| Relaxation times and line widths of isotopically-substituted nitroxides in aqueous solution at X-band. | |
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MedLine Citation:
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PMID: 21843961 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Optimization of nitroxides as probes for EPR imaging requires detailed understanding of spectral properties. Spin lattice relaxation times, spin packet line widths, nuclear hyperfine splitting, and overall lineshapes were characterized for six low molecular weight nitroxides in dilute deoxygenated aqueous solution at X-band. The nitroxides included 6-member, unsaturated 5-member, or saturated 5-member rings, most of which were isotopically labeled. The spectra are near the fast tumbling limit with T(1)∼T(2) in the range of 0.50-1.1 μs at ambient temperature. Both spin-lattice relaxation T(1) and spin-spin relaxation T(2) are longer for (15)N- than for (14)N-nitroxides. The dominant contributions to T(1) are modulation of nitrogen hyperfine anisotropy and spin rotation. Dependence of T(1) on nitrogen nuclear spin state m(I) was observed for both (14)N and (15)N. Unresolved hydrogen/deuterium hyperfine couplings dominate overall line widths. Lineshapes were simulated by including all nuclear hyperfine couplings and spin packet line widths that agreed with values obtained by electron spin echo. Line widths and relaxation times are predicted to be about the same at 250 MHz as at X-band. |
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Authors:
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Joshua R Biller; Virginia Meyer; Hanan Elajaili; Gerald M Rosen; Joseph P Y Kao; Sandra S Eaton; Gareth R Eaton |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2011-07-29 |
Journal Detail:
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Title: Journal of magnetic resonance (San Diego, Calif. : 1997) Volume: 212 ISSN: 1096-0856 ISO Abbreviation: J. Magn. Reson. Publication Date: 2011 Oct |
Date Detail:
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Created Date: 2011-09-29 Completed Date: 2012-01-23 Revised Date: 2013-05-23 |
Medline Journal Info:
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Nlm Unique ID: 9707935 Medline TA: J Magn Reson Country: United States |
Other Details:
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Languages: eng Pagination: 370-7 Citation Subset: IM |
Copyright Information:
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Copyright © 2011 Elsevier Inc. All rights reserved. |
Affiliation:
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Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Anisotropy Deuterium Electron Spin Resonance Spectroscopy / methods Indicators and Reagents Isotope Labeling Nitrogen Isotopes Nitrogen Oxides / chemistry* Nitrogen Radioisotopes Solutions Spin Labels Water / chemistry |
| Grant Support | |
ID/Acronym/Agency:
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EB000557/EB/NIBIB NIH HHS; EB002807/EB/NIBIB NIH HHS; P41 EB002034/EB/NIBIB NIH HHS; P41 EB002034-13/EB/NIBIB NIH HHS; R01 EB000557-09/EB/NIBIB NIH HHS; R01 EB002807-30/EB/NIBIB NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Indicators and Reagents; 0/Nitrogen Isotopes; 0/Nitrogen Oxides; 0/Nitrogen Radioisotopes; 0/Solutions; 0/Spin Labels; 7732-18-5/Water; 7782-39-0/Deuterium |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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