Crystal engineering of coordination networks: from building blocks and linkers to frameworks

Crystal engineering is the field of chemistry that studies the design, properties, and applications of crystals. The “design” element of crystal engineering was the initial focus of crystal engineering research and developed in the 1990s after key publications. Today, crystal engineers are focused upon advanced functional materials, ranging from pharmaceutical materials, that provide enhanced physicochemical and biological properties, to porous materials, which offer benchmark selectivity to enable removal of trace impurities from complex mixtures of gases and liquids. Crystals, with their ordered structures, are well suited to provide insight into structure-function relationships that in turn enables “design” of new crystal structures with improved properties. Intermolecular interactions such as hydrogen and halogen bonding can be exploited in this context, but it is the directionality and strength of coordination bonding that has enabled rapid growth in the study of coordination networks (CNs). CNs, which are comprised of metal ions linked by organic or inorganic ligands are exceptionally diverse in composition, structure, and properties, with each component offering differing possibilities for further modification. This thesis aims to explore how ligand design can influence the structure and properties of CNs. In particular, CN structures formed from the following components or “building blocks” are investigated: bifunctional N-donor carboxylate ligands with metal dications; lithium and L-proline; and a copper sulfate-based metal cluster. The properties of these CNs were investigated with a focus on guest-induced structural flexibility and polymorphism, followed by an examination of relevant applications of the materials.