Halogen bonding in metal–organic–supramolecular networks

Halogen bonding (XB) has been recently exploited as a significant tool for engineering crystals involving coordination and organometallic compounds as tectons. This review, in particular, focuses on extended networks based on XB between electron donor groups bound to metals and halo-pyridine and halo-tetrathiafulvalene moieties as electron acceptors. The influence of XB over the structures and the interactions between the organic frameworks and the metal centers is highlighted. The chemistry of some mononuclear systems forming XB is described in terms of tools for controlling supramolecular arrangement and chemical behaviour. Various computational studies on the energy of XB at different levels of sophistication, their advantages and limits concerning the evaluation of the interaction energy and modelling of its origin are critically surveyed. Modelling of a new example of interaction between Cp2MH2 (M = Mo, W) and CF3I is reported together with the description of the electron density of the complex analyzed in terms of the Quantum Theory of Atoms in Molecules (QTAIM) model.