Supramolecular rods via halogen bonding-based self-assembly of fluorinated phosphazene nanopillars

A cyclotriphosphazene derivative bearing six 4-iodotetrafluorophenyl-substituted arms self-assembles with dipyridyl derivatives under the control of (NI)-I-... halogen bonding to give rise to complexes where the starting modules are present in a 1:3 stoichiometric ratio, respectively. The directionality of the (NI)-I-... halogen bonding translates the pillar-like arrangement adopted by the cyclotriphosphazene module into the rod-shaped supramolecular structure of the formed infinite chains. The invariance of (NI)-I-... interactions translates the different size of the used dipyridyl modules into different pitches along the self-assembled rods. The obtained supramolecular architectures show a remarkable structural similarity confirming the reliability of halogen bonding in the design of complex supramolecular networks.