Supramolecular nanotubes based on halogen bonding interactions: cooperativity and interaction with small guests.

In this manuscript we study the formation of a series of self-assembled supramolecular nanotubes (SNTs) governed by noncovalent halogen bonding interactions. We have used eight different belts to construct the nanotubes, which are based on alternating benzene rings with 4-X-pyridine or p-X-benzonitrile rings (X = Br, I). The orientation of the halogen atoms can be parallel (denoted as "all up") or antiparallel (denoted as "up/down"). In addition to the calculation of the formation energies of several binary and ternary assemblies, we have studied the ability of these non-covalently bonded self-organizing nanotubes to incorporate both anions and cations in their interior. We have used the BP86-D3/def2-TZVP level of theory to analyse the large assemblies and the RI-MP2/def2-TZVP level of theory for some model systems. This research emphasizes the role of σ-hole halogen bonds in the design and generation of assembled supramolecular structures and offers an approach for the creation of SNTs.