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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The analysis of various spirits using a GC-IR-MS coupling permits the qualitative description of their constituents based on their characteristic spectra. Sample preparation, instrumentation, experimental parameters and peak identification using a combined library search are described.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 14 (1980), S. 155-156 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High field high resolution 13C NMR spectroscopy allows the quantitative determination of a mixture of the four diastereomers in racemic α-tocopherol.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 23 (1985), S. 1056-1071 
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Intelligent programs for structure elucidation should be able to predict structural features, or even complete structures, for an unknown compound. This can be accomplished by substructure analysis of the topological matrices corresponding to the most similar reference spectra detected by a library search. A comparison of the results from different spectroscopic techniques (1H NMR, 13C NMR, IR, MS) reflects the content of the individual data bases, and also the sensitivity of the specific physical experiment to structural changes. The results can be combined to yield multidimensional information on the probability of any given substructure, even without crosslinked libraries from varying sources. In connection with the structure generator and the 13C NMR spectrum estimation in ACCESS, a prediction of novel structures is routinely possible, as exemplified by the analysis of the spectra of 3′-methylacetophenone and genipin. The great advantages of this approach lie in its high flexibility in omitting or adding information and the absence of hand-encoded rules, because knowledge of the system simply stems from its experience, i.e. the structure-oriented spectral data bases.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 91 (1969), S. 6189-6190 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 93 (1971), S. 4472-4479 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 1 (1969), S. 435-449 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The substituent effect on proton resonances and vicinal H, H-coupling constants in benzene derivatives is studied using linear regression analysis. The change in shielding observed on substitution, relative to the proton resonance in benzene, Δσ, can be expressed as \documentclass{article}\pagestyle{empty}\begin{document}$$ \Delta\sigma = - 1.04 \times 10^{- 12} {\rm E}_{\rm Z} - 1.08 \times 10^{- 18} {\rm E}^{\rm 2} + 9.17\Delta \rho + 0.18. $$\end{document}. This equation enables calculations of substituent effects on the basis of the dipolar and quadratic field effect (Ez, E2) and the π-charge density changes on the neighbouring C-atom (Δρ).The vicinal coupling constants show no correlation with the HMO-π-bond order. A linear regression using the well known dependence of the coupling constant on substituent electronegativity yields \documentclass{article}\pagestyle{empty}\begin{document}$$ ^3 {\rm J = 7}{\rm .63 + 0}{\rm .508}\Delta \alpha - 0.096\Delta \beta $$\end{document} where ΔEα and ΔEβ are the changes in electronegativity caused by substitution in α- or β-position, respectively, to the HCCH-fragment considered.
    Notes: Der Einfluß von Substituenten auf die Protonenresonanzen und die vicinalen H, H-Kopplungskonstanten in Benzolderivaten wird mit Hilfe linearer Ausgleichsrechnungen untersucht. Für die relativ zur Protonenresonanz des Benzols auftretende Abschirmungsänderung Δσ bei der Substitution wird die Beziehung \documentclass{article}\pagestyle{empty}\begin{document}$$ \Delta\sigma = - 1.04 \times 10^{- 12} {\rm E}_{\rm Z} - 1,08 \times 10^{- 18} {\rm E}^{\rm 2} + 9,17\Delta \rho + 0,18. $$\end{document} angegeben, die eine Berechnung der Substituenten-Effektes mit Hilfe des dipolaren und quadratischen Feldeffektes (Ez, E2) und der π-Ladungsdichte-Änderung am benachbarten C-Atom (Δρ) erlaubt.Die vicinalen Kopplungskonstanten lassen sich mit der HMO-π-Bindungsordnung nicht korrelieren. Eine Ausgleichsrechnung unter Benutzung der bekannten Abhängigkeit der Kopplung von der Substituenten-Elektronegativität liefert \documentclass{article}\pagestyle{empty}\begin{document}$$ ^3 {\rm J = 7}{\rm .63 + 0}{\rm .508}\Delta \alpha - 0.096\Delta \beta $$\end{document} wobei ΔEα und ΔEβ die durch Substitution bedingte Änderung der Elektronegativität in α- bzw. β-Stellung zum betrachteten HCCH-Fragment bedeuten.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0570-0833
    Keywords: Artificial intelligence ; Computer chemistry ; Spectroscopy ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The difference between the older and the more recent computer systems amounts, in the final analysis, to the difference between an insect and a human being. The insect comes “fully programmed” into the world-programmed by instincts which it follows without using any thought processes. On the other hand, the human being must first learn the correct behavior-however, such learning can develop an impetus all its own: becoming, indeed, proceeding from his own decision and his awareness, the human being can change his former action programs. The creation of a computer system of the X-th generation will actually far more resemble educating a child than the traditional programming of a computer.
    Additional Material: 28 Ill.
    Type of Medium: Electronic Resource
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