Photochemically induced dynamic nuclear polarization: Basic principles and applications

Photo-CIDNP, also known as photochemically induced dynamic nuclear polarization, is a particularly effective method to hyperpolarize nuclear spins under minimally perturbative conditions. In this article, we will focus on the basic principles and applications of this technique in the context of liquid-state NMR spectroscopy. The theory of photo-CIDNP in the high-field limit in liquids will be discussed frst, followed by the presentation of a selected number of recent applications, including nuclear spin hyperpolarization and the mechanistic analysis of chemical processes involving photoinduced electron transfer and protein folding. Major advantages of photo-CIDNP include its applicability across a wide range of magnetic fields and temperatures and its short (<1 s) hyperpolarization times.