Library

X
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
  • Methyl benzoates  (2)
  • Hindered resonance  (1)
  • Sadlej's basis set  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Improved method of calculating group polarization effects: constants σα (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 485-488 
    Details
    ISSN: 0894-3230
    Keywords: group polarization effects ; polarizability countants ; ab initio ; Sadlej's basis set ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An improved model is presented for ab initio calculations of the polarizability constants σα using Sadlej's basis set. A new set of constants was calculated for common groups and these were compared with previous 3-21G and 3-21G* calculations and with some experimental equilibrium constants in the gas phase. For the time being, the calculations seem to be the most general approach for obtaining these constants whereas the experimental possibilities are limited in scope. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Steric Effects and Steric Hindrance to Resonance in tert-Butylbenzoic Acids in the Gas Phase and in Solution (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 1589-1594 
    Details
    ISSN: 1434-193X
    Keywords: Resonance ; Hindered resonance ; Steric hindrance ; Conformation analysis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Substituent effects of the tert-butyl group in isomeric tert-butylbenzoic acids have been investigated on the basis of enthalpies of formation, gas-phase acidities, acidities in methanol and in dimethyl sulfoxide, and the IR spectra in tetrachloromethane. In contrast to 2-methylbenzoic acid, 2-tert-butylbenzoic acid must adopt a non-planar conformation, as is confirmed by its IR spectrum. Enhanced acidity in the gas phase has been found for all isomers and attributed to a pole-induced dipole interaction in the anion (polarizability effect); in the ortho isomer the steric inhibition of resonance is only responsible for a minor part of the observed effect. In solution, the electrostatic interaction is attenuated, but remains strong in the case of the ortho isomer.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Correlation of oxygen-17 substituent-induced chemical shifts: Meta- and para-substituted methyl benzoates (1992)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 30 (1992), S. 381-386 
    Details
    ISSN: 0749-1581
    Keywords: 17O NMR ; Methyl benzoates ; Substituent effects ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxygen-17 NMR spectra of 45 substituted methyl benzoates in acetonitrile were measured at natural abundance. The substituent-induced chemical shifts (SCS) of the carbonyl oxygen correlate well with the σm and σp+ substituent constants in two separate correlations for meta and para derivatives; principal component analysis (PCA) is only slightly better [particularly for the N(CH3)2 substituent]. The 17O SCS generally depend on the same factors as the 13C SCS of the β-carbon of alkenes, provided comparison is made between compounds of similar polarity. SCS of the methoxyl oxygen depend less precisely on σm or σp, with some unexplained deviations.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260300505
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Correlation of carbon-13 substituent-induced chemical shifts: Meta- and para-substituted methyl benzoates (1989)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 27 (1989), S. 585-591 
    Details
    ISSN: 0749-1581
    Keywords: Methyl benzoates ; 13C NMR ; Substituent effects ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbon-13 NMR spectra are reported for 69 substituted methyl benzoates in deuteriochloroform or in its mixture with dimethyl sulphoxide-d6. The substituent-induced chemical shifts (SCS) of the CO carbon correlate poorly with dual substituent parameters (DSP) in all possible modifications, and for meta derivatives in particular this correlation is both overpara meterized and imprecise. A much better correlation was obtained with parameters (designated Bm, Bp and Cp) derived previously by principal component analysis (PCA) from a larger set. The SCS of the CH3 carbon correlate very well with the original simple Hammett equation, and no DSP treatment is needed. The clustering of substituents is not consequential in such a large set.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260270612
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...