Molecular motion and methyl group rotation barriers from 13C nmr relaxation times. Podacarpic acid derivatives

1982 ◽  
Vol 60 (10) ◽  
pp. 1173-1177 ◽  
Author(s):  
Helmut Beierbeck ◽  
John W. Easton ◽  
John K. Saunders ◽  
Russell A. Bell
Keyword(s):  
Diffusion Tensor ◽  
Rotational Diffusion ◽  
Relaxation Times ◽  
Nmr Relaxation ◽  
Time Data ◽  
Nmr Relaxation Times ◽  
Group Rotation ◽  
Rotational Diffusion Tensor ◽  
Nmr Relaxation Time ◽  
C Nmr

The 13C nmr relaxation time data for a number of compounds related to podocarpic acid are presented. The T1 values of these molecules were satisfactorily reproduced by application of Woessner's equations for an asymmetric top assuming that the preferred principal axis of the rotational diffusion tensor was either the preferred principal inertial axis or an axis containing the centre of mass and the heterosubstituent at C-4. The values for hindrance to rotation for the various methyl groups are given and their variations discussed.

Molecular motion and methyl group rotation barriers from 13C nmr relaxation times. Norbornane and adamantane derivatives in solution

1980 ◽  
Vol 58 (2) ◽  
pp. 102-109 ◽  
Author(s):  
Helmut Beierbeck ◽  
Robert Martino ◽  
John K. Saunders
Keyword(s):  
Relaxation Time ◽  
Diffusion Tensor ◽  
Rotational Diffusion ◽  
Relaxation Times ◽  
Nmr Relaxation ◽  
Adamantane Derivatives ◽  
Time Data ◽  
Methyl Group ◽  
Group Rotation ◽  
Methyl Group Rotation

The carbon-13 relaxation time data for several norbornane and adamantane derivatives are presented. It is shown that the most probable principal axis of the rotational diffusion tensor is an axis which contains the centre of mass of the molecule and the heterosubstituent. The influence of the C—Ĉ—H bond angle on the calculation of methyl group rotation barriers from relaxation time data and on the barrier is discussed.

scholarly journals Proton NMR relaxation times in ischemic brain edema.

Stroke ◽  
1986 ◽  
Vol 17 (6) ◽  
pp. 1149-1152 ◽  
Author(s):  
Y Horikawa ◽  
S Naruse ◽  
C Tanaka ◽  
K Hirakawa ◽  
H Nishikawa
Keyword(s):  
Brain Edema ◽  
Relaxation Times ◽  
Proton Nmr ◽  
Nmr Relaxation ◽  
Ischemic Brain ◽  
Ischemic Brain Edema ◽  
Nmr Relaxation Times

Effects of hydrophobic treatments of stone on pore water studied by continuous distribution analysis of NMR relaxation times

2001 ◽  
Vol 19 (3-4) ◽  
pp. 509-512 ◽  
Author(s):  
L. Appolonia ◽  
G.C. Borgia ◽  
V. Bortolotti ◽  
R.J.S. Brown ◽  
P. Fantazzini ◽  
...  
Keyword(s):  
Pore Water ◽  
Relaxation Times ◽  
Continuous Distribution ◽  
Nmr Relaxation ◽  
Distribution Analysis ◽  
Nmr Relaxation Times

Reduction in the proton NMR relaxation times of dystrophic muscles following functional improvement

1984 ◽  
Vol 2 (3) ◽  
pp. 250-251 ◽  
Author(s):  
L.K. Misra ◽  
P.A. Narayana ◽  
D. Bearden ◽  
T. Egan ◽  
R.P. Munjaal ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Proton Nmr ◽  
Nmr Relaxation ◽  
Functional Improvement ◽  
Nmr Relaxation Times
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