High-Resolution SEDOR and Switch Angle Sample Spinning Probes for Dipolar Recoupling

West Virginia University Research Corporation, Morgantown WV

Investigators

Abstract

The overarching goal of this proposal is the development of new techniques for structure elucidation in the solid state. The PI proposes to accomplish this by exploiting dipolar couplings between nuclear spins. The strength of these couplings correlates with interatomic distances and thus provides structural information that is otherwise only accessible by diffraction techniques. The advantages of using nuclear magnetic resonance (NMR) over diffraction lie in the fact that single crystals are not required, and that the method is very sensitive to protons which are usually invisible in X-ray diffraction experiments. The PI pioneered this technique for nuclei with nuclear spin of 1/2 (such as H, C, F, P). In this proposal, the PI seeks to expand this technique to quadrupolar nuclei with a spin greater or equal than 1. In fact, most of the elements in the periodic table possess magnetically active isotopes only with quadrupolar spin. Many of these are extremely important for biological samples (Na, O) or materials research (Li, Cs, V, etc.) The PI proposes the design and construction of new NMR probes and their implementation in a series of new NMR experiments to achieve this goal. Structure elucidation is one of the central questions in chemistry. The understanding of molecular structure helps to deduce relationships with molecular function. This knowledge is crucial for the development of new materials that enhance the quality of our lives or allow for the creation of new drugs. Structure elucidation of materials in their solid state using diffraction techniques usually requires the material to be present in their crystalline, or well-ordered, form. However, especially biological materials are often difficult to crystallize and thus tools like nuclear magnetic resonance (NMR) spectrocopy have been developed to aid in structure elucidation. NMR spectroscopy has other limitations, however, such as a much lower sensitivity, and generally, the inaccessibility of elements whose nuclei suffer from a non-spherical charge distribution. The majority of elements in the periodic table falls into this category, and includes elements of high biological relevance such as oxygen and sodium. The latter are inaccessible to atomic distance measurements by solid state NMR. Professor Gullion from West Virginia University plans to design, develop and build new instruments that will allow NMR measurements on these ubiquitous and important elements. Professor Gullion will engage the help of undergraduate, graduate, and postdoctoral students in this endeavor. He will share his technical know-how via video clips disseminated over the web, and free workshops in his laboratory. He will continue to entice our youngest generation about science through magic shows performed at the kindergarten level.