Halogen-Bonding-Driven Self-Assembly of Solvates of Tetrabromoterephthalic Acid

Halogen bonding is one of the most interesting noncovalent attractions capable of self-assembly and recognition processes in both solution and solid phase. In this contribution, we report on the formation of two solvates of tetrabromoterephthalic acid (H(2)Br(4)tp) with acetonitrile (MeCN) and methanol (MeOH) viz. H(2)Br(4)tp center dot 2MeCN (1(MeCN)) and H(2)Br(4)tp center dot 2MeOH (2(MeOH)). The host structures of both 1(MeCN) and 2(MeOH) are assembled via the occurrence of simultaneous Br center dot center dot center dot Br, Br center dot center dot center dot O, and Br center dot center dot center dot pi halogen bonding interactions, existing between the H(2)Br(4)tp molecular tectons. Among them, the cooperative effect of the dominant halogen bond in combination with hydrogen bonding interactions gave rise to different supramolecular assemblies, whereas the strength of the halogen bond depends on the type of hydrogen bond between the molecules of H(2)Br(4)tp and the solvents. These materials show a reversible release/resorption of solvent molecules accompanied by evident crystallographic phase transitions.