ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Chemistry  (5)
Collection
Keywords
Publisher
Years
  • 1
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemistry of Substituted Cycloheptatrienes. XV. About the Characterization of the Electronic Transitions in 1-Aryl-4-(p-dimethylaminophenyl)-cycloheptatrienesThe absorption spectra of the title compounds are discussed in dependence on polarity of the solvent and its ability to form hydrogen bonds. The results suggest a hybridization of the N-atom of the dimethylamino group between sp3 and sp2 in the ground state. Contrary to this, the nitrogen has sp2-hybridization in the short wavelength (SE) fluorescing state. In a second fluorescence state the geometry of the seven-membered ring should change. Therefore the viscosity of the solvents influences both the position and the quantum yield of this long wavelength emission (LE). The influence of polarity and viscosity of the solvents is described by multiple regression. The temperature dependence of fluorescence quantum yields is discussed, as well.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 327 (1985), S. 505-515 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemistry of Substituted Cycloheptatrienes. XVII. 1-Aryl-4-(p-dimethylaminophenyl)-cycloheptatrienesThe photochemistry of the title compounds is different from that of the isomeric 1-(p-dimethylaminophenyl)-4-aryl-cycloheptatrienes. The sigmatropic 1, 7-hydrogen shift is dominant caused by the arylic substituent in position 1 of the seven-membered ring. Only strong donor substituents like the p-methoxyphenyl group in position 1 cause photovalence tautomerism.The properties of solvents influence both the quantum yields of the photoreactions and the fluorescence quantum yields. The connections between the fluorescing state and the photoreactivity are discussed. Solvent viscosity and polarity are shown to be relevant for the deactivation parameters.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemistry of Substituted Cycloheptatrienes. XII. Dual Fluorescence of 1-Aryl-4-(p-dimethylaminophenyl)-cycloheptatrienesDiarylcycloheptatrienes 1 in solution show two fluorescences originating from two different excited states. The ratio of intensities of the two fluorescences depends on the excitation energy. Two alternatives are discussed as the origin of the dual fluorescence: conformers in the ground state or an adiabatic photoreaction, respectively. The two emissions are ascribed to different geometries of the seven-membered ring. Despite the different excitation spectra the dual fluorescence of the compounds 1 is explained as an excited state property of a single absorbing species, and not as two ground state species giving rise to the two fluorescence bands.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 325 (1983), S. 95-103 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Zur Interpretation des Lösungsmitteleinflusses auf spektroskopische und photophysikalische Parameter mittels MehrparametermodellenDie Anwendung von Mehrparametermodellen nach Kamlet und Taft auf die Solvatochromie von Absorption und Fluoreszenz sowie auf photophysikalische Parameter wird durch Beispiele aus der Literatur und durch eigene Beispiele demonstriert.Dabei werden besonders spezifische Wechselwirkungen zwischen Substrat und Lösungsmittel diskutiert. Mit Hilfe der Regressionskoeffizienten von multiplen Korrelationen lassen sich Beziehungen zwischen der Struktur der Substrate und dem Ort der spezifischen Wechselwirkungen herstellen.Die Beschreibung dynamischer Prozesse gelingt mit der Einführung eines zusätzlichen Viskositätsparameters, der auf der scheinbaren Arrheniusschen Aktivierungsenergie der Lösungsmittelviskosität beruht.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 562 (1988), S. 186-192 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Use of Classification Methods to Interpret the Influence of Solvents on Parameters of EPR SpectraThe influence of solvents on EPR spectra of CuII-Acetylacetonate (registered at room temperature) was investigated. The classification of mean values of the g-tensors and coupling constants using different clustering methods lead to groups of solvents which are related to the respective substance classes. The analysis of the relationship between EPR data and solvent parameters showed, that there exists a close relation between Lewis basicity of solvents and classification found by using clustering methods.
    Notes: Es wurde der Lösungsmitteleinfluß auf die bei Zimmertemperatur aufgenommenen EPR-Spektren des CuII-Acetylacetonats untersucht. Die Klassifikation der erhaltenen Mittelwerte des g-Tensors und der Kopplungskonstante mittels verschiedener Clustermethoden führte zu einer Einteilung der Lösungsmittel, die eine weitgehende Übereinstimmung mit den Substanzklassen aufweist. Die Analyse des Zusammenhanges zwischen EPR-Daten und Lösungsmittelparametern mit Hilfe der linearen Regressionsanalyse zeigte, daß die Lewisbaseneigenschaften der Lösungsmittel mit der oben gefundenen Klasseneinteilung im Zusammenhang stehen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...