Nano chemistry : large molecular capsules and coordination networks based on self-assembly
This thesis focuses on the characterisation of supramolecular structures containing p-sulfonatocalix[ n]arenes (where n=4,5,6,8) with suitable guest molecules and lanthanide metal cations. The characterisation is based primarily on X-ray diffraction but high-resolution NMR techniques have also been used to identify p-sulfonatocalixarene/crown ether complexation in the solution phase. Notably, remarkable control can be achieved over the formation and geometries of nano-metre scale spheroids or tubules containing p-sulfonatocalixarene via guest selection. Chapter 1 gives a short overview of supramolecular chemistry, molecular recognition and the history and synthesis of calixarenes. The supramolecular chemistry of the p-sulfonatocalx[n]tilarenes and a selection of interesting and recently reported nano-metre scale multi-component supramolecular architectures are also reviewed. Chapter 2 describes the pH dependent formation of a number of molecular capsule and bi-layer supramolecular architectures based on p-sulfonatocalixarene, (di)aza-functionalised guest species and lanthanide metals. Chapter 3 describes the formation of several bi-layer structures based on p-sulfonatocalixarene and lanthanide, metals. Incorporation of different lanthanide metal salts changed the resulting structures by either inclusion or exclusion of the anions in the supramolecular architectures. Chapter 4 describes a series of Diffusion Ordered Spectroscopy experiments that were performed in collaboration with Dr. Julie Fisher at the University of Leeds. The experiments were based on calixarene/crown ether systems and the results showed 1: 1 host-guest complexation in solution with a series of charged species. Chapter 5 describes the formation of Russian doll complexes and the design and control over nanometre scale spheroidal arrays composed of p-sulfonatocalixarene. Chapters 6 and 7 describe the formation of novel supramolecular complexes that are based on the p-sulfonatocalix[5,6,8]arenes. The resulting supramolecular architectures include unprecedented bis-molecular capsules, coordination polymer chains and 3-D networks.