Parahydrogen-induced hyperpolarization of a Zn(<scp>ii</scp>) complex using NMR signal amplification by reversible exchange (SABRE)

Although Zn(II) complexes are critical metallobiomolecules in many biological environments, no parahydrogen-based hyperpolarization technique has been reported for such species. Herein, Zn(II)-tris(2-pyridylmethyl)amine (TPA) was hyperpolarized using NMR signal amplification by reversible exchange (SABRE) as a rapid, low-cost, portable, and repeatable technique for spin hyperpolarization. The hyperpolarization of TPA was not significantly affected by Zn(II) relaxation, whereas the polarization trends with respect to magnetic fields and Zn(II) concentrations differed from those of previous reports. The use of SABRE on metal complexes enables new NMR-based analytical and MRI applications. Thus, SABRE is a promising technique for a wide range of polarizable biomaterials.