Molecular and structural information from14Nndash;13C dipolar couplings manifested in high resolution13C NMR spectra of solids

摘要

The dipolar coupling between14N and13C is not suppressed by magic angle sample spinning because the relatively large14N quadrupole interaction shifts the axis of quantization of the14N spins away from the direction of the applied field. The resulting13C resonance line shapes are influenced by the sign, magnitude, and asymmetry parameter of the14N quadrupole coupling tensor; the internuclear distance; the magnitude of the applied magnetic field; and the orientation of the internuclear vector in the principal axis system of the electric field gradient. It is demonstrated that one or more of these parameters can be determined from the13C NMR data if the others are known by virtue of single crystal studies or molecular symmetry.