Highly efficient polarizing agents for MAS-DNP of proton-dense molecular solids

Efficiently hyperpolarizing proton-dense molecular solids through dynamic nuclear polarization solid-state NMR is still an unmet challenge. Polarizing agents (PAs) developed so far do not perform well on proton-rich systems, such as organic microcrystals and biomolecular assemblies. In this paper, we introduce a new PA, cAsymPol-POK, and report outstanding hyperpolarization efficiency on a protein and pharmaceutical drugs at high magnetic fields and fast magic angle spinning frequencies.