromide (3) were studied by means of the heat of mixing and UV spectra. From the results obtained, the thermodynamic quantities of DNA-dye complexes were estimated. It is concluded that the intercalation process forms a more stable binding than the stacking process does. Further, in each process, ΔG of DNA-2 and DNA-3 systems is nearly equal to that of the DNA-1 system, but their  -  ΔH and  -  ΔS values are higher than those of the DNA-1 system. The stability of binding in DNA-2 and DNA-3 systems may be governed largely by ΔH, while in the DNA-1 system ΔS may contribute largely to the stability of binding.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 2837-2843 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The interaction between poly(A) · poly(U) duplex and dyes (proflavine (PF) and 9-aminoacridine (9-AA)) was studied by means of the heat of mixing. From the results, thermodynamic quantities of poly(A) · poly(U) duplex-dye systems for the intercalation process were estimated. The free energy change for the poly(A) · poly(U) duplex-(PF) system is smaller than that for the poly(A) · poly(U) duplex-(9-AA) system, indicating that PF intercalated into poly(A) · poly(U) duplex is more stable than the intercalated 9-AA. This conclusion is based on the absolute value of the heat of interaction between PF and poly(A) · poly(U) duplex being larger than that between 9-AA and the poly(A) · poly(U) duplex.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 105 (1967), S. 154-163 
    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: Die Verdünnungswärme wäßriger Lösungen von Polyäthylenglykol wurde mit einem Mikrozwillings-Kalorimeter bei 25°C gemessen. Die Polymerisationsgrade der verwendeten Polymeren waren 2, 5, 15, 25, 100, 500, 2500 und 15,000.Zur Analyse der experimentell ermittelten Daten wurde die einfache, sowie eine modifizierte VAN LAAR-Gleichung verwendet. Die Wechselwirkungsparameter zwischen Polymeren und Lösungsmittel wurden berechnet.Es ergab sich, daß die Wechselwirkungsparameter nicht nur von den Konzentrationen, sondern auch von den Molekulargewichten der Polymeren abhängig sind und daß sie qualitativ mit der Theorie verdünnter Polymerlösungen übereinstimmen.
    Notes: The heats of dilution of poly(ethylene oxide)/water solutions were measured by use of a micro twin calorimeter at 25°C. The degrees of polymerization of the polymers were 2, 5, 15, 25, 100, 500, 2500, and 15,000.For the analysis of the experimental data, the simple VAN LAAR formula has been used, together with a modified one; so the interaction parameters between the polymer and the solvent have been derived.It was found that the interaction parameters are considerably dependent not only on the concentration, but also on the molecular weight of the polymer, and that they correspond qualitatively with the theory of dilute polymer solutions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 3425-3431 
    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: Verdünnungsenthalpien für Poly(1-vinyl-2-pyrrolidon), (Poly[1-(2-oxopyrrolidin-1-yl)-ethylene]), in wäßrigen Methanollösungen von unterschiedlichem Methanolgehalt, wurden bei 298 K gemessen. Das Molekulargewicht des Polymeren betrug 10000 bzw. 40000.Die experimentellen Ergebnisse wurden nach einer modifizierten Tompa-Gleichung mit konzentrationsabhängigem Wechselwirkungsparameter analysiert und so der Wechselwirkungsparameter zwischen dem Polymeren und dem Mischlösungsmittel für unendliche Verdünnung erhalten.Der Einfluß von Methanol auf die Wechselwirkung zwischen dem Polymeren und Wasser wurde aufgrund der Änderungen des Wechselwirkungsparameters bei unendlicher Verdünnung für die Überführung des Polymeren von Wasser in wäßriges Methanol diskutiert.
    Notes: Enthalpies of dilution of poly(1-vinyl-2-pyrrolidone), (poly[1-(2-oxopyrrolidin-1-yl)ethylene]), in aqueous methanol solutions of different methanol contents were measured at 298 K. The molecular weight of the polymer was 10000 and 40000, respectively.The experimental results were analysed with a modified Tompa formula containing an interaction parameter dependent on concentration; so the interaction parameter at infinite dilution between the polymer and the mixed solvent was derived.The influence of methanol on the interaction between polymer and water molecules was discussed from the change of the interaction parameter at infinite dilution for the transfer process from water to aqueous methanol solvent.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 1439-1444 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The heats of dilution of atactic polystyrene-anisole, -dibenzyl ether, and -acetophenone systems were measured in the concentration range of 0,168 to 0,02 in volume fraction of the polymer, by adding successively 1 ml of the solvent to the solution of a known concentration by using an isothermal calorimeter at 303K. The heats of dilution of all systems obtained proved to be exothermic.The interaction heat parameter depends considerably on the concentration of the polymer and also on the molecular weight of the polymer. In polystyrene-anisole and -dibenzyl ether systems an interesting fact was found: the χ1-parameter is negative and its absolute value increases at first, reaches a maximum and then decreases as the molecular weight of the polymer increases.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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