Electron Decoupling with Chirped Microwave Pulses for Rapid Signal Acquisition and Electron Saturation Recovery.

Autor: Alaniva N; Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA., Saliba EP; Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA., Sesti EL; Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA., Judge PT; Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA.; Department of Biochemistry, Biophysics, and Biology, Washington University in St. Louis, School of Medicine, 660 S. Euclid Ave, St Louis, MO, 63110, USA., Barnes AB; Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO, 63130, USA.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2019 May 27; Vol. 58 (22), pp. 7259-7262. Date of Electronic Publication: 2019 Apr 25.
DOI: 10.1002/anie.201900139
Abstrakt: Dynamic nuclear polarization (DNP) increases NMR sensitivity by transferring polarization from electron to nuclear spins. Herein, we demonstrate that electron decoupling with chirped microwave pulses enables improved observation of DNP-enhanced 13 C spins in direct dipolar contact with electron spins, thereby leading to an optimal delay between transients largely governed by relatively fast electron relaxation. We report the first measurement of electron longitudinal relaxation time (T 1e ) during magic angle spinning (MAS) NMR by observation of DNP-enhanced NMR signals (T 1e =40±6 ms, 40 mM trityl, 4.0 kHz MAS, 4.3 K). With a 5 ms DNP period, electron decoupling results in a 195 % increase in signal intensity. MAS at 4.3 K, DNP, electron decoupling, and short recycle delays improve the sensitivity of 13 C in the vicinity of the polarizing agent. This is the first demonstration of recovery times between MAS-NMR transients being governed by short electron T 1 and fast DNP transfer.
(© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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