Halogen•••Halogen Interactions: Nature, Directionality and Applications

Halogen center dot center dot center dot Shalogen interaction is a highly debated and important topic in crystal engineering and supramolecular chemistry. There are controversies about the nature and geometry of these interactions. F, Cl, Br and I are the four halogens involved in these interactions. Very often the lighter and the heavier halogens behave differently. The nature of the interactions also depends upon the nature of the atom which is covalently bonded to the halogens. In this review different homo-halogen center dot center dot center dot halogen, hetero-halogen center dot center dot center dot halogen, halogen center dot center dot center dot halide interactions, their natures, and preferred geometries have been discussed. Different motifs of halogen center dot center dot center dot halogen interactions, interchangeability of the halogen center dot center dot center dot halogen interactions with other supramolecular synthons and interchangeability between different halogens and other functional groups also have been discussed. Some of the important applications, in which halogen center dot center dot center dot halogen interactions have been successfully employed, are mentioned.

Automated summary

Halogen interaction is a controversial and important topic in crystal engineering and supramolecular chemistry, involving F, Cl, Br, and I. Lighter and heavier halogens behave differently, and the nature of the interaction depends on the atom covalently bonded to the halogens. This review discusses different types of homo-halogen, hetero-halogen, and halogen-halide interactions, their natures, preferred geometries, as well as various motifs and interchangeability with other functional groups. The review also mentions important applications of halogen interactions.