Limits in Proton Nuclear Singlet-State Lifetimes Measured with para-Hydrogen-Induced Polarization

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F16%3A00467021" target="_blank" >RIV/61388963:_____/16:00467021 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68407700:21230/16:00303298

Výsledek na webu

<a href="http://dx.doi.org/10.1002/cphc.201600663" target="_blank" >http://dx.doi.org/10.1002/cphc.201600663</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1002/cphc.201600663" target="_blank" >10.1002/cphc.201600663</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Limits in Proton Nuclear Singlet-State Lifetimes Measured with para-Hydrogen-Induced Polarization

Popis výsledku v původním jazyce

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).

Název v anglickém jazyce

Limits in Proton Nuclear Singlet-State Lifetimes Measured with para-Hydrogen-Induced Polarization

Popis výsledku anglicky

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).

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

CF - Fyzikální chemie a teoretická chemie

OECD FORD obor

—

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

ChemPhysChem

ISSN

1439-4235

e-ISSN

—

Svazek periodika

17

Číslo periodika v rámci svazku

19

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

5

Strana od-do

2967-2971

Kód UT WoS článku

000386790100003

EID výsledku v databázi Scopus

2-s2.0-84989812375