Halogen-bonding complexes based on bis(iodoethynyl)benzene units: A new versatile route to supramolecular materials

Iodoalkynes [1,4-bis(iodoethynyl)benzene (p-BIB) and 1,3-bis(iodoethynyl) benzene (m-BIB)] have been used successfully to prepare halogen bonding complexes with a range of 4-pyridine derivatives showing liquid crystalline organizations. The trimeric halogen-bonded complexes obtained from p-BIB have a rod-like structure and exhibited high order calamitic phases (SmB and G). In contrast, m-BIB gives rise to bent-shaped structures that display SmAP-like mesophases. Furthermore it was found that the presence of three and five aromatic rings in these halogen-bonding complexes promotes calamitic mesophases while seven rings are required to stabilize bent-core mesophases. The formation of halogen bonding in the complexes was confirmed by several techniques, including FT-IR, XPS, and single crystal X-ray diffraction and the strength of the bonds was evaluated by DFT calculations © 2013 American Chemical Society.This work was financially supported by MICINN-FEDER of Spain-EU (Projects MAT2009-14636-C03-01, MAT2011-27978-C02-01, CTQ2012-35692 and MAT2012-38538-C03-01) and Aragón Government-FSE (Project E04). The authors acknowledge the Spanish Government for a JAEDoc-CSIC contractPeer Reviewe