Crystal engineering enables room-temperature triplet-DNP in cocrystals

Abstract

We demonstrate the crystal engineering of cocrystalline polarization matrices for triplet-dynamic nuclear polarization at room temperature. Cocrystals were designed using nicotinamide as a hydrogen bonding coformer to enable the triplet-DNP of aliphatic dicarboxylic acids. The rigid molecular frameworks formed through controlled hydrogen-bonding and π–π interactions maintain sufficiently long T₁ values for spin diffusion, leading to room-temperature triplet-DNP. This crystal engineering expands the range of molecules that can be polarized using triplet-DNP. These findings establish crystal engineering as a promising strategy for developing polarization materials and advancing the applications of room-temperature hyperpolarization in NMR and MRI.