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

Abstract

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.

Keywords:

• tetramethylcucurbit[6]uril
• 1,6-hexanedipyridinium dication
• N,N′-bis(3-pyridylmethyl)-diaminoethane
• self-assembled
• binding modes

Acknowledgements

We acknowledge the support of the National Natural Science Foundation of China (No. 20662003), the International Collaborative Project of Guizhou Province (No. 2007400108), the Foundation of the Governor of Guizhou Province and also the UNSW@ADFA start-up grant scheme.