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Limits in Proton Nuclear Singlet-State Lifetimes Measured with para-Hydrogen-Induced Polarization
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SYSNO ASEP 0467021 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Limits in Proton Nuclear Singlet-State Lifetimes Measured with para-Hydrogen-Induced Polarization Tvůrce(i) Zhang, Y. (US)
Duan, X. (US)
Soon, P. C. (US)
Sychrovský, Vladimír (UOCHB-X) RID, ORCID
Canary, J. W. (US)
Jerschow, A. (US)Zdroj.dok. ChemPhysChem. - : Wiley - ISSN 1439-4235
Roč. 17, č. 19 (2016), s. 2967-2971Poč.str. 5 s. Jazyk dok. eng - angličtina Země vyd. DE - Německo Klíč. slova chemical shift anisotropy ; dimethyl fumarate ; hyperpolarization ; paramagnetic relaxation ; singlet lifetime limits Vědní obor RIV CF - Fyzikální chemie a teoretická chemie Institucionální podpora UOCHB-X - RVO:61388963 UT WOS 000386790100003 EID SCOPUS 84989812375 DOI https://doi.org/10.1002/cphc.201600663 Anotace The synthesis of a hyperpolarized molecule was developed, where the polarization and the singlet state were preserved over two controlled chemical steps. Nuclear singlet-state lifetimes close to 6 min for protons are reported in dimethyl fumarate. Owing to the high symmetry (AA'X3X3' and A(2) systems), the singlet-state readout requires either a chemical de-symmetrization or a long and repeated spin lock. Using DFT calculations and relaxation models, we further determine nuclear spin singlet lifetime limiting factors, which include the intramolecular dipolar coupling mechanism (proton-proton and proton-deuterium), the chemical shift anisotropy mechanism (symmetric and antisymmetric), and the intermolecular dipolar coupling mechanism (to oxygen and deuterium). If the limit of paramagnetic relaxation caused by residual oxygen could be lifted, the intramolecular dipolar coupling to deuterium would become the limiting relaxation mechanism and proton lifetimes upwards of 26 min could become available in the molecules considered here (dimethyl maleate and dimethyl fumarate). Pracoviště Ústav organické chemie a biochemie Kontakt asep@uochb.cas.cz ; Kateřina Šperková, Tel.: 232 002 584 ; Jana Procházková, Tel.: 220 183 418 Rok sběru 2017
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