Self-assembly of resorcinarenes

Abstract

The synthesis and X-ray structural studies of 33 novel solid-state complexes of resorcinarenes with alkyl ammonium cations were carried out together with selected solution and gas phase studies. Alkyl resorcinarenes are versatile building blocks in supramolecular chemistry due to their often concave shape and possession of multiple interaction sites for both hydrogen bonding and π interactions. Among other assemblies, resorcinarenes have been known to form dimeric and hexameric hydrogen bonded supramolecular capsules. In this thesis the encapsulation properties of unsubstituted alkyl resorcinarenes and complexation of alkyl ammonium cations were studied in detail. Special emphasis has been placed on the effect of the size and charge of the encapsulated guest molecule on the outcome of the assembly in solid state. In addition to the willingly forming dimeric capsular structures, open complexes and intriguing novel type of resorcinarene nanotubes were also achieved. The hollow crystals of the nanotubular assembly exhibit remarkable thermal stability and can be used to exchange and store small solvent molecules. The solid-state structures were complemented with studies of the interactions between the host resorcinarene and guest cation in solution by NMR, where 1:1 complexes were observed, and in the gas phase by mass spectrometry, where dirneric capsules were also detected. The literature section of this thesis contains a brief introduction to supramolecular chemistry and self-assembly. The complexation and self-assembling properties of resorcinarenes, and especially the capsule formation of alkyl resorcinarenes are reviewed. Due to the limitations on the scope of this thesis the focus is on the reported solid state structures.