Substituent effect on ring proton chemical shifts in PMR spectra of monosubstituted pyridines

1989 ◽  
Vol 25 (11) ◽  
pp. 1272-1275 ◽  
Author(s):  
O. P. Shkurko ◽  
A. Yu. Denisov ◽  
V. P. Mamaev
Keyword(s):  
Substituent Effect ◽  
Chemical Shifts ◽  
Ring Proton ◽  
Pmr Spectra ◽  
Proton Chemical Shifts

Studies on the PMR Spectra of Oxetanes. III. 2-Methyloxetane

1971 ◽  
Vol 26 (1) ◽  
pp. 136-140 ◽  
Author(s):  
Jukka Jokisaari
Keyword(s):  
Spectral Analysis ◽  
Spin System ◽  
Chemical Shifts ◽  
Methyl Groups ◽  
Spectral Parameters ◽  
Proton Proton ◽  
Inductive Effects ◽  
Pmr Spectra ◽  
Oxetane Ring ◽  
Proton Chemical Shifts

Abstract The 60 MHz PMR sub-spectral analysis of 2-methyloxetane (A3BCDEF spin system) has been carried out approximating some weak couplings to zero. The proton chemical shifts and the proton-proton couplings are reported. Also the proton chemical shifts of symmetrically substituted 2,2-di-methyloxetane and 3,3-dimethyloxetane have been investigated. The anisotropy and inductive effects of the methyl groups, together with the evidently nonplanar structure of the oxetane ring in 2-methyloxetane, affect the spectral parameters of the protons under inspection

RING-PROTON CHEMICAL SHIFTS OF SOME SUBSTITUTED ANILINES IN CARBON TETRACHLORIDE AND TRIFLUOROACETIC ACID

1963 ◽  
Vol 41 (9) ◽  
pp. 2339-2345 ◽  
Author(s):  
W. F. Reynolds ◽  
T. Schaefer
Keyword(s):  
Carbon Tetrachloride ◽  
Steric Hindrance ◽  
Trifluoroacetic Acid ◽  
Electronic Spectra ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Amino Group ◽  
Substituted Anilines ◽  
Ring Proton ◽  
Proton Chemical Shifts

The chemical shifts of the ring-proton spectra of a series of substituted anilines are reported relative to internal benzene in the solvents carbon tetrachloride and trifluoroacetic acid. The substituent parameters in cyclohexane derived by Martin can be used together with our parameters for the para-fluoro and -ammonio (NH3+) groups to demonstrate additivity of the substituent effects in both carbon tetrachloride and trifluoroacetic acid. The somewhat puzzling ring-proton shifts in the latter solvent are attributed to counterion effects arising from a juxtaposition of the two centers of charge. Steric hindrance to π-overlap of the amino group with the ring is demonstrated in certain cases and a parallel behavior is found between the ring-proton shifts and the electronic spectra of these molecules.

scholarly journals Studies on the PMR Spectra of Oxetanes . V. 2-(3,4-Dichlorophenyl)oxetane and 2-(2,4-Dichlorophenyl)oxetane

1973 ◽  
Vol 28 (1) ◽  
pp. 30-34
Author(s):  
Jukka Jokisaari ◽  
Erkki Rahkamaa
Keyword(s):  
Magnetic Resonance ◽  
Spectral Method ◽  
Phenyl Ring ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Proton Proton ◽  
Magnetic Parameters ◽  
Pmr Spectra ◽  
The Absolute ◽  
Proton Chemical Shifts

The 60 MHz proton magnetic resonance spectra of 2-(3,4-dichlorophenyl)oxetane and 2-(2,4-dichlorophenyl)oxetane in 10 mole per cent CCl4 solution have been analyzed using the sub-spectral method. The proton chemical shifts and the proton-proton couplings have been determined. Some aspects concerning the effects of the 3- and 2-chlorines in the phenyl ring on the magnetic parameters have been put foward. The proton-proton couplings 4J0 and 5Jm from the benzyl proton to the ortho and meta protons in-the phenyl ring, respectively, were found to be opposite in sign. Comparing the absolute values of these couplings, it was concluded that the rotation around the Ph-C bond between the phenyl and oxetane rings is more hindered in 2-(2,4-dichlorophenyl)oxetane than in 2-(3,4-dichlorophenyl)oxetane.

NMR-spektroskopische Untersuchungen über zwischenmolekulare Wechselwirkungen bei Benzolderivaten und Pyrrol / NMR-Spectroscopic Investigation of the Intermolecular Reactions of Benzene Derivatives and Pyrrole

1969 ◽  
Vol 24 (11) ◽  
pp. 1365-1370 ◽  
Author(s):  
H.-H. Perkampus ◽  
U. Krüger ◽  
W. Krüger
Keyword(s):  
Dipole Moment ◽  
Temperature Dependence ◽  
Aromatic Compounds ◽  
Spectroscopic Investigation ◽  
Chemical Shifts ◽  
Benzene Derivatives ◽  
Intermolecular Reactions ◽  
Proton Chemical Shifts

The proton chemical shifts of aromatic compounds are strongly concentration dependent. Moreever, for molecules with a dipole moment a temperature dependence of the proton chemical shifts is observed. For hemellitone, p-methylanisole, o-chlortoluene, p-chlortoluene, pyrrole and N-methyl-pyrrole the enthalpies of a dipole-dipole association between -0,7 and -1,8 Kcal could be estimated by NMR measurements combined with the temperature dependence in the whole range of the molefraction (0 → 1).

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