Proton NMR study of molecular motion in solid cortisone
Authors:
- E.R. Andrew,
- Marek Kempka
Abstract
Polycrystalline cortisone (17,21-dihydroxy-4-pregnene-3,11,20-trione, C21H28O5) has been investigated by proton NMR methods between 56 and 400 K at 14 and 25 MHz. Reductions in second moment and two very well-resolved minima in the spin-lattice relaxation time at both frequencies are attributed to reorientation of the two methyl groups on carbons 18 and 19. The data are very well fitted over the entire temperature range to the Kubo-Tomita dipolar relaxation theory using the same parameters at both frequencies. Activation energies Ea characterizing the hindrances to the two methyl reorientations were 5.9 and 15.5 kJ/mol, an unusually large difference. The relaxation constants were 6.4 and 7.9 × 108 s-2. © 1993.
- Record ID
- UAMe45a0123840b4385bf7cdb1696adfd26
- Author
- Journal series
- Solid State Nuclear Magnetic Resonance, ISSN 0926-2040
- Issue year
- 1993
- Vol
- 2
- Pages
- 261-264
- ASJC Classification
- ; ; ;
- DOI
- DOI:10.1016/0926-2040(93)90006-9 opening in a new tab
- Language
- en English
- Score (nominal)
- 25
- Score source
- journalList
- Publication indicators
- = 15.000; : 1999 = 0.742; : 2006 = 1.532 (2) - 2007=1.604 (5)
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- Uniform Resource Identifier
- https://researchportal.amu.edu.pl/info/article/UAMe45a0123840b4385bf7cdb1696adfd26/
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perishopening in a new tab system.
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