Intermolecular Interactions and Structural Motifs in Crystalline Solids

Solid‐state NMR is a well‐established technique for characterizing packing motifs in the solid state. The through‐space dipolar couplings among nuclei can be used to probe intermolecular interactions via either cross polarization (CP) or recoupling experiments. Besides, packing of molecules in the solid state can have significant influences on the local environment, and thereby the chemical shifts of protons. Examples are given that illustrate the dramatic ring‐current effects, host‐guest interactions, and formations of nanostructures, and distinctions among polymorphs. In several cases, experimental results are paired with ab initio calculations of solid‐state structures to provide a full interpretation of the data.