Chapter 15. Singlet-assisted Diffusion NMR

The incorporation of long-lived singlet states into diffusion-NMR experiments allows the translational motion of molecules to be observed over many minutes. This is a significant improvement of the observation times available in traditional NMR techniques, and allows for measurements of large macromolecules with slow diffusion coefficients and restricted diffusion in macroporous systems. This chapter introduces the methodology for singlet-assisted diffusion-NMR (SAD-NMR), a method that uses nearly-equivalent spin-1/2 pairs to store spatially encoded magnetization in long-lived singlet states for up to ten minutes. The potential for this method to characterize the morphological properties of macroporous media is demonstrated, and future real-world applications are discussed.