Supramolecular inorganic frameworks: "dynamic" challenges for structural chemistry

The supramolecular chemistry of discrete assemblies of various topologies (cages, grids, helices, etc.) has been extensively studied. With regards to the supramolecular chemistry of infinite solids, attention is usually focussed on the design of an efficient, programmed assembly motif through the choice of suitable building blocks. However, as well illustrated by the discrete structures, a hallmark property of a supramolecular system is its ability to reversibly assemble to optimize its structure, effectively error checking. For a rigid infinite framework, this feature is less obvious. Error checking is manifested in an extended framework through structural rearrangements in the solid state. Coordination frameworks, as they are often at least partially sustained by weaker interactions, can demonstrate such dynamic behavior in response to some external stimulus. Selected examples, chosen to illustrate a range of network types and rearrangements, will be discussed in this short review.