PROTON MAGNETIC RESONANCE ABSORPTION IN ETHYL STEARATE

1963 ◽  
Vol 41 (2) ◽  
pp. 378-381 ◽  
Author(s):  
R. F. Grant ◽  
D. Llewelyn Williams
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Relaxation Times ◽  
Resonance Absorption ◽  
Crystal Defects ◽  
Ethyl Stearate ◽  
Spin Lattice ◽  
Β Phase ◽  
Α Phase ◽  
Resonance Relaxation

The proton magnetic resonance absorption in ethyl stearate has been investigated at −77, 0, and 24 °C in the solid β-phase and at 28 °C in the solid α-phase. Spin-lattice proton magnetic resonance relaxation times were measured in the liquid up to 75 °C and in the solid α-phase. The results suggest that the α-phase is composed partly of molecules in a liquid-like state and partly of molecules constrained to rotate about their longitudinal axes. The results also support the proposal that the dielectric dispersion observed in the β-phase is due to molecular motion in crystal defects.

A proton magnetic resonance relaxation study of molecular motions in trimethylamine-borane

1976 ◽  
Vol 54 (7) ◽  
pp. 1087-1091 ◽  
Author(s):  
T. T. Ang ◽  
B. A. Dunell
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Solid Phase ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Free Induction ◽  
Resonance Spin ◽  
Resonance Relaxation

Proton magnetic resonance spin–lattice relaxation times T1 have been measured for trimethylamine-borane from 120 to 380 K, a few degrees above the melting point. Minima in T1 at 157 and 259 K are attributed to threefold reorientation of each of the three methyl groups and the borane group and to threefold reorientation of the whole molecule about the B—N axis, respectively. Activation energies for these processes were found to be 3.3 and 6.7 kcal/mol. Abrupt changes in T1 at 350 and 360 K correspond exactly with heat capacity transitions observed by other workers. The time constant for the decay of the free induction signal (FID curve) changes by two orders of magnitude at 360 K. Having a value of some 3 ms above 360 K, it shows that there must be rapid diffusion as well as molecular tumbling in the highest temperature solid phase.

A proton magnetic resonance relaxation time study of several vitamin D derivatives

1980 ◽  
Vol 58 (1) ◽  
pp. 45-50 ◽  
Author(s):  
George Kotowycz ◽  
Tom T. Nakashima ◽  
M. Kirk Green ◽  
Gerdy H. M. Aarts
Keyword(s):  
Vitamin D ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Relaxation Times ◽  
Biologically Active ◽  
Resonance Relaxation ◽  
S Application ◽  
Calculated Distance ◽  
Spectral Assignment

Proton magnetic resonance relaxation time studies at 200 and 400 MHz have been measured for vitamins D2, D3, as well as the biologically active 1α,25-(OH)2D3. A comparison of these relaxation times at the two frequencies allows the evaluation of the dipolar correlation times for the different protons in the molecule. These are very short, and range from < 0.7 × 10−10 s to 1.2 × 10−10 s. Application of the Solomon equation to the relaxation times of the 19Z and 19E protons allows a calculation of the internuclear distance since these two geminal protons relax each other predominantly by the dipolar mechanism. Using the T1 values, the calculated distances are 1.98 ± 0.10 Å for 1α,25-(OH)2D3, 2.01 ± 0.10 Å for D3, and 1.95 ± 0.10 Å for D2. The calculated distance based on a neutron diffraction distance for the C—H bond is 1.91 Å. The measurement of the relaxation times also allows a definitive spectral assignment of the 21- and 28-methyl protons for vitamin D2.

