Proton relaxation NMR study of polycrystalline progesterone
Andrew E. R.1, Jurga K.1, Radomski J. M.1, Reynhardt E. C.1
- 1Departments of Physics and Radiology, University of Florida, Gainesville, FL 32611, United States
Solid State Nuclear Magnetic Resonance, 1 (3), pp.121-125, 1992
DOI:: 10.1016/0926-2040(92)90012-X
Abstract:
Polycrystalline progesterone (4-pregnene-3,20-dione, C21H30O2) has been investigated by proton NMR methods between 80 and 350 K. A reduction in dipolar second moment is ascribed to methyl group reorientation. Minima in the spin-lattice relaxation time found in measurements at five frequencies from 7 to 200 MHz are attributed to reorientation of two of the three methyl groups in each molecule, characterized by activation energy Ea = 10.9 ± 0.8 kJ/mol and τ0 = (2.3 ± 0.2) × 10-13, s. Additional relaxation at lower temperatures is attributed to reorientation of the third methyl group with Ea approximately 3.4 kJ/mol. Measurements were also made of relaxation in the rotating frame. © 1992.
full version of publicationshow all publications