Andrew E R, Jurga K, Radomski J M, Reynhardt E C
Department of Physics, University of Florida, Gainesville, 32611.
Solid State Nucl Magn Reson. 1992 Jul;1(3):121-5. doi: 10.1016/0926-2040(92)90012-x.
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 tau o = (2.3 +/- 0.2) x 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.
采用质子核磁共振方法在80至350K温度范围内对多晶型孕酮（4-孕烯-3,20-二酮，C21H30O2）进行了研究。偶极第二矩的降低归因于甲基的重新取向。在7至200MHz五个频率下测量发现的自旋晶格弛豫时间最小值，归因于每个分子中三个甲基中的两个甲基的重新取向，其特征在于活化能Ea = 10.9 +/- 0.8 kJ/mol以及弛豫时间常数tau o = (2.3 +/- 0.2) x 10(-13) s。较低温度下的额外弛豫归因于第三个甲基的重新取向，其活化能约为3.4 kJ/mol。还进行了旋转坐标系中的弛豫测量。
