Interpretation of the Carbon-13 Nuclear Magnetic Resonance Relaxation Time Data by the Computer-Assisted Method of Analysis: Application to Strychnine in Solution

Abstract

Nuclear magnetic resonance relaxation times of carbons including quaternary ones have been measured for strychnine in CDCl₃ at 11.74T. A computer-assisted method of analysis has been applied to interpret the data based on the three models of molecular reorientational motion. The contribution of dipole-dipole relaxation is estimated for the quaternary carbons in the method of analysis without invoking a separate time-consuming measurement of nuclear Overhauser effect factors; this enables us to discuss the mechanism of relaxation in these carbons. The dipolar part is dominant for the quaternary sp³ carbon, whereas contributions other than the Bipolar part are also significant for the quaternary sp² carbons.