Thesis (Ph. D.)--University of Chicago, Department of Chemistry, December 2002. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2005. / Elliot Chaikof, Committee Member ; Loren Williams, Committee Member ; David M. Collard, Committee Chair ; Andres J. Garcia, Committee Chair ; Marcus Weck, Committee Member.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Delaware, 2007. / Principal faculty advisor: Darrin J. Pochan, Dept. of Materials Science & Engineering. Includes bibliographical references.

Thesis (Ph.D.)--Ohio University, June, 2008. / Abstract only has been uploaded to OhioLINK. Includes bibliographical references (leaves 199-209)

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Syntheses, spectral, electrochemical and spectroelectrochemical studies of phenylthio and amino derivatised metallophthalocyanines complexes are reported. The complexes are immobilized onto a gold macro disk, gold ultramicroelectrode and gold coated fiber electrodes via self assembly with phenylthio MPc derivatives or onto a glassy carbon electrode via electropolymerisation with amino MPc derivatives. For the first time MPc SAMs were formed on gold coated fiber. The electrocatalytic behavior of the modified electrodes was studied for the detection of nitrite and L-cysteine, all modified electrodes showed improved electrocatalytic oxidation compared to the unmodified electrode. The MPc complexes catalyzed nitrite oxidation via a two-electron mechanism producing nitrate. Cobalt tetraaminophthalocyanine showed the best catalytic activity for nitrite oxidation in terms of overpotential lowering compared to other complexes and thus was used for nitrite detection in a food sample, the nitrite concentration was determined to be 59.13 ppm, well within the limit for cured meat products. Electrocatalytic oxidation of L-cysteine on SAM modified gold coated fiber was reported for the first time. The gold coated fiber and ultamicro cylinder electrode were less stable towards the electro-oxidation of cysteine compared to its oxidation on the gold disk. The gold disk electrode gave better catalytic performance in terms of stability and reduction of overpotential. The phenylthio cobalt phthalocyanine derivative gave the best catalytic activity for L-cysteine oxidation in terms of overpotential lowering compared to other phenylthio derivatized MPc complexes. The amount of L-cysteine in human urine was 2.4 mM, well within the urinary L-cysteine excretion range for a healthy human being.

The self-assembly of chiral amphiphilic molecules in aqueous solutions is of particular interest because the chirality of individual molecules is often expressed in their supermolecular structures. Self-assembled tubes made of chiral amphiphilic molecules represent useful supramolecular architectures which hold promise as controlled release vehicles for drug delivery, encapsulates for functional molecules, and nanoreactors for chemical reactions. Lithocholic acid (LCA) is a secondary bile acid with the concentration being identical to that of cholesterol in the hepatic bile and gallbladder. It has a rigid, nearly planar hydrophobic steroid nucleus, with four hydrogen atoms and one hydroxyl group directed toward the concave side, and the convex side with three methyl groups. The ionic head with a carboxyl group is linked to the steroid nucleus through a short alkyl chain. In this thesis work, I study the self-assembly behavior of LCA at the liquid-solid interface, in confined spaces, and bulk solution. We find that the initially formed LCA vesicles further assemble into fractal tubes on glass slides by diffusion-limited aggregation and pronglike tubes by the capillary flow generated in an evaporating vesicle solution confined by two parallel glass slides. While in bulk solution, the LCA vesicles linearly aggregate and fuse into spiral tubes at pH 12.0. The spiral tubes can transition into a straight shape as the pH of solution is reduced to 7.4. The shape transition of the tubes is reversible as the pH of solution is adjusted back to 12.0. The pH-switchable shape transition suggests that the self-assembled LCA tubes can act as a supramolecular chemical spring. Finally, the LCA tubes are endowed with optical functionality by embedding cadmium sulfide nanopaticles (CdS) in the tube walls by the co-assembling synthesis of cadmium sulfide iv (CdS) nanoparticles with lithocholic acid (LCA) molecules. The fluorescent composite tubes can undergo pH switchable spiral/straight, which are a promising system for a variety of materials and biological applications.

Different approaches to surface modification were investigated in this work on gold, glassy carbon, multi-walled carbon nanotube paper and on single-walled carbon nanotubes adsorbed on glassy carbon. These approaches include electrochemical grafting, electropolymerisation, click chemistry, axial ligation, adsorption and self-assembled monolayers. The modified surfaces were characterised using a variety of techniques; predominantly electrochemistry, scanning electrochemical microscopy and X-ray photoelectron spectroscopy. For the formation of self-assembled monolayers on gold, four new manganese(III) phthalocyanines (1a-d), octa-substituted at the peripheral position with pentylthio, decylthio, benzylthio, and phenylthio groups were synthesized and characterised. X-ray photoelectron spectroscopy was used to show the formation of a sulphur-gold bond. A number of approaches using 4-azidoaniline (2a) combined with azide-alkyne click chemistry and electrochemistry were also used to anchor ferrocene and pyridine moieties on to the carbon surfaces, including direct in situ diazotation and grafting, electropolymerisation, and the synthesis of the diazonium salt followed by grafting. Iron phthalocyanine was linked to the pyridine-clicked surfaces through axial ligation, where the strong axial bond formed by the interaction between the central metal and the lone pair of the nitrogen in the pyridine group resulted in stable modified electrodes. The potential of these surfaces for the detection of analytes such as thiocyanate, hydrazine and sulphite are briefly shown as well. This work also describes for the first time the possibility of performing local micro-electrochemical grafting of a gold substrate by 4-azidobenzenediazonium (2b) using scanning electrochemical microscopy in a single and simple one step approach, without complications from adsorption.

It’s becoming more and more difficult to make smaller, denser, and faster computer chips. There’s an increasing demand to design new materials to be applied in current lithographic process to get higher patterning performance. In this work, the aqueous developable single molecule resists were introduced, synthesized and patterned. A new group of epoxide other than glycidyl ether, cyclohexene oxide was introduced to functionalize a molecular core and 15 nm resolution was obtained. The directed self-assembly (DSA) of block copolymers as an alternative lithographic technique has received growing interest in the last several years for performing higher levels of pitch subdivision. A 3-step simplified process for DSA by using a photodefinable substrate was introduced by using a functionalized polyphenol with an energy switchable group and a crosslinkable group. Two high χ block copolymers PS-b-PAA and PS-b-PHEMA were successfully designed and synthesized via ATRP with controlled Mw and PDI. The size of the same PS-b-PAA polymer was tunable by varying the thermal annealing time. PS-b-PHEMA shows to be a suitable block polymer for the industry-friendly thermal annealing process. A self-complementary hydrogen-bonding urea group as a center group was used to facilitate the self-assembly of polymers. “Click” chemistry is promising for synthesis of PS-Urea-Urea-PMMA.