Figure 1.

The LIGHT-SABRE (Low Irradiation Generation of High Tesla Signal Amplification by Reversible Exchange) process enables hyperpolarization at any magnetic field. Parahydrogen and ¹⁵N-pyridine dissolved in the solvent are in constant chemical exchange with their respective bound forms on the Iridium complex, which can be viewed as an AA’XX’ spin system (with A=¹H and X=¹⁵N). Singlet hyperpolarization is converted to magnetization on the bound ¹⁵N-pyridine by the LIGHT-SABRE pulses and finally accumulated on the free pyridine through the exchange processes. The catalytic system used was [IrCl(COD)(IMes)] (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene; COD = cyclooctadiene) as precursor; upon hydrogenation COD and Cl⁻ are replaced by the hydrogen and pyridine to form the catalytically active form [IrH₂Py₃(IMes)]⁺.[4, 5]