Mixed-valence compounds as polarizing agents for Overhauser dynamic nuclear polarization in solids.

In this paper we investigate a novel set of polarizing agents - mixed-valence compounds - by theoretical and experimental methods and demonstrate their performance in high-field Dynamic Nuclear Polarization (DNP) NMR experiments in the solid state. Mixed-valence compounds constitute a group of molecules, in which molecular mobility persists even in solids. Consequently, such polarizing agents can be used to perform Overhauser-DNP experiments in solid-state, with favorable conditions for dynamic nuclear polarization formation at ultra-high magnetic fields.