Optical Hyperpolarization of 1H and 19F Spins in Organic Liquids.

Optical dynamic nuclear polarization (oDNP) in liquids offers a microwave-free route to NMR signal enhancement but has so far relied on a limited number of dye-radical systems with restricted photostability, typically requiring high-power laser sources and sample flow to mitigate photobleaching of the dye. Here, we investigate porphyrin-BDPA pairs for oDNP in organic solvents using illumination from an incoherent light-emitting diode, providing 1H enhancement factors up to -7.5 at 0.35 T and -25 at 0.16 T in bulk solutions. Beyond 1H hyperpolarization, we show optical enhancement of 19F nuclei in bulk solutions (+5 at 0.37 T), with the positive enhancement indicating a significant scalar contribution to the electron-nuclear interaction. The improved photostability of porphyrins enables one- and two-dimensional oDNP experiments without sample flow, thereby simplifying the experimental implementation of oDNP at low magnetic fields.