This research project involves the development of experimental methods for detecting less receptive nuclei (13C, 15N and 2H) with special emphasis placed on 13C. The application of such methods to biologically important systems and their theoretical consequences are stressed. The value of chemical shifts in structure correlations of liquid samples has been very well documented and these concepts are to be expanded to the full shielding tensor. The three dimensional aspects of shielding tensors becomes one of the significant aspects of the proposal. Solid state work on either powders or single crystals is required to obtain the tensoral shieldings and their principal orientations in the molecular frame. The dipolar interactions, which average to zero in isotropic liquid, also is readily studied in the solid state and its inverse cubic distance dependance contributes valuable structural information. The relaxation of 13C spin multiplets in CH and CH2 groups provides information on molecular diffusional reorientation and these methods are priving to be beneficial in the study of segmental motion in flexible carbon chains. Measurement of deuterium resonance intensities provides a powerful, new method for studying biosynthetic pathway in biologically important systems. Site-specific 2H/1H ratios provide information on not only kinetic isotope effects but retain such historical events locked into the molecular structure for time periods corresponding to the molecules stability. Work will be directed towards the development of single crystal methods for biomolecules of a size not here-to-fore possible. Finally, the development of a high speed link from the spectrometer to a VAX computer is envisioned as a way to store larger (8 M words) free induction signals with a significant improvement in the quality of two dimensional, 2D, spectra. This development aids both our solid and liquid work. The use of 2D methods in NMR have significantly advanced the use of NMR methods in biomedical fields.
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