Extension, adaptation and application of folding oligoaramides
Sanford, Adam R
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The basic chemistry and properties of our oligoaramide foldamers being established by previous members of this group, notably Dr. Huaqiang Zeng, made it possible for further expansion of these systems. This thesis demonstrates various extensions and adaptations of the helically folding motif and variants thereof from: (1) induction of chirality, both intermolecularly and intramolecularly, (2) use as hosts for biologically relevant guests, (3) improved efficiency toward achieving polymeric species and (4) extension of the established chemistry to similar systems. Several different building blocks and oligomeric foldamers were generated. From the synthetic work, specific handedness was achieved through the use of chiral side chains and the introduction of chiral guests as discussed in Chapter 3. Our folding oligoaramides were found to undergo chirality amplification in the presence of small quantities of the chiral guest arginine methyl ester. The amplification effect is substantially reduced as the molar ratio of host to guest approaches one. The ability to distinguish the two enantiomers of the amino acid arginine via their distinctive Cotton effects may lead to unique sensing devices based on these porous foldamers. The tunability of these systems as specific binders for guanidinium alkyl guanidines and arginine methyl ester were explored in Chapter 4. Oligomers from hexameric macrocycles to full turn crescent oligoamides were found to specifically bind with guanidinium analogs based on the arrangement of the amide oxygens in the interior cavities. Generation of high molecular weight polymeric materials with hollow interior cores was unsuccessful (Chapter 5), but lessons learned from the process lead to the generation of a new class macrocycles (Chapter 6), novel self-assembling nanotubes and the discovery of a new class of helically folding "poly"aramides (Chapter 7).