Dissertation (Ph.D.)--University of Toledo, 2007. / Typescript. "Submitted as partial fulfillment of the requirements for the Doctor of Philosophy degree in the Engineering Science Concentration in Chemical and Environmental Engineering." Bibliography: leaves 213-221.

Thesis (Ph. D.)--Washington State University. / Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Michael J. Krische. Vita. Includes bibliographical references.

No description available.

Ph.D. (Chemistry) / Please refer to full text to view abstract

The interaction between short oligodeoxynucleotides of specific sequence with cisplatin, cis-Pt(NH₃)₂Cl₂, has been examined under single stranded and duplexing conditions by ¹H nuclear magnetic resonance (NMR) spectroscopy. The oligonucleotides were synthesized by a modified phosphotriester technique adapting procedures initially used in oligoribonucleotide synthesis. The oligo sequences were designed to favour the intrastrand cis-Pt(NH₃)₂[d(-GpXₙpG-)-N7(l),N7(n+l)] crosslink, where X was up to three thymine units. Variable pH NMR was used to determine the site of platination on the oligomer. Variable temperature NMR was used to determine changes in base stacking and duplex formation resulting from oligomer platination. In the short oligomers, the intrastrand cisplatin crosslink formed between terminal guanines resulted in the internal section of the sequence being bulged out of a normal stacking orientation. The chemical shifts of the guanine H-8 resonances indicated that platination caused one of the guanine bases to flip from the normal anti geometry into a more syn-like orientation. This was observed for the three oligomers examined (X=thymidine, n=1,2,3). Variable temperature NMR of exchangeable imino protons in the oligomers with larger loops (n=2,3), indicated that the loop region of the complex was a random coil and that water access to the loop was restricted. i i i Longer sequences were examined which contained the cis-Pt(NH₃)₂[d(GpXₙpG)