¹³C and ¹H NMR Relaxation of Chloroform Dissolved in a Nematic Liquid Crystal. I. Cross Correlation between Intramolecular and Intermolecular Dipole-Dipole Interactions

抄録

¹³C and ¹H relaxation times of a coupled ¹³C–¹H spin system dissolved in a nematic phase have been measured at 400 MHz (for ¹H) by the selective and nonselective inversion recovery method. The relaxation times of doublet lines of each spin are different from each other. Especially, when a ¹H line is inverted selectively, the relaxation time of the ¹³C line connected progressively to the inverted one is fairly different depending on which line of the ¹H is inverted. Master equations for longitudinal relaxation are derived under the assumption that in addition to two relaxation mechanisms of the intramolecular dipole-dipole and external random field interactions, interference effects between the two might be nonnegligible in the oriented phase. The differences in the relaxation times have been explained by this interference effect.