Zhan, Xiao, Zhanhong Guo, Huijun Sun, Anran Dai, Min Zhang, Xiaohong Cui, Xinchang Wang, Zhongqun Tian, and Zhong Chen. “SABRE Hyperpolarization of Exchangeable Protons in Methanol-D4 through Dynamic Covalent Bonds.” Analytical Chemistry 95, no. 31 (August 8, 2023): 11613–20.
https://doi.org/10.1021/acs.analchem.3c01049.
Utilizing para-hydrogen (p-H2)-induced hyperpolarization to increase the sensitivity of nuclear magnetic resonance, especially signal amplification by reversible exchange (SABRE), has been widely studied. Here, we achieved hyperpolarization of exchangeable protons in methanol-d4 by introducing dynamic covalent bonds as reversible exchange following the SABRE process. To release the hyperpolarized CD3OH, the pyridine-based ligands with aldehyde groups underwent acetal exchange between the aldehyde and hydroxyl groups of CD3OH after being first hyperpolarized by SABRE. Our mechanistic study highlights the importance of the reversible exchange of functional groups and chemical kinetics in realizing hyperpolarization of exchangeable protons in methanol-d4. Our work broadens SABRE’s chemical system compatibility and possible applications.