Results 221 to 230 of about 18,999 (260)
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A comparison of substituent effects on vicinal proton–proton and carbon–proton coupling constants
Canadian Journal of Chemistry, 1977Vicinal carbon–proton coupling constants have been determined for a series of tert-butyl derivatives and compared to the vicinal proton–proton coupling constants in the analogous series of isopropyl derivatives. In both series coupling constants were found to decrease with electronegativity of substituent, with 3JC,H decreasing more rapidly than 3JH,H.
T. P. Forrest, S. Sukumar
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Protonation constants of ?-alanine in electrolyte mixtures at constant ionic strength
Journal of Solution Chemistry, 1995The stoichiometric acid-base equilibrium constants for α-alanine in tetraethylamonium iodide-potassium nitrate solutions were determined at a constant ionic strength of 1.4 m at 25°C. The results obtained are discussed on the basis of the Friedman and the Pitzer model for electrolyte mixtures.
I. Brandariz +2 more
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Vicinal NMR Proton−Proton Coupling Constants. An NBO Analysis
The Journal of Physical Chemistry A, 2001A method of natural bond orbital (NBO) interactions between bonds and antibonds, σm → , has been developed for analyzing vicinal proton−proton coupling constants, 3JHH.
Angel L. Esteban +8 more
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The effect of substituents on geminal proton–proton coupling constants. III
Canadian Journal of Chemistry, 1977The effect of substituents at the 3-position in a series of N-methyl 5,6-dihydro-7H,12H-di-benzo[c,f]azocines on the geminal coupling constants of the C-12 methylene protons has been determined. The slope of the Hammett plot of 2J vs. σ has been found to be +0.20.
Roger N. Renaud +3 more
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Vicinal proton-proton coupling constants
Molecular Physics, 1989Ernesto Díez +4 more
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Additivity relation for the proton-proton coupling constants of trisubstituted benzenes
Journal of Molecular Structure, 1972Abstract The NMR proton spectra of 12 trisubstituted benzenes in different solvents have been accurately analyzed. The proton-proton coupling constants are calculated by using an additivity relation from the data for benzene and the monosubstituted benzenes.
D.G. De Kowalewski +2 more
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The effect of substituents on geminal proton-proton coupling constants.
2009The proton magnetic resonance spectra of a series of 2-alkoxytetrahydropyrans of general formula have been measured. R represents a variety of groups, including para-, meta-, and ortho-substituted phenyl, and several alkyl substituents. The geminal coupling constant, JAB, has been determined in each ether, from the AB pattern produced by the ...
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Vicinal proton-proton coupling constants
Molecular Physics, 1994Jesús San-Fabián +7 more
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Geminal Proton-Proton Coupling Constant
The Journal of Chemical Physics, 1965P. Loève, L. Salem
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Proton Coupling Constants in Cyclobutanone
The Journal of Chemical Physics, 1966L. L. Combs, L. K. Runnels
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