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Direct dynamic nuclear polarization of 15 N and 13 C spins at 14.1 T using a trityl radical and magic angle spinning.
- Source :
-
Solid state nuclear magnetic resonance [Solid State Nucl Magn Reson] 2019 Aug; Vol. 100, pp. 85-91. Date of Electronic Publication: 2019 Apr 02. - Publication Year :
- 2019
-
Abstract
- We investigate solid-state dynamic nuclear polarization of <superscript>13</superscript> C and <superscript>15</superscript> N nuclei using monoradical trityl OX063 as a polarizing agent in a magnetic field of 14.1 T with magic angle spinning at ∼100 K. We monitored the field dependence of direct <superscript>13</superscript> C and <superscript>15</superscript> N polarization for frozen [ <superscript>13</superscript> C, <superscript>15</superscript> N] urea and achieved maximum absolute enhancement factors of 240 and 470, respectively. The field profiles are consistent with polarization of <superscript>15</superscript> N spins via either the solid effect or the cross effect, and polarization of <superscript>13</superscript> C spins via a combination of cross effect and solid effect. For microcrystalline, <superscript>15</superscript> N-enriched tryptophan synthase sample containing trityl radical, a 1500-fold increase in <superscript>15</superscript> N signal was observed under microwave irradiation. These results show the promise of trityl radicals and their derivatives for direct polarization of low gamma, spin-½ nuclei at high magnetic fields and suggest a novel approach for selectively polarizing specific moieties or for polarizing systems which have low levels of protonation.<br /> (Copyright © 2019 Elsevier Inc. All rights reserved.)
Details
- Language :
- English
- ISSN :
- 1527-3326
- Volume :
- 100
- Database :
- MEDLINE
- Journal :
- Solid state nuclear magnetic resonance
- Publication Type :
- Report
- Accession number :
- 31026722
- Full Text :
- https://doi.org/10.1016/j.ssnmr.2019.03.009