Catching Cations using Fused [n]Polynorbornanes

Cations are significant in all aspects of life. From the crucial role of spherical alkali metal cations in bodily function, to the harm that can be caused by heavy metal cations. Larger organic cations can also play important roles in industry and medicine. Some examples of this larger class are antimicrobial polymixins, the pesticide paraquat and cyclobis(paraquat), used in the study of electron transfer systems in mitochondria. Crown ethers, pioneered by Charles Pedersen in 1967, are macrocyclic polyethers. Their electron-rich interior can selectively bind with cations based on size. There have been some recent developments in the synthesis of ?staple-like? bis-crown ether hosts in which these larger frameworks are capable of binding larger organic cationic species. The problem with the design of these hosts is their tedious syntheses and inability to be synthesised to a desired length for the targeting of a specific guest. Fused [n]polyorbornanes are rigid, covalently bonded frameworks that can be synthesised to a discrete length by means of the Alkene, Cyclobutane Epoxide (ACE) reaction. The ACE approach has successfully been used for the synthesis of ?staple-like? functionalised fused [n]polynorbornanes for anion binding. The approach has yet to be used in the synthesis of ?staple-like? hosts for cation binding, with the only examples containing crown ethers, having a linear conformation. In this project, an investigation into the synthesis of a ?staple-like? bis-crown framework was conducted, with many of the important steps to synthesis being completed. While the final framework itself could not be synthesised, the research conducted lays the framework for future approaches to synthesis of the target compound.