Fluorine magnetic resonance studies. VII. Fluorine-fluorine coupling over five bonds in 1-Fluoro-2-(2'-fluorophenyl)ethanes

1984 ◽  
Vol 37 (8) ◽  
pp. 1769 ◽  
Author(s):  
DA Burgess ◽  
MF Finn ◽  
D Jordan ◽  
ID Rae ◽  
D Walters
Keyword(s):  
Magnetic Resonance ◽  
Diels Alder ◽  
Spin Coupling ◽  
Side Chain ◽  
Magnetic Resonance Studies ◽  
Close Proximity ◽  
New Compounds ◽  
Spin Spin Coupling ◽  
Alder Adduct

Spin-spin coupling between an aromatic fluorine and fluorines in an adjacent side chain (Ar-C-C-F), with J values in the range 2-5 Hz, is reported for four new compounds. The coupling probably arises from through-space interactions taking place when rotation of the side chain brings the two types of fluorine into close proximity. In a Diels-Alder adduct of fluoranil and 1-fluoro-4-methyl- anthracene, this proximity is denied the fluorines and no coupling is observed.

Through-space or proximate 19F,19F and 19F,1H spin–spin coupling constants in some benzenesulfonyl fluoride derivatives

1976 ◽  
Vol 54 (22) ◽  
pp. 3564-3568 ◽  
Author(s):  
William J. E. Parr ◽  
Ted Schaefer
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Side Chain ◽  
Conformational Preference ◽  
Fluorine Nucleus ◽  
Spin Coupling Constants ◽  
The Difference ◽  
Spin Spin Coupling

The analysis of the fluorine and proton magnetic resonance spectra of 2,4,6-trimethylbenzenesulfonyl fluoride and of 2,5-difluorobenzenesulfonyl fluoride yields the signs and magnitudes of the spin–spin coupling constants containing a through-space component. The coupling between the fluorine nucleus and the methyl protons over five bonds is +1.9 Hz, opposite in sign to the −3.1 Hz observed for the corresponding coupling in 2,6-dimethylbenzoyl fluoride. The difference of 5 Hz is possibly a consequence of the different conformational preference of the SO2F and COF substituents. The coupling over four bonds between the fluorine nucleus on the side chain and that on the ring is +11.6 Hz in 2,5-difluorobenzenesulfonyl fluoride. It is argued that this value indicates a preference of the S—F bond for a plane lying, on average, nearly perpendicular to the benzene ring. Similar indications are noted for pentafluorobenzenesulfonyl fluoride and for pentafluorobenzenesulfinyl fluoride.

Fluorine magnetic resonance studies. I. para-Substituted β,β-difluorostyrenes

1972 ◽  
Vol 25 (7) ◽  
pp. 1465 ◽  
Author(s):  
ID Rae ◽  
LK Smith
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Spin Coupling ◽  
Coupling Constant ◽  
Lower Field ◽  
Magnetic Resonance Studies ◽  
Fluorine Compounds ◽  
Spin Spin Coupling ◽  
Magnetic Resonance Spectra

A series of seven para-substituted β,β-difluorostyrenes has been prepared and their proton and fluorine magnetic resonance spectra recorded. The fluorine spectra show interesting correlations with the σ- values for the para substituents, the fluorine resonances moving to lower field and the geminal fluorine-fluorine coupling constant decreasing as σ- increases. These trends parallel those observed in the analogous styrenes but rather more precise relationships have been established for the fluorine compounds. Long range fluorine-fluorine spin-spin coupling over six and seven bonds, respectively, has been observed in the β,β,β,3- and β,β,4-trifluoro-styrenes.

An estimate of the spin–spin coupling constant, 1J(1H,13C), in gaseous benzene

1996 ◽  
Vol 74 (8) ◽  
pp. 1524-1525 ◽  
Author(s):  
Ted Schaefer ◽  
Guy M. Bernard ◽  
Frank E. Hruska
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Dielectric Constant ◽  
Magnetic Resonance ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Coupling Constant ◽  
Spin Coupling Constant ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Gaseous Benzene

An excellent linear correlation (r = 0.9999) exists between the spin–spin coupling constants 1J(1H,13C), in benzene dissolved in four solvents (R. Laatikainen et al. J. Am. Chem. Soc. 117, 11006 (1995)) and Ando's solvation dielectric function, ε/(ε – 1). The solvents are cyclohexane, carbon disulfide, pyridine, and acetone. 1J(1H,13C)for gaseous benzene is predicted to be 156.99(2) Hz at 300 K. Key words: spin–spin coupling constants, 1J(1H,13C) for benzene in the vapor phase; spin–spin coupling constants, solvent dielectric constant dependence of 1J(1H,13C) in benzene; benzene, estimate of 1J(1H,13C) in the vapor; nuclear magnetic resonance, estimate of 1J(1H,13C) in gaseous benzene.

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