  Dynamic nuclear polarization (DNP) is an NMR sensitivity enhancement
technique that mediates polarization transfer from unpaired electrons to
NMR-active nuclei. Despite its success in elucidating important structural
information on biological and inorganic materials, the detailed
polarization-transfer pathway-from the electrons to the nearby and then the
bulk solvent nuclei, and finally to the molecules of interest-remains unclear.
In particular, the nuclei in the paramagnetic polarizing agent play significant
roles in relaying the enhanced NMR polarizations to more remote nuclei. Despite
their importance, the direct NMR observation of these nuclei is challenging
because of poor sensitivity. Here, we show that a combined DNP and electron
decoupling approach can facilitate direct NMR detection of these nuclei. We
achieved an ~80 % improvement in NMR intensity via electron decoupling at 0.35
T and 80 K on trityl radicals. Moreover, we recorded a DNP enhancement factor
of $\epsilon$ ~ 90 and ~11 % higher NMR intensity using electron decoupling on
a paramagnetic metal-organic framework, magnesium hexaoxytriphenylene (MgHOTP
MOF).
