Directory: Faculty

David M. Grant

David M. Grant

PHYSICAL CHEMISTRY

Distinguished Professor

B.S., 1954, University of Utah
Ph.D., 1957, University of Utah

Phone: (801) 581-8854

Office: 1320 HEB-N

Email: grant@chem.utah.edu

Research Group

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Research Interests

Professor Grant's research interests are in the area of nuclear magnetic resonance with special emphasis on the carbon-13 magnetic isotope. For many years, his group has correlated chemical shifts with the electronic and geometrical structure of molecules. Quantum mechanical calculations of these parameters using both semi-empirical and more sophisticated wave functions provide a theoretical basis for the correlations.

Recent activity in the laboratory has been focused on the NMR of organic solids. Using cross polarization techniques, solid carbon-13 data can be obtained under magic-angle spinning conditions and on stationary samples. Relatively high-resolution solid spectra are obtained which contain information not only on intramolecular but also intermolecular features. In many systems the break in molecular symmetry, due to crystal environmental effects, is accompanied by an increase in the number of resonance lines. Solid NMR works on single crystals provides a useful relationship with X-ray crystallography results.

Single crystal samples are either impossible or unduly hard to obtain when new 2D slow turning NMR methods have been found to provide high grade tensor values in the acquisition dimension, with isotropic shifts appearing in the evolution dimension. As the chemical shift tensor contains important three-dimensional information on molecular solids, shift tensor data has high promise in future NMR studies in Chemistry.

Without rapid spinning techniques, powder patterns are obtained in solid samples. Under doubly enriched molecules in two carbon-13 isotopes yield dipolar coupled spectra from which the carbon-carbon distances can be obtained, as well as the chemical shielding tensor components. Even for a powder or matrix-isolated molecule the dipole-dipole axis fixes the orientation of these shielding tensors within an arbitrary rotation about the carbon-carbon vector.

A variety of solid applications in both fossil fuels and biomedicine have proven the value of the new techniques. Work with natural products and pharmaceutical chemicals of considerable size allow the shielding tensors to provide conformational and stereo chemical information not available in solid powder spectral patterns.

Work on instrumental development of the NMR technique in both solids and liquids is also under way. Especially important is the improvement of probes and their performance in multiple dimension NMR experiments. Recent work has led to the construction of a high pressure, variable temperature cell that can be used at 500 MHz for the study of molecules that may be dissolved in super critical fluids such as CO2 and related materials. Molecules dissolved in super critical fluids have motional regimes that lie between gases and liquids and such data allow for continuity between these states of matter.

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