Foldamers Based On Oligopyrroles And Their Property Studies

The regular folding of biological macromolecules is a magical phenomenon in nature,and plays a special and important role in life activities.For example,DNA and RNA with helical structure are the transmitters of genetic code and biological information of life.Their structures not only reflect the aesthetics of nature everywhere,but also are essentially the result of non-covalent forces,especially hydrogen bond.Inspired by the nature,helical foldamers based on hydrogen bond,?-? interaction and hydrophobic effect have been synthesized in recent years.They usually have relatively flexible structures and form a certain size of cavity or channel,which provides a potential platform for guest recognition,transmembrane transport and other fields,and attracts extensive attention of scientists.Among them,helical foldamers are very interesting for the recognition and transmission of water molecules with important physiological significance.Water is the basic substance to maintain the normal physiological activities of organisms,and plays an inestimable key role in numerous physiological and chemical reactions.Recent studies have shown that the content of bound water in brain,bone,muscle,skin and other tissues changes with age.Many age-related diseases are directly related to the water content in the corresponding tissues.Accordingly,scientists have proposed that maintaining the water content in tissues is a new method to cure diseases such as Alzheimer.Unfortunately,it is difficult to study the behavior and binding mode of water molecules in biological macromolecules through existed technologies and means.Therefore,it is important to study the recognition of water molecules by artificial helical foldamers for understanding complex biological water binding behavior.In this paper,a seseries of oligopyrroles foldamers were designed and synthesized,and their properties were studied.In detail,the dissertation is divided into three chapters:In chapter 1,the research progress of aromatic foldamers are introduced.The foldamers based on hydrogen-bond and metal coordination are highlighted.Finally the applications of aromatic foldamers in guest recognition were summarized,and the research progress and significance of water binding by foldamers are discussed in detail.In chapter 2,we describe syntheses of a series of oligo(pyrrole-pyridine)foldamers obtained via Pd-catalyzed Suzuki coupling.The solid and liquid structures of foldamers were characterized by NMR,MS and X-ray single crystal diffraction analyses.At the same time,the water binding behavior of foldamers was systematically studied.In chapter 3,the synthesis of linear oligopyrroles were explored.The preparation of the precursors required for the syntheses of oligopyrroles are also explained including their characterizations.Further our attempts to incorporate a naphthyridine unit instead of pyridine moiety into the foldamer backbone are discussed.The latter modification was proposed with an anticipation that,it would lead to an increase in the helical diameter which presumably could be tested for recognition of guest molecules of different size.