Supramolecular assemblies and modes of binding of the 1,6-hexanedipyridinium ion and the HCl salt of N,N′-bis(3-pyridylmethyl)-diaminoethane, with the symmetrically substituted tetramethylcucurbit[6]uril

The molecular binding behaviour of the symmetrically substituted tetramethylcucurbit[6]uril (TMeQ[6]) was examined in relationship to the two pyridine-based molecular guests 1,6-hexanedipyridinium dication (Hdipy2+) and the HCl salt of N,N′-bis(3-pyridylmethyl)-diaminoethane (Ediamp). The interactions and binding modes of each guest with TMeQ[6] are discussed using solution results (1H NMR spectroscopy) and solid-state findings (single-crystal X-ray diffraction), to evaluate interactions in common. Supramolecular structures are formed that rely on a combination of the now typical driving forces associated with Q[n] as a molecular host, which are dipole–ion, hydrophobic, H-bonding and in the present examples include π…π and C–H…π interactions.