Design and applications of halogen-bonded responsive materials

From the prehistory, humans have been creating materials with the goal of helping their daily chores. Therefore, knowing the problem, one can design apparatus to overcome common drawbacks and it is particularly attractive to layout materials from smaller things. Applying this concept to chemistry, the design of materials from small molecules and the interaction between them, give us the definition of the “Supramolecular Chemistry”. Recently, Supramolecular Chemistry has been deeply studied for many groups on every side of the world, in which molecules respond to stimuli applied from diverse non-internal sources by undergoing reversible transformations between two different states. The importance of these phenomena rises from the molecules undergoing changes in their noted characteristics (e.g. electronic and topological) and then acting as switching different elements in functional materials. Thus, designing a functional system responding to external stimuli, one can create a material which provides us with predictable response. In the recent years, several studies related to halogen bonding have been developed by numerous groups. The remarkable interest in this non-covalent interaction may find explanation in its properties (specificity, robustness and high directionality), which present more advantages than others non-covalent interactions frequently used in Supramolecular Chemistry. Therefore, highly motivated from the discussion above mentioned, I considered three well known topics in supramolecular chemistry to review the studies developed until now, adding halogen bonding properties in order to improve their characteristics. These topics are responsive Liquid Crystals (LC), Metal Organic Frameworks (MOFs) and block co-polymers.