Columnar assembled pyridyl bis-urea macrocycles 1 provide a strong 1D supramolecular synthon to construct hierarchical assemblies. These 1D pillars contain ditopic symmetrical acceptors in the form of basic oxygen lone pairs. Herein, we probe this synthon with a series of activated halogen bond donors, the regio-isomers of diiodotetrafluorobenzenes, which vary the relative orientation of the halogen bond formers. Irrespective of the initial stoichiometry, each donor only formed one type of co-crystal with 1. In each case, similar strong pillars of assembled 1 were observed that organize the donors through the CO⋯I interaction, which were significantly shorter than the sum of the van der Waals radii of the atoms involved and among the shortest reported for neutral organic molecules. X-ray photoelectron spectroscopy characteristic core level shifts strongly indicated the formation of halogen bonding interactions.These studies suggest that this synthon can utilize both hydrogen and halogen bonding orthogonally to build complex structures.
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