| Abstract [eng] |
The emerging field of supramolecular chemistry is centered around the design and creation of complex dynamic multi-molecular structures, drawing inspiration from various biochemical systems and processes. One group of supramolecular systems are the cavitands – molecules or multi-molecular scaffolds featuring a discrete internal cavity that is capable of forming host-guest complexes with smaller molecular guests. Many potential and practically applied applications for such systems have been found in chemistry, biochemistry, materials science and medicine. However, currently synthetically available cavitands have many problems, including difficult preparation, limited selection of cavity size and geometry, small functionalization capability and high symmetry. This thesis describes a novel system for preparation of geometrically diverse cavitands from a variety of monomeric building blocks, and presents a proof-of-concept synthesis of a supramolecular tetrameric “Swiss cross” shaped cavitand. The system is based on the use of the bicyclo[3.3.1]nonane structure, which, when fused with aromatic linkers, allows for semi-rigid, 90°-angled chiral carcasses to be obtained. When both enantiomers of the chiral bicyclononane[3.3.1]-2,6-dione are used, positive and negative curvature can be incorporated, allowing for control of the spatial structure of the resulting carcasses. Appending 2-ureido-4-pyrimidinone motifs to the termini of the carcasses allows for self-complimentary hydrogen bonding, resulting in the formation of cyclic oligomeric structures in non-polar solvents. In this thesis, a novel method for the preparation of both pure enantiomers of bicyclononane[3.3.1]-2,6-dione in decigram scale is presented. The synthesis of C2-symmetric Friedländer synthon N-(4-amino-5-formyl-2-(hydroxymethyl)phenyl)-4-methylbenzenesulfonamide has been optimized to allow for operationally simple and high-yielding decagram-scale synthesis. These building blocks were used to prepare the “Swiss cross” shaped cavitand monomer. Aggregation into tetrameric structures in CDCl3 was confirmed by NMR methods, however, the poor solubility of the resulting structure prevented more in-depth studies and highlighted the need for modified iterations featuring increased solubility in organic solvents of various polarities. The final part of the thesis described the design and development of bicyclononane[3.3.1]-2,6-dione derivatives featuring various functional groups that may serve as universal linkers, allowing for easy late-stage modification with various structures that would allow for fine-tuning of solubility characteristics. |
