Nuclear magnetic resonance studies of the bonding in aromatic systems. Correlation of Hammett sigma constants with methyl13C-H coupling constants and chemical shifts

1969 ◽  
Vol 91 (3) ◽  
pp. 539-543 ◽  
Author(s):  
Claude H. Yoder ◽  
Richard H. Tuck ◽  
Ronald E. Hess
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Magnetic Resonance Studies ◽  
Aromatic Systems ◽  
Nuclear Magnetic

Studies of specifically fluorinated carbohydrates. Part I. Nuclear magnetic resonance studies of hexopyranosyl fluoride derivatives

1969 ◽  
Vol 47 (1) ◽  
pp. 1-17 ◽  
Author(s):  
L. D. Hall ◽  
J. F. Manville ◽  
N. S. Bhacca
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Angular Dependence ◽  
Chemical Shifts ◽  
Relative Orientation ◽  
Coupling Constants ◽  
Pyranose Ring ◽  
Spectral Parameters ◽  
Magnetic Resonance Studies ◽  
Nuclear Magnetic

A detailed study has been made of both the 1H and 19F nuclear magnetic resonance (n.m.r.) spectra of a series of hexopyranosyl fluoride derivatives. Some of the 1H spectra were measured at 220 MHz. The 1H spectral parameters define both the configuration and the conformation of each of these derivatives. Study of the 19F n.m.r. parameters revealed several stereospecific dependencies. The 19F chemical shifts depend upon, (a) the orientation of the fluorine substituent with respect to the pyranose ring and, (b) the relative orientation of other substituents attached to the ring; for acetoxy substituents, these configurational dependencies appear to be additive. The vicinal19F–1H coupling constants exhibit a marked angular dependence for which Jtrans = ca. 24 Hz whilst Jgauche = 1.0 to 1.5 Hz for [Formula: see text] and 7.5 to 12.6 Hz for [Formula: see text] The geminal19F–1H couplings depend on the orientation of the substituent at C-2; when this substituent is equatorial JF,H is ca. 53.5 Hz and when it is axial the value is ca. 49 Hz.

Studies of specifically fluorinated carbohydrates. Part II. Nuclear magnetic resonance studies of pentopyranosyl fluoride derivatives

1969 ◽  
Vol 47 (1) ◽  
pp. 19-30 ◽  
Author(s):  
L. D. Hall ◽  
J. F. Manville
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Resonance Spectroscopy ◽  
Magnetic Resonance Studies ◽  
Conformational Model ◽  
Nuclear Magnetic

Detailed studies, by 1H and 19F nuclear magnetic resonance spectroscopy, of a series of fully esterified pentopyranosyl fluorides, show that all such derivatives favor that conformer in which the fluorine substituent is axially oriented. This conclusion is supported by separate considerations of the vicinal and geminal19F–1H and 1H–1H coupling constants, of the long-range (4J) 1H–1H and 19F–1H coupling constants and of the 19F chemical shifts. The limitations of the above conformational model are discussed.

Nuclear Magnetic Resonance Studies on Fluorides of Trivalent Phosphorus

1965 ◽  
Vol 20 (2) ◽  
pp. 104-109 ◽  
Author(s):  
G. S. Reddy ◽  
R. Schmutzler
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Trivalent Phosphorus ◽  
Magnetic Resonance Studies ◽  
Regular Change ◽  
Nuclear Magnetic Resonance Spectra ◽  
Multiple Substitution ◽  
Nuclear Magnetic

The P31, F19, and H1 nuclear magnetic resonance spectra of a new series of compounds of the types (RO)nPF3-n and (R2N)nPF3-n (n = 1,2) have been studied. A regular change in the chemical shifts and coupling constants has been observed with multiple substitution. The changes in the coupling constants have been explained on the basis of the electronegativity of the atoms attached to phosphorus. Some long-range coupling constants between hydrogen and fluorine separated by five bonds were observed.

Nuclear magnetic resonance studies. XI. Vinyl proton chemical shifts and coupling constants of some substituted styrenes

1967 ◽  
Vol 45 (7) ◽  
pp. 731-737 ◽  
Author(s):  
Gurudata ◽  
J. B. Stothers ◽  
J. D. Talman
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Spin Systems ◽  
Coupling Constants ◽  
Vinyl Proton ◽  
Magnetic Resonance Studies ◽  
Vinyl Carbon ◽  
Proton Chemical Shifts ◽  
Nuclear Magnetic

The proton spectra of the vinyl groups in a series of 23 substituted styrenes have been analyzed as ABC spin systems. The proton chemical shifts are compared with the previously reported shielding data for the corresponding vinyl carbon nuclei. The series includes 12 meta- and para-substituted examples and 10 ortho-substituted examples. The effects of steric inhibition of conjugation on the vinyl proton parameters for some 2,6-disubstituted derivatives are considered in detail.

31P and 19F Nuclear Magnetic Resonance Studies of Phosphorus-Fluorine Compounds

1970 ◽  
Vol 25 (11) ◽  
pp. 1199-1214 ◽  
Author(s):  
G. S. Reddy ◽  
R. Schmutzler
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Coordination Number ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Magnetic Resonance Studies ◽  
Nuclear Magnetic Resonance Spectra ◽  
Fluorine Compounds ◽  
Nuclear Magnetic

The nuclear magnetic resonance spectra (31P, 19F) of a variety of compounds containing phosphorus-fluorine bonds have been studied, in continuation of earlier investigations on the same type of compounds.The previously observed relationship between coordination number of phosphorus and δP was generally confirmed, i. e. δP becomes more positive as the coordination number around phosphorus increases. No meaningful substitution rules, either for chemical shifts or for P-F coupling constants, could be established. The data obtained are discussed qualitatively in relation to the electronegativity of the substituents and to the coordination number of phosphorus. Data on the preparation and characterization of numerous phosphorus-fluorine compounds are also included.

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