Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Novel Biradicals for Direct Excitation Highfield Dynamic Nuclear Polarization. / Bothe, Sarah; Nowag, Jens; Klimavičius, Vytautas и др.
в: Journal of Physical Chemistry C, Том 122, № 21, 31.05.2018, стр. 11422-11432.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Novel Biradicals for Direct Excitation Highfield Dynamic Nuclear Polarization
AU - Bothe, Sarah
AU - Nowag, Jens
AU - Klimavičius, Vytautas
AU - Hoffmann, Markus
AU - Troitskaya, Tatiana I.
AU - Amosov, Evgenii V.
AU - Tormyshev, Victor M.
AU - Kirilyuk, Igor
AU - Taratayko, Andrey
AU - Kuzhelev, Andrey
AU - Parkhomenko, Dmitriy
AU - Bagryanskaya, Elena
AU - Gutmann, Torsten
AU - Buntkowsky, Gerd
PY - 2018/5/31
Y1 - 2018/5/31
N2 - Synthesis of novel trityl-nitroxyl biradicals and their performance as polarization agents in DNP-enhanced solid-state MAS NMR spectroscopy is presented. Signal enhancements in 1H, 1H → 13C CP MAS, and 13C MAS experiments obtained with these radicals dissolved in 1,1,2,2-tetrachloroethane (TCE) solution are compared with the enhancements obtained from TCE solutions of binitroxyl radicals. The signal enhancements are correlated with the distance between the radical centers of the biradicals, as determined by theoretical structure calculations. Some of the biradical TCE solutions display direct-channel resonances in 13C MAS experiments as well as indirect channel resonances induced via the proton spin reservoir. Differential scanning calorimetry reveals that only these solutions do not form any solid crystalline phases upon rapid cooling, suggesting that molecular motions needed for polarization transfer from radicals to 13C via the proton spin reservoir remain active at the experimental low temperatures of nominal 120 K. DNP magnetic field sweep enhancement profiles for selected new biradicals are presented as well. These indicate that the DNP transfer is dominated by the cross-effect mechanism.
AB - Synthesis of novel trityl-nitroxyl biradicals and their performance as polarization agents in DNP-enhanced solid-state MAS NMR spectroscopy is presented. Signal enhancements in 1H, 1H → 13C CP MAS, and 13C MAS experiments obtained with these radicals dissolved in 1,1,2,2-tetrachloroethane (TCE) solution are compared with the enhancements obtained from TCE solutions of binitroxyl radicals. The signal enhancements are correlated with the distance between the radical centers of the biradicals, as determined by theoretical structure calculations. Some of the biradical TCE solutions display direct-channel resonances in 13C MAS experiments as well as indirect channel resonances induced via the proton spin reservoir. Differential scanning calorimetry reveals that only these solutions do not form any solid crystalline phases upon rapid cooling, suggesting that molecular motions needed for polarization transfer from radicals to 13C via the proton spin reservoir remain active at the experimental low temperatures of nominal 120 K. DNP magnetic field sweep enhancement profiles for selected new biradicals are presented as well. These indicate that the DNP transfer is dominated by the cross-effect mechanism.
KW - TRITYL-NITROXIDE BIRADICALS
KW - INTRACELLULAR OXYGEN PROBES
KW - ENHANCED NMR-SPECTROSCOPY
KW - SOLID-STATE
KW - POLARIZING AGENTS
KW - ABSOLUTE SENSITIVITY
KW - HIGH-FREQUENCY
KW - AQUEOUS-MEDIA
KW - RADICALS
KW - EFFICIENT
UR - http://www.scopus.com/inward/record.url?scp=85046662792&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.8b02570
DO - 10.1021/acs.jpcc.8b02570
M3 - Article
AN - SCOPUS:85046662792
VL - 122
SP - 11422
EP - 11432
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 21
ER -
ID: 13754619