Inukai, Munehiro, Haruki Sato, Koichiro Miyanishi, Makoto Negoro, Akinori Kagawa, Yuta Hori, Yasuteru Shigeta, Takuya Kurihara, and Koichi Nakamura. “Cocrystalline Matrices for Hyperpolarization at Room Temperature Using Photoexcited Electrons.” Journal of the American Chemical Society 146, no. 21 (May 29, 2024): 14539–45.
https://doi.org/10.1021/jacs.4c01050.
We propose using cocrystals as effective polarization matrices for triplet dynamic nuclear polarization (DNP) at room temperature. The polarization source can be uniformly doped into cocrystals formed through acid–acid, amide–amide, and acid–amide synthons. The dense-packing crystal structures, facilitated by multiple hydrogen bonding and π–π interactions, result in extended T1 relaxation times, enabling efficient polarization diffusion within the crystals. Our study demonstrates the successful polarization of a DNP-magnetic resonance imaging molecular probe, such as urea, within a cocrystal matrix at room temperature using triplet-DNP.