Anion Receptors and Transporters for Biomedical Applications

Abstract

This thesis reports on the design and synthesis of three different series of novel anion receptors developed to address challenges currently facing anion binding and anion transport chemistry.

The first project analyses an initial series of four non-fluorinated anion receptors. These compounds contain four pendant arms, producing a variably encapsulating binding site from four directional hydrogen bonding (thio)urea motifs. A further eight fluorinated tetrapods were then synthesised to analyse the effects of fluorination on the anion binding, anion transport, and transport mechanism properties of the more encapsulating scaffold.

The second project builds on a previously reported tetralactam scaffold, which bound anions inside a macrocyclic binding cavity. Substitution of the central isophthalamide and the peripheral heterocyclic rings with various electron-withdrawing groups produced a series of tetralactams that were analysed for their Cl– and F– binding and transport properties. Only Cl− binding affinities were observed due to increased size selectivity and binding strength for F–. The series produced extremely high levels of transport activity for both Cl– and F– via an electroneutral H+/Cl− co-transport mechanism.

The third project details a series of novel halogenated and non-halogenated ferrocene-containing macrocycles, the ferrocenoyl tetralactams, were developed and tested for their initial electrochemical, anion binding, and anion transport properties. The electrochemical properties of the series were then investigated to analyse the stability and reversibility of the reduction and oxidation processes and study the electrochemical effects of the different linker groups.