Methyl-Driven Overhauser Dynamic Nuclear Polarization
The Overhauser effect is unique among DNP mechanisms in that it requires the modulation of the electron–nuclear hyperfine interactions. While it dominates DNP in liquids and metals, where unpaired electrons are highly mobile, Overhauser DNP is possible in insulating solids if rapid structural modula...
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Published in | The journal of physical chemistry letters Vol. 13; no. 18; pp. 4000 - 4006 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
12.05.2022
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Subjects | |
Online Access | Get full text |
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Summary: | The Overhauser effect is unique among DNP mechanisms in that it requires the modulation of the electron–nuclear hyperfine interactions. While it dominates DNP in liquids and metals, where unpaired electrons are highly mobile, Overhauser DNP is possible in insulating solids if rapid structural modulations are linked to a modulation in hyperfine coupling. Herein, we report that Overhauser DNP can be triggered by the strategic addition of a methyl group, demonstrated here in a Blatter’s radical. The rotation of the methyl group leads to a modulation of the hyperfine coupling to its protons, which in turn facilitates electron–nuclear cross-relaxation. Removal of the methyl protons, through deuteration, quenches the process, as does the reduction of the hyperfine coupling strength. This result suggests the possibility for the design of tailor-made Overhauser DNP polarizing agents for high-field MAS-DNP. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 USDOE Office of Science (SC), Basic Energy Sciences (BES) AC02-07CH11358 IS-J 10,800 |
ISSN: | 1948-7185 1948-7185 |
DOI: | 10.1021/acs.jpclett.2c00748 |