Dynamic nuclear polarization in inorganic solids from paramagnetic metal ion dopants

In this chapter, an introduction to dynamic nuclear polarization (DNP) solid state nuclear magnetic resonance (NMR) is given. The main focus lies in presenting the use of paramagnetic metal ion dopants in inorganic materials as endogenous sources of hyperpolarization. Relevant concepts of NMR in the presence of paramagnetic centers are introduced and the main DNP mechanisms are explained with a quantum mechanical formalism. The presented theoretical basis allows an in-depth discussion of the limits and possibilities of metal ion-based DNP (MIDNP). Conceptual and practical differences of this approach and exogenous DNP are discussed, in particular the advantages offered by MIDNP as a tool for structural elucidation of inorganic solids are highlighted. Finally, practical considerations to help implementing this experimental technique are given.