scholarly journals The Chemical Shift of the 29Si Nuclear Magnetic Resonance in a Synthetic Single Crystal of Mg2SiO4

1985 ◽  
Vol 40 (2) ◽  
pp. 126-130 ◽  
Author(s):  
N. Weiden ◽  
H. Rager
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Single Crystal ◽  
Angular Dependence ◽  
Room Temperature ◽  
Bond Distance ◽  
Chemical Shift Tensor ◽  
The Individual ◽  
Nuclear Magnetic

The angular dependence of the chemical shift of the 29Si nuclear magnetic resonance has been measured in a synthetic single crystal of Mg2SiO4 (space group Pbnm, Z = 4). The measurements were performed at room temperature at a frequency of 39.758 MHz using the FT-NMR technique. The eigenvalues of the shift tensor with respect to 29Si in TMS are δx = - 38.8 ppm, δv = -55.3 ppm and δz = - 95.4 ppm, with the eigenvector y parallel to c and the eigenvector z forming an angle of 7.5° with a. The results show clearly the influence of the individual S i - O bonds on the chemical shift tensor. The chemical shift along the S i -O bond depends in good approximation exponentially on the S i - O bond distance.

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.

NUCLEAR MAGNETIC RESONANCE STUDIES: IX. THE CHEMICAL SHIFT OF THE FORMYL PROTON IN ALIPHATIC ALDEHYDES

1966 ◽  
Vol 44 (1) ◽  
pp. 45-51 ◽  
Author(s):  
R. E. Klinck ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Aliphatic Aldehydes ◽  
Magnetic Resonance Studies ◽  
Unsaturated Aldehydes ◽  
Potential Use ◽  
Nuclear Magnetic

The effects of structure on the shielding of formyl protons of aliphatic aldehydes have been examined. The survey included examples of acyclic, alicyclic, and α, β-unsaturated aldehydes. The potential use of these results as an aid for structural elucidations is discussed, and the limitations are noted.

Sign in / Sign up

Export Citation Format

Share Document