PROTON MAGNETIC RESONANCE SPECTRUM OF 1-PHENYLCYCLOPROPYLCARBOXYLIC ACID: A2B2 SPECTRA OF CYCLOPROPANES

1963 ◽  
Vol 41 (10) ◽  
pp. 2429-2438 ◽  
Author(s):  
H. M. Hutton ◽  
T. Schaefer
Keyword(s):  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Carbon Disulphide ◽  
Proton Magnetic Resonance Spectrum ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Saturated Ring ◽  
Geminal Coupling ◽  
Range Of Values ◽  
Qualitative Discussion

A2B2 spectra of 1,1 -disubstituted cyclopropanes have been calculated over a range of values of the spectral parameters. The sign of the geminal coupling is opposite to that of the vicinal couplings. Since this is also the case with other saturated ring systems the theoretical spectra should be useful in studies of other saturated ring systems.The shifts and coupling constants are given for the protons in 1-phenylcyclopropylcarboxylic acid in solution in carbon disulphide, chloroform, and benzene as an example of the A2B2 analysis. The ring protons in 1-phenylcyclopropylcarbinol were found to be equivalent in different solvents, with insignificant coupling to the protons in the methylene and phenyl groups. A qualitative discussion of the shifts of the various protons in various solvents is given.

SOLVENT EFFECTS AS AN AID IN THE ANALYSIS OF THE PROTON MAGNETIC RESONANCE SPECTRUM OF VINYL BROMIDE

1960 ◽  
Vol 38 (11) ◽  
pp. 2066-2073 ◽  
Author(s):  
T. Schaefer ◽  
W. G. Schneider
Keyword(s):  
Chemical Shift ◽  
Solvent Effects ◽  
Resonance Spectrum ◽  
Proton Magnetic Resonance Spectrum ◽  
Coupling Constants ◽  
Vinyl Bromide ◽  
Proton Coupling ◽  
Geminal Proton ◽  
Geminal Coupling ◽  
Cis And Trans

By making use of specific solvent effects it has been possible to vary the relative chemical shift between the geminal protons of vinyl bromide from about +10 cycles/sec to −4 cycles/sec (at 60 Mc/sec) and to study the resultant changes in the proton resonance spectrum in the limiting region of zero chemical shift. Of particular interest is the growth and displacement of the combination lines, which appear in the resonance signals of the proton bonded to the same carbon atom as the bromine. From the variation of the six possible lines in this region it was confirmed that the cis and trans proton coupling constants must have the same sign. The intensity distribution of the lines in the geminal proton region require the geminal coupling constant to be of opposite sign to the other two.

Das Protonenresonanzspektrum von orientiertem Benzol in nematisch-kristallinflüssiger Lösung

1965 ◽  
Vol 20 (4) ◽  
pp. 572-580 ◽  
Author(s):  
Alfred Saupe
Keyword(s):  
Magnetic Resonance ◽  
Chemical Shift ◽  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Proton Magnetic Resonance Spectrum ◽  
Coupling Constants ◽  
Scalar Coupling ◽  
Small Temperature ◽  
Theoretical Methods ◽  
Experimental Errors

The proton magnetic resonance spectrum of benzene oriented in a nematic solution is calculated using group theoretical methods. The calculations agree within experimental errors with the spectrum of benzene observed in a nematic solution of 4.4′-di-n-hexyloxy-azoxy-benzene. By an improvement of the temperature homogenity in the sample it was possible to obtain linewidths of only about 5 cps for all lines independent of the splitting. It is confirmed that the signs of the scalar coupling constants between ortho and meta protonpairs are positive. A small temperature dependence of the chemical shift of the benzene protons was found in the nematic solution. It is due to the dependence of the average orientation on the temperature.

Conformational dependence of long-range spin-spin coupling constants in 2,6-dichlorobenzylfluoride

1969 ◽  
Vol 47 (19) ◽  
pp. 3688-3690 ◽  
Author(s):  
T. Schaefer ◽  
C. M. Wong ◽  
K. C. Tam
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Double Resonance ◽  
Proton Magnetic Resonance Spectrum ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Double resonance experiments on the proton magnetic resonance spectrum of 2,6-dichlorobenzylfluoride yield the signs of the long-range coupling constants between the ring protons and the fluorine nuclei and protons in the fluoromethyl group. The signs and magnitudes of the long-range couplings are discussed in terms of their dependence on the conformation of the fluoromethyl group.

scholarly journals Proton Magnetic Resonance Spectrum of 2-Chloroaniline-15N. Long-range Coupling Constants to Amino Protons from all Ring Protons

1971 ◽  
Vol 49 (22) ◽  
pp. 3627-3635 ◽  
Author(s):  
R. Wasylishen ◽  
T. Schaefer
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Proton Magnetic Resonance Spectrum ◽  
Proton Exchange ◽  
Coupling Constants ◽  
Amino Group ◽  
Fast Rotation ◽  
The One

