MOLECULAR AND STRUCTURAL INFORMATION FROM VARIABLE-ANGLE SPINNING NMR DIPOLAR SPECTRA OF C-13-N-14 SYSTEMS

A sample-spinning solid-state NMR study of a spin- 1 2 nucleus coupled to a quadrupolar nucleus is presented. Using a simple approach, the quadrupolar effect is expanded in terms of irreducible spherical tensor components up to l = 4. Information on the electric field gradient tensor orientation, dipolar coupling, and chemical-shielding tensor for the 13C-14N system can be obtained experimentally from the magic-angle and the off-magic-angle sample-spinning spectra. Satisfactory results are obtained by comparing the simulations with the experimental spectra of tetramethylpyrazine, dimethylglyoxime, and triethylenediamine. © 1990.