SABRE Hyperpolarization of Exchangeable Protons in Methanol- through Dynamic Covalent Bonds.

Utilizing -hydrogen (-H)-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- by introducing dynamic covalent bonds as reversible exchange following the SABRE process. To release the hyperpolarized CDOH, the pyridine-based ligands with aldehyde groups underwent acetal exchange between the aldehyde and hydroxyl groups of CDOH 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-. Our work broadens SABRE's chemical system compatibility and possible applications.