Halogen bonding in conducting or magnetic molecular materials

The role of halogen bonding interactions in conducting or magnetic molecular systems is evaluated here in various series of halogenated radical molecules, such as neutral nitroxides or tetrathiafulvalene (TTF) salts where short and linear C-Hal...Hal,O,N interactions are identified. Oxidation of halogenated TTFs to the cation radical state activates the halogen bonding interaction with counter ions of Lewis base character, i.e. halide, polyhalide or halometallate anions on the one hand, and polycyanometallate or organic nitrile anions on the other. Iodoperfluoroalkanes or -perfluorarenes can also act as halogen bond donors when associated with neutral nitroxide radicals or with halide anions in cation radical salts of non-halogenated TTFs.