Date of Award
Campus Access Dissertation
Chemistry and Biochemistry
Linda S Shimizu
Organic self-assembled materials have great utility as sensing materials, in gas storage, in separations, and as electronic devices. These assembled materials are typically held by non-covalent interactions such as hydrogen bonds, pi-pi stacking and dipole-dipole interactions. We are interested in developing supramolecular macrocyclic self-assemblies that could be utilized for a variety of applications. A bis-urea phenylether macrocycle self-assembled into columns and could serve as a `nanoreactor' to form host:guest complex with small molecules such as methylstyrene, divinylbenzene and iodine; a larger macrocycle with phenylethynylene pyridine space has also been synthesized as a precursor for Metal Organic Frameworks (MOFs) or sensing materials.
We also designed a stilbene containing bis-urea macrocycle that exhibited unusual photochemical properties. This macrocycle undergoes a stereoselective photo-cycloaddition reaction with a quantitative yield. Substitution of the urea group for a carbonate group afforded a macrocycle that displays similar photochemistry. The carbonate macrocycle is of particular interest due to the fact that it self-assembles into column through C-H---O hydrogen bonds. Photocycloaddition and hydrolysis of this carbonate macrocycle yields a tetra-alcohol structure that could act as a rigid build block for more complex organic structure or MOFs.
Conjugated microporous polymers (CMPs) have been the subject of many recent chemical and material developments. While these polymers are typically amorphous, we designed a diacetylene containing tetra-amide macrocycle that self-assembles into columns through amide hydrogen bonding. External energy sources (heat or UV irradiation) initiate the polymerization along the column readily to give conjugated macrocyclic polydiacetylenes (PDAs). The materials before and after topochemical reaction both exhibit open cavities as crystalline microporous materials. The polymerized material has been investigated as potential sensor for small organic compounds. A larger diacetylene macrocycle with phenylether spacer has been also approached.
Xu, Y.(2011). Functional Materials From Self-Assembled Macrocycles. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/748