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  • 1
    Electronic Resource
    Electronic Resource
    Boron atom reactions with silicon and germanium tetrahalides (1988)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 92 (1988), S. 4658-4662 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100327a020
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  • 2
    Electronic Resource
    Electronic Resource
    Boron atom reactions with the halomethanes (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 5595-5601 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Rate constants have been measured for the reactions of boron atoms with a series of halomethanes. The experiments were performed in a linear flow tube apparatus at 300 K. The measured rate constants in units of cm3 molecule−1 s−1 are CCl4:9.5×10−11; CCl3H:4.8×10−11; CCl2H2:6.2×10−11; CClH3:1.4×10−11; CCl3F:3.1×10−11; CCl2F2:5.5×10−12; CClF3:1.7×10−13; CF4:〈3×10−14; CF3H:〈2×10−14. The reaction of boron with all the chloromethanes is facile. The chlorofluoromethanes present a more complex pattern. Noteworthy is the low reactivity of the channel to produce BF, furthermore, the presence of fluorine in the halomethanes reduces the reactivity at the chlorine site. Semiempirical MNDO calculations were performed on the reacting systems. These calculations suggest possible explanations for the observed results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.449683
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  • 3
    Electronic Resource
    Electronic Resource
    Two-bond deuterium isotope effects on 13C chemical shifts. A measure of carbon—carbon bond lengths (1989)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 27 (1989), S. 253-257 
    Details
    ISSN: 0749-1581
    Keywords: Two-bond deuterium-induced isotope effects ; Neutral π systems ; 6,6-Dimethylfulvene ; Carbon-Carbon bond length ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two-bond deuterium-induced isotope effects (2Δ) have been studied in several neutral π-systems (6,6-dimethylfulvene, cyclohexene and cyclohexa-1,3-diene). Isotope effects on the 13C shifts of adjacent carbons are invariably to higher field, and vary from -84 to -139 ppb. In combination with literature data for a number of aromatic systems, these results establish that, for fragments of the type D—C(sp2)—13C(sp2) in five- or six-membered rings, 2Δ correlates linearly with carbon—carbon bond length, the average deviation between calculated and experimental bond lengths being 0.01 Å. The correlation embraces bridgehead and non-bridgehead carbons in both five- and six-membered rings. As a test of the utility of this empirical relationship, 2Δ in ferrocene-d was determined to be -91 ppb, corresponding to a carbon—carbon bond length of 1.42 Å, in good agreement with the experimental value of 1.43 Å.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260270312
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  • 4
    Electronic Resource
    Electronic Resource
    1H and 13C spectra of fluorine-containing polycyclic aromatic hydrocarbons. 1H—19F and 13C—19F coupling across bay regions (1989)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 27 (1989), S. 13-20 
    Details
    ISSN: 0749-1581
    Keywords: 1H NMR ; 13C NMR ; Fluorine-containing polycyclic aromatic hydrocarbons ; Anomalous F-induced shifts and couplings ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1H and 13C NMR spectra of several fluorine-substituted polycyclic aromatic hydrocarbons in which fluorine projects into a bay region were studied. Both protons and carbons of the sterically opposed CH bond show anomalously large F-induced shifts and couplings to fluorine. The magnitudes of the couplings (particularly the four-bond CF couplings which average 26 Hz) indicate a large through-space contribution due to direct overlap between fluorine and CH bond orbitals, whereas the F-induced shifts seem more likely to stem from diamagnetic anisotropy rather than F-induced CH bond polarization.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260270104
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  • 5
    Electronic Resource
    Electronic Resource
    13C NMR spectra of 7-, 8-, 9- and 10-fluorobenzo[a]pyrene (1986)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 24 (1986), S. 287-291 
    Details
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 13C NMR spectra of 7-, 8-, 9- and 10-fluoro-benzo[a]pyrenes have been recorded and the chemical shifts of all protonated (and fluorine-substituted) carbons have been assigned. The effect of fluorine on carbon shifts (and also on electron densities, which correlate reasonably well with the shifts) is confined largely to the fluorinated ring and contiguous sites, such as peri positions or carbons across bay regions. A variety of short- and long-range couplings are observed, and correlations with π-bond orders (two-bond couplings) and ato n polarizabilities (one-bond couplings) are observed. Long-range coupling patterns are less obvious, but six-bond couplings appear to correlate with atom-atom polarizabilities, as expected for transfer of spin information through the π-system.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260240404
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