33S NMR Spectroscopy. 2. Substituent Effects on33S Chemical Shifts and Nuclear Quadrupole Coupling Constants in 3- and 4-Substituted Benzenesulfonates. Correlation between Chemical Shifts and Nuclear Quadrupole Coupling Constants†

1997 ◽  
Vol 62 (26) ◽  
pp. 9031-9033 ◽  
Author(s):  
Roberta Musio ◽  
Oronzo Sciacovelli
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Coupling Constants ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

Structure et réactivité des benzoxazoles: étude par résonance magnétique nucléaire du carbone-13

1979 ◽  
Vol 57 (8) ◽  
pp. 937-945 ◽  
Author(s):  
Jeanine Llinares ◽  
Jean-Pierre Galy ◽  
Robert Faure ◽  
Emile-Jean Vincent ◽  
José Elguero
Keyword(s):  
Nmr Spectroscopy ◽  
Empirical Model ◽  
Chemical Shifts ◽  
Structural Parameters ◽  
Substituent Effects ◽  
Coupling Constants ◽  
Prototropic Tautomerism ◽  
Résonance Magnétique ◽  
C Nmr

Thirty-four benzoxazoles, oxazole, and 10 o-aminophenols have been studied by 13C nmr spectroscopy. All the signals have been attributed from substituent effects. The structure of products obtained by nitration of benzoxazole have been determined by 13C nmr. The shifts induced by substitution at the 2 position have been discussed as a function of an empirical model using the structural parameters F, R, and Q*. Azido–tetrazole equilibria (N3 in position 2) and prototropic tautomerism (NH2, OH, and SH in position 2) have been also discussed. The chemical shifts and coupling constants of oxazole and unsubstituted benzoxazole have been compared.

19F Nuclear Quadrupole Coupling in some Halomethanes

1986 ◽  
Vol 41 (1-2) ◽  
pp. 171-174 ◽  
Author(s):  
M. Frank ◽  
F. Gubitz ◽  
W. Ittner ◽  
W. Kreische ◽  
A. Labahn ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Simple Model ◽  
Temperature Dependence ◽  
Coupling Constants ◽  
Temperature Dependent ◽  
Distribution Method ◽  
Quadrupole Coupling ◽  
Time Differential ◽  
Nuclear Quadrupole

The 19F quadrupole coupling constants in CF4, CHF3, CClF3 and CHClF2 are reported. The measurements were carried out temperature dependent using the time differential perturbed angular distribution method (TDPAD). The temperature dependence can be satisfactorily described in the framework of the Bayer-Kushida theory. A simple model is used to explain the appearance of H-F and Cl-F coupling constants in CHF3/CHClF2 and CClF3, respectively.

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