The p.m.r. spectra of 2-chloroaniline and 2-chloroaniline-15N in benzene and toluene solutions are analyzed at 60 and 100 MHz under conditions where the amino protons are exchanging intermolecularly and also where they are not exchanging. The spectrum of 2-chloroaniline-H15ND in the absence of amino proton exchange is observed between −48 and 80 °C. In all situations fast rotation about the C—N bond evidently occurs. Long-range couplings of the amino protons to all ring protons are observed and their signs are determined. The nonplanarity of the amino group is discussed in terms of the long-range couplings, of the one-bond 15N–H couplings, and of the two-bond H–H couplings in the amino group. The signs and magnitudes of the coupling constants between the ring protons and 15N are also determined.

THE PROTON MAGNETIC RESONANCE SPECTRUM OF CYCLOPROPYLAMINE, THE A2A2′X CASE WITH STRONG CROSS-COUPLING: A PSEUDO FIRST-ORDER SPECTRUM WITH COMBINATION LINES

1963 ◽  
Vol 41 (11) ◽  
pp. 2774-2780 ◽  
Author(s):  
H. M. Hutton ◽  
T. Schaefer
Keyword(s):  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Cross Coupling ◽  
Proton Magnetic Resonance Spectrum ◽  
Coupling Constants ◽  
Proton Spectrum ◽  
First Order ◽  
Order Spectrum ◽  
Complete Set ◽  
Pseudo First Order

By means of the anisotropic solvent effect of benzene on the ring protons of cyclopropylamine the proton spectrum is converted to A2A2′X. Since the cross-coupling from the A2 to the A2′ protons is large the spectrum does not approximate to a pseudo first-order AX4 spectrum. Instead, it is one which may be described as pseudo first-order with combination lines. The presence of the latter allows a fairly complete set of coupling constants to be derived in a simpler way than by a computer attack on the general A2B2X spectrum. Conversely, the approach developed here, when applicable, allows the derivation of reliable input parameters for a computer program. From the temperature dependence of the A2A2′X case the A2 and A2′ protons can be distinguished and it is found that the protons trans to the amino group are preferentially shifted to high field by the benzene molecules.

The Proton Magnetic Resonance Spectrum of p-Methylbenzylbromide, Conformational Preference of the Bromomethyl Rotor

1974 ◽  
Vol 52 (20) ◽  
pp. 3489-3494 ◽  
Author(s):  
Kalvin Chum ◽  
J. Brian Rowbotham ◽  
Ted Schaefer
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Alternative Model ◽  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Proton Magnetic Resonance Spectrum ◽  
Coupling Constants ◽  
The Other ◽  
Complete Analysis ◽  
Conformational Preference

A complete analysis is given of the nine-spinproton magnetic resonance spectrum of p-methylbenzyl bromide as a 20 mol% solution in acetone-d6 The long-range coupling constants between methyl and ring protons are the same as those in toluene. The coupling constants between the methylene protons and the other protons in the molecule are consistent with a two-fold barrier of 500 ± 200 cal/mol for the bromomethyl group, the preferred conformation having the C—Br bond in a plane perpendicular to the aromatic plane. An alternative model, in which a C—H bond of the bromomethyl rotor prefers the aromatic plane to the extent of 3 kcal/mol, is considered unlikely.

Proton Magnetic Resonance Spectrum of Parafluorotoluene. Sigma and Pi Electron Contributions to JpH,F

1971 ◽  
Vol 49 (1) ◽  
pp. 94-101 ◽  
Author(s):  
R. Wasylishen ◽  
T. Schaefer
Keyword(s):  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Proton Magnetic Resonance Spectrum ◽  
Pyridine Derivatives ◽  
Proton Resonance ◽  
Spectral Parameters ◽  
Fluorine Nucleus ◽  
Proton Proton ◽  
Methyl Proton ◽  
Electron Contribution

The p.m.r. spectrum of a 15 mole % solution of p-fluorotoluene in acetone-d6 is analyzed at 100 MHz using LAOCN3 and LAME computer programs. The resulting spectral parameters satisfactorily reproduce the methyl proton resonance at 60 MHz. The coupling over six bonds between the fluorine nucleus and the methyl protons is 1.15 ± 0.02 Hz and is taken as a measure of the π electron contribution to the coupling over five bonds between the fluorine nucleus and the proton in p-fluorobenzene. The σ electron contribution to this coupling is discussed for some fluorobenzene derivatives and is shown to depend on the electronegativity of the substituents in a manner completely analogous to proton–proton and other proton–fluorine couplings in benzene and pyridine derivatives.

Proton magnetic resonance spectrum of 4-pyrone, chromone and xanthone

1966 ◽  
Vol 22 (7) ◽  
pp. 1391
Author(s):  
Caroline T. Mathis ◽  
J.H. Goldstein
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Proton Magnetic Resonance Spectrum
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