Dissolution dynamic nuclear polarization of deuterated molecules enhanced by cross-polarization

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Dissolution dynamic nuclear polarization of deuterated molecules enhanced by cross-polarization, J. Chem. Phys., 2016, 145, 194203

 

Recent years have witnessed the rapid development of both theoretical and experimental aspects of dissolution dynamic nuclear polarization (D-DNP). This method allows one to achieve dramatic signal enhancements in liquid-state nuclear magnetic resonance (NMR) experiments. D-DNP offers a wealth of novel possibilities for clinical applications like magnetic resonance imaging (MRI), drug screening, and NMR of biomolecules. To extend the lifetimes of hyperpolarization, D-DNP has been combined with long-lived states. Apart from a few exotic nuclei, D-DNP has so far mostly focused on 1H and 13C. Here we propose to extend this methodology by adding deuterium to the list of accessible nuclei, opening new avenues for D-DNP, such as the study of the dynamics of deuterated molecules and improved sensitivity of deuterium NMR.

 

 

In conclusion, we have shown how one can “indirectly” hyperpolarize deuterium nuclei coupled to a 13C nucleus via CP from 1H to 13C using weak rf amplitudes. Furthermore, it has been shown that some constituents of the density operator of a CD2  system can have lifetimes that, although shorter than T1(Cz ) = 23 s for the case at hand, are much longer than T1(Dz) = 0.7 s of the Zeeman polarization of individual deuterium nuclei in the same system. These observations expand the scope ofDNPby adding another nucleus to the list of possible observables. Thus, deuterium-based NMR with improved sensitivity on longer time scales becomes possible.

 

N'hésitez pas à consulter le communiqué de presse associé à cet article : Polarisation nucléaire dynamique de molécules enrichies en deutérium 

 

 

Résumé: 

J. Chem. Phys., 2016, 145, 194203

 

We present novel means to hyperpolarize deuterium nuclei in 13CD2  groups at cryogenic temperatures. The method is based on cross-polarization from 1 H to 13 C and does not require any radio-frequency fields applied to the deuterium nuclei. After rapid dissolution, a new class of longlived spin states can be detected indirectly by 13C NMR in solution. These long-lived states result from a sextet-triplet imbalance (STI) that involves the two equivalent deuterons with spin I  = 1. An STI has similar properties as a triplet-singlet imbalance that can occur in systems with two equivalent I  = 1/2  spins. Although the lifetimes TSTI  are shorter than T1(Cz), they can exceed the life-time T1(Dz) of deuterium Zeeman magnetization by a factor of more than 20.

 

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Dissolution dynamic nuclear polarization of deuterated molecules enhanced by cross-polarization

 

Dennis Kurzbach, Emmanuelle M. M.Weber, Aditya Jhajharia, Samuel F. Cousin, Aude Sadet, Sina Marhabaie, Estel Canet, Nicolas Birlirakis, Jonas Milani, Sami Jannin, Dmitry Eshchenko, Alia Hassan, Roberto Melzi, Stephan Luetolf, Marco Sacher, Marc Rossire, James Kempf, Joost A. B. Lohman, Matthias Weller, Geoffrey Bodenhausen, and Daniel Abergel

 

J. Chem. Phys., 2016, 145, 194203

 

DOI : 10.1063/1.4967402