| Summary: | Fabrication of functional supramolecular structures requires a certain degree of control
which may not be achieved by relying solely on noncovalent interactions. The current study
aims to investigate the effect of a rigid cavitand template on morphology, function and stability
of lipophilic G-quadruplexes. The first Chapter of this thesis introduces different aspects of G
quadruplex chemistry and explains how these structures are particularly suited for the creation of
supramolecular architectures.
The second Chapter of this thesis presents the synthesis and self-assembly of a new class
of supramolecular architectures composed of four guanosines attached to a rigid cavitand
template. These structures, named template-assembled synthetic G-quartets (TASQs), were
synthesized via the “click” reaction and manifest an ordered topology dictated by the template.
The lipophilic TASQs were found to self-associate spontaneously to form a singular basket-like
structure in chloroform. Moreover, it was found that TASQs form cation-free G-quartets which
exhibit remarkable stability under this condition.
The third Chapter of this thesis describes the preparation, characterization and solution
study of the cation-bound complexes TASQNa⁺, TASQK⁺, TASQCs⁺, and TASQSr²⁺.
Cations play a major role in controlling the morphology and stability of G-quadruplexes. The
analysis of the cation-specific structures of TASQs reveals the formation of a monomeric G
quartet for Na⁺ and Sr²⁺,a dimeric system for Cs⁺ and a mixture of monomers and dimers for K⁺.
The factors governing the formation of these structures were evaluated, the selectivities of
TASQs for cations were determined, and the cation-dependent structural transformations were
studied.
The fourth Chapter describes the efforts towards synthesizing a hydrophilic TASQ via
the “click” reaction. The following steps have been taken: 1) a water-soluble cavitand has been
successfully synthesized and characterized, which can potentially serve as a hydrophilic
template, and 2) two oligonucleotides have been appropriately functionalized and preliminary
coupling reactions were attempted. The next phases of this research along with potential future
directions are discussed in Chapter five.
|
|---|
