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. 2016 Jan 1;7(1):550-558.
doi: 10.1039/c5sc02921j. Epub 2015 Oct 13.

Rational design of dinitroxide biradicals for efficient cross-effect dynamic nuclear polarization

Dominik J Kubicki  1 , Gilles Casano  2 , Martin Schwarzwälder  3 , Sébastien Abel  2 , Claire Sauvée  2 , Karthikeyan Ganesan  2 , Maxim Yulikov  3 , Aaron J Rossini  1 , Gunnar Jeschke  3 , Christophe Copéret  3 , Anne Lesage  4 , Paul Tordo  2 , Olivier Ouari  2 , Lyndon Emsley  1
Affiliations

Rational design of dinitroxide biradicals for efficient cross-effect dynamic nuclear polarization

Dominik J Kubicki et al. Chem Sci. .

Abstract

A series of 37 dinitroxide biradicals have been prepared and their performance studied as polarizing agents in cross-effect DNP NMR experiments at 9.4 T and 100 K in 1,1,2,2-tetrachloroethane (TCE). We observe that in this regime the DNP performance is strongly correlated with the substituents on the polarizing agents, and electron and nuclear spin relaxation times, with longer relaxation times leading to better enhancements. We also observe that deuteration of the radicals generally leads to better DNP enhancement but with longer build-up time. One of the new radicals introduced here provides the best performance obtained so far under these conditions.

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Figures

Fig. 1
Fig. 1. Structures and names of the radicals investigated in this study: (a) the bTurea series, (b) the bCTurea series, (c and e) the PyPol series, (d) the bTbK series. The TOTAPOL (f) and bCTbK (d) structures given for completeness. The prefix spiro indicates junction through just one carbon atom. PEG indicates a –CH2CH2O– unit. Molecular weights and synthetic routes are given in the ESI.
Fig. 2
Fig. 2. 1H–13C CP DNP enhancement (εC CP) for bulk solutions of TCE with 16 mM radical.
Fig. 3
Fig. 3. DNP enhancement (εC CP) as a function of saturation factor (T1e·T2e) and relaxation factor (T1e·T2e·T1n) for selected compounds from (a and b) the bTurea series (TCE, 16 mM), (c and d) the PyPol series (TCE, 16 mM), (e and f) the bTbK series (TCE, 16 mM). The data points marked with an asterisk are taken from the previous study by Zagdoun et al. Error bars are shown where larger than the symbols.
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References

    1. Carver T. R., Slichter C. P. Phys. Rev. 1953;92:212–213.
    1. Goldman M., Spin Temperature and Nuclear Magnetic Resonance in Solids (Monographs on Physics), Oxford University Press, 1970.
    1. Abragam A. and Goldman M., Nuclear Magnetism: Order and Disorder (Monographs on Physics), Oxford University Press, 1982.
    1. Becerra L. R., Gerfen G. J., Temkin R. J., Singel D. J., Griffin R. G. Phys. Rev. Lett. 1993;71:3561–3564. - PubMed
    1. Hall D. A., Maus D. C., Gerfen G. J., Inati S. J., Becerra L. R., Dahlquist F. W., Griffin R. G. Science. 1997;276:930–932. - PubMed