This proposal is focused on the synthesis of new molecules, polymers and gels to be used with dynamic nuclear polarization (DNP) to produce enhanced NMR signals. The PI has a continuing collaboration with Professor Robert G. Griffin of the Francis Bitter Magnet Laboratory for critical evaluation of DNP materials and DNP NMR applications. The DNP method makes use of spins associated with radicals to polarize the nuclear spins of the molecules of interest. Preliminary investigations with biradicals have shown that these molecules provide greatly enhanced signals in NMR spectra (observed enhancements of H 300 are obtained in magic angle spinning spectra of solids and H 400 in solution NMR spectra). The coupled biradical approach has allowed these high enhancements at lower concentrations than can be achieved with a mono-radical species. The lower concentrations minimize the broadening due to the paramagnetic radicals in the mixture. New improved biradicals and next generation polyradical-based fullerene structures will be synthesized and evaluated for their ability to polarize nuclear spins. Extended polyradical structures based upon polymers will be developed and evaluated for DNP activity. These latter materials will be converted into gels for the polarization of liquids and eventually DNP NMR structure studies. Anisotropic DNP gels will be produced and offer new opportunities for NMR structure determination. This research is directed at producing materials that will lead to improved analysis of the structures of biological molecules by nuclear magnetic resonance and eventually novel imaging techniques for MRI. Magnetic resonance methods suffer from low sensitivity and dynamic nuclear polarization addresses this limitation. In this process electrons are excited by microwaves and transfer magnetic polarization to nuclei to produce large sensitivity enhancements.

Public Health Relevance

This research is directed at producing materials that will lead to improved analysis of the structures of biological molecules by nuclear magnetic resonance and novel imaging techniques for MRI. Magnetic resonance methods suffer from low sensitivity and dynamic nuclear polarization addresses this limitation. In this process electrons are excited by microwaves and transfer magnetic polarization to nuclei to produce large sensitivity enhancements.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM095843-03
Application #
8432066
Study Section
Synthetic and Biological Chemistry A Study Section (SBCA)
Program Officer
Wehrle, Janna P
Project Start
2011-03-01
Project End
2015-02-28
Budget Start
2013-03-01
Budget End
2014-02-28
Support Year
3
Fiscal Year
2013
Total Cost
$307,186
Indirect Cost
$114,186
Name
Massachusetts Institute of Technology
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
001425594
City
Cambridge
State
MA
Country
United States
Zip Code
02139
Can, T V; Caporini, M A; Mentink-Vigier, F et al. (2014) Overhauser effects in insulating solids. J Chem Phys 141:064202
Zhao, Yanchuan; Markopoulos, Georgios; Swager, Timothy M (2014) ¹?F NMR fingerprints: identification of neutral organic compounds in a molecular container. J Am Chem Soc 136:10683-90
Kiesewetter, Matthew K; Michaelis, Vladimir K; Walish, Joseph J et al. (2014) High field dynamic nuclear polarization NMR with surfactant sheltered biradicals. J Phys Chem B 118:1825-30
Ong, Ta-Chung; Mak-Jurkauskas, Melody L; Walish, Joseph J et al. (2013) Solvent-free dynamic nuclear polarization of amorphous and crystalline ortho-terphenyl. J Phys Chem B 117:3040-6
Frantz, Derik K; Walish, Joseph J; Swager, Timothy M (2013) Synthesis and properties of the 5,10,15-trimesityltruxen-5-yl radical. Org Lett 15:4782-5
Michaelis, Vladimir K; Smith, Albert A; Corzilius, Bjorn et al. (2013) High-field 13C dynamic nuclear polarization with a radical mixture. J Am Chem Soc 135:2935-8
Dane, Eric L; Corzilius, Björn; Rizzato, Egon et al. (2012) Rigid orthogonal bis-TEMPO biradicals with improved solubility for dynamic nuclear polarization. J Org Chem 77:1789-97
Kiesewetter, Matthew K; Corzilius, Bjorn; Smith, Albert A et al. (2012) Dynamic nuclear polarization with a water-soluble rigid biradical. J Am Chem Soc 134:4537-40
Andrew, Trisha L; Swager, Timothy M (2011) Thermally-Polymerized Rylene Nanoparticles. Macromolecules 44:2276-2281