Time domain DNP with the NOVEL sequence
We present results of a pulsed dynamic nuclear polarization (DNP) study at 0.35 T (9.7 GHz/14.7 MHz for electron/1H Larmor frequency) using a lab frame-rotating frame cross polarization experiment that employs electron spin locking fields that match the 1H nuclear Larmor frequency, the so called NOV...
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| Format: | Article |
| Language: | en_US |
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IOP Publishing
2017
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| Online Access: | http://hdl.handle.net/1721.1/110278 https://orcid.org/0000-0001-9092-612X https://orcid.org/0000-0003-1589-832X |
| _version_ | 1826194754127265792 |
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| author | Can, Thach V Walish, Joseph John Swager, Timothy M Griffin, Robert Guy |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Can, Thach V Walish, Joseph John Swager, Timothy M Griffin, Robert Guy |
| author_sort | Can, Thach V |
| collection | MIT |
| description | We present results of a pulsed dynamic nuclear polarization (DNP) study at 0.35 T (9.7 GHz/14.7 MHz for electron/1H Larmor frequency) using a lab frame-rotating frame cross polarization experiment that employs electron spin locking fields that match the 1H nuclear Larmor frequency, the so called NOVEL (nuclear orientation via electron spin locking) condition. We apply the method to a series of DNP samples including a single crystal of diphenyl nitroxide (DPNO) doped benzophenone (BzP), 1,3-bisdiphenylene-2-phenylallyl (BDPA) doped polystyrene (PS), and sulfonated-BDPA (SA-BDPA) doped glycerol/water glassy matrices. The optimal Hartman-Hahn matching condition is achieved when the nutation frequency of the electron matches the Larmor frequency of the proton, ω[subscript 1S] = ω[subscript 0I], together with possible higher order matching conditions at lower efficiencies. The magnetization transfer from electron to protons occurs on the time scale of ∼100 ns, consistent with the electron-proton couplings on the order of 1-10 MHz in these samples. In a fully protonated single crystal DPNO/BzP, at 270 K, we obtained a maximum signal enhancement of ε = 165 and the corresponding gain in sensitivity of ε(T[subscript 1]/T[subscript B])[superscript 1/2] = 230 due to the reduction in the buildup time under DNP. In a sample of partially deuterated PS doped with BDPA, we obtained an enhancement of 323 which is a factor of ∼3.2 higher compared to the protonated version of the same sample and accounts for 49% of the theoretical limit. For the SA-BDPA doped glycerol/water glassy matrix at 80 K, the sample condition used in most applications of DNP in nuclear magnetic resonance, we also observed a significant enhancement. Our findings demonstrate that pulsed DNP via the NOVEL sequence is highly efficient and can potentially surpass continuous wave DNP mechanisms such as the solid effect and cross effect which scale unfavorably with increasing magnetic field. Furthermore, pulsed DNP is also a promising avenue for DNP at high temperature. |
| first_indexed | 2024-09-23T10:01:17Z |
| format | Article |
| id | mit-1721.1/110278 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:01:17Z |
| publishDate | 2017 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/1102782020-12-12T02:23:32Z Time domain DNP with the NOVEL sequence Can, Thach V Walish, Joseph John Swager, Timothy M Griffin, Robert Guy Massachusetts Institute of Technology. Department of Chemistry Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology) Can, Thach V Walish, Joseph John Swager, Timothy M Griffin, Robert Guy We present results of a pulsed dynamic nuclear polarization (DNP) study at 0.35 T (9.7 GHz/14.7 MHz for electron/1H Larmor frequency) using a lab frame-rotating frame cross polarization experiment that employs electron spin locking fields that match the 1H nuclear Larmor frequency, the so called NOVEL (nuclear orientation via electron spin locking) condition. We apply the method to a series of DNP samples including a single crystal of diphenyl nitroxide (DPNO) doped benzophenone (BzP), 1,3-bisdiphenylene-2-phenylallyl (BDPA) doped polystyrene (PS), and sulfonated-BDPA (SA-BDPA) doped glycerol/water glassy matrices. The optimal Hartman-Hahn matching condition is achieved when the nutation frequency of the electron matches the Larmor frequency of the proton, ω[subscript 1S] = ω[subscript 0I], together with possible higher order matching conditions at lower efficiencies. The magnetization transfer from electron to protons occurs on the time scale of ∼100 ns, consistent with the electron-proton couplings on the order of 1-10 MHz in these samples. In a fully protonated single crystal DPNO/BzP, at 270 K, we obtained a maximum signal enhancement of ε = 165 and the corresponding gain in sensitivity of ε(T[subscript 1]/T[subscript B])[superscript 1/2] = 230 due to the reduction in the buildup time under DNP. In a sample of partially deuterated PS doped with BDPA, we obtained an enhancement of 323 which is a factor of ∼3.2 higher compared to the protonated version of the same sample and accounts for 49% of the theoretical limit. For the SA-BDPA doped glycerol/water glassy matrix at 80 K, the sample condition used in most applications of DNP in nuclear magnetic resonance, we also observed a significant enhancement. Our findings demonstrate that pulsed DNP via the NOVEL sequence is highly efficient and can potentially surpass continuous wave DNP mechanisms such as the solid effect and cross effect which scale unfavorably with increasing magnetic field. Furthermore, pulsed DNP is also a promising avenue for DNP at high temperature. National Institute for Biomedical Imaging and Bioengineering (U.S.) (Grant No. EB-002804) National Institute for Biomedical Imaging and Bioengineering (U.S.) (Grant No. EB-002026) National Institute of General Medical Sciences (U.S.) (Grant No. GM095843) 2017-06-26T20:14:24Z 2017-06-26T20:14:24Z 2015-08 2015-04 Article http://purl.org/eprint/type/JournalArticle 0021-9606 1089-7690 http://hdl.handle.net/1721.1/110278 Can, T. V., J. J. Walish, T. M. Swager, and R. G. Griffin. “Time Domain DNP with the NOVEL Sequence.” J. Chem. Phys. 143, no. 5 (August 7, 2015): 054201. © 2015 AIP Publishing LLC. https://orcid.org/0000-0001-9092-612X https://orcid.org/0000-0003-1589-832X en_US http://dx.doi.org/10.1063/1.4927087 Journal of Chemical Physics Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf IOP Publishing PMC |
| spellingShingle | Can, Thach V Walish, Joseph John Swager, Timothy M Griffin, Robert Guy Time domain DNP with the NOVEL sequence |
| title | Time domain DNP with the NOVEL sequence |
| title_full | Time domain DNP with the NOVEL sequence |
| title_fullStr | Time domain DNP with the NOVEL sequence |
| title_full_unstemmed | Time domain DNP with the NOVEL sequence |
| title_short | Time domain DNP with the NOVEL sequence |
| title_sort | time domain dnp with the novel sequence |
| url | http://hdl.handle.net/1721.1/110278 https://orcid.org/0000-0001-9092-612X https://orcid.org/0000-0003-1589-832X |
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