Intermolecular interactions are important tools to control the formation of supramolecular complexes and networks.  Hydrogen bonding and pi-pi interactions have been used for many years in this way, yet the 'new kid on the block' is halogen bonding, the interaction of a halogen bond and electron donors.

In his CrystEngComm Highlight article, Professor Kari Rissanen, University of Jyväskylä, Finland, explores the recent increase in the use of this interactions.  Citing the work in particular of Resnati and Metrangolo, he illustrates the steady increase in the nunmber of publications that focus on this new tool for crystal engineers, and shows the usefulness of halogen bonding, which in some circumstances, can be more dominant than the other intermolecular interactions.

The increasing use of halogen bonding in crystal engineering opens up new insights and possibilities for researchers in this area, and also other disciplines, ' The significance of halogen bonding in biological systems has very recently attracted attention,' says Rissanen.