Phase Transformation and Structure of N-chlorocarbonylisocyanide Dichloride

1998 ◽  
Vol 53 (6-7) ◽  
pp. 546-548 ◽  
Author(s):  
Evgenii A. Romanenko
Keyword(s):  
Dipole Moments ◽  
Relaxation Times ◽  
Spin Lattice ◽  
Β Phase ◽  
Α Phase ◽  
Level Data ◽  
Temperature Dependences ◽  
Ir Frequencies ◽  
Polymorphic Forms ◽  
Nuclear Quadrupole

Abstract The 35Cl nuclear quadrupole resonances in N-chlorocarbonylisocyanide dichloride show that it exists in two polymorphic forms. The metastable a phase has six 35Cl NQR lines and the stable β phase has three. The latter is obtained irreversibly by annealing the α phase at 179 K. The temperature dependences of the 35Cl NQR frequencies, spin-lattice and spin-spin relaxation times are obtained in both phases. The results of the 35Cl NQR studies are discussed together with calculated MNDO level data and other physical properties (IR frequencies, dipole moments) of this compound.

scholarly journals Water Content and Proton Magnetic Resonance Relaxation Times of the Brain in Newborn Rabbits

1998 ◽  
Vol 43 (3) ◽  
pp. 421-425 ◽  
Author(s):  
Ervin Berényi ◽  
Imre Repa ◽  
Péter Bogner ◽  
Tamás Dóczi ◽  
Endre Sulyok
Keyword(s):  
Magnetic Resonance ◽  
Water Content ◽  
Proton Magnetic Resonance ◽  
Relaxation Times ◽  
Resonance Relaxation ◽  
The Brain

Developmental Changes in Proton Magnetic Resonance Relaxation Times of Cardiac and Skeletal Muscle

1988 ◽  
Vol 23 (4) ◽  
pp. 289-293 ◽  
Author(s):  
RUTHELLEN FRIED ◽  
FERENC A. JOLESZ ◽  
ANTONIO V. LORENZO ◽  
HOWARD FRANCIS ◽  
DOUGLASS F. ADAMS
Keyword(s):  
Skeletal Muscle ◽  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Relaxation Times ◽  
Developmental Changes ◽  
Resonance Relaxation

scholarly journals МINIMIZATION OF EXPERIMENT ERRORS IN THE METHOD OF PMR AND OPPORTUNITIES FOR RECEIVING OF RELAXATION TIMES SPECTRA

2019 ◽  
Vol 20 (11-12) ◽  
pp. 152-160 ◽  
Author(s):  
Р. S. Кashaev ◽  
А. Yu. Svinin ◽  
О. V. Коzelkov
Keyword(s):  
Magnetic Resonance ◽  
Spin Relaxation ◽  
Laplace Transformation ◽  
Proton Magnetic Resonance ◽  
Spin Echo ◽  
Kinetic Curve ◽  
Relaxation Times ◽  
Resonance Relaxation ◽  
Measurements Errors ◽  
Minimization Of Errors

Made an appreciation of measurements errors in method of proton magnetic resonance relaxation (PMRR) for receiving of values of spin-spin relaxation times Т2i and corresponding them values А2i, of relative amplitudes of spin-echo envelope. Estimatesof opportunities of reverse Laplace transformation (L-1) algorithm realized in UpenWin program for relaxation times spectra determination, minimization of errors and facilitation for interpretation received data of kinetic curve PMRR relaxation process.

Proton Magnetic Resonance Relaxation Times and Biomechanical Properties of Human Vascular Wall

1992 ◽  
Vol 27 (7) ◽  
pp. 510-513 ◽  
Author(s):  
PHILIPPE VIN??E ◽  
BERNARD MEURER ◽  
ANDR?? CONSTANTINESCO ◽  
BERND KOHLBERGER ◽  
KARLHEINZ HAUENSTEIN ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Relaxation Times ◽  
Vascular Wall ◽  
Biomechanical Properties ◽  
Resonance Relaxation

Proton Magnetic Resonance Relaxation Times T1 and T2 Related to Postmortem Interval

1986 ◽  
Vol 27 (1) ◽  
pp. 115-118 ◽  
Author(s):  
Z. Györffy-Wagner ◽  
E. Englund ◽  
E.-M. Larsson ◽  
A. Brun ◽  
S. Cronqvist ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Relaxation Times ◽  
Postmortem Interval ◽  
T1 And T2 ◽  
Resonance Relaxation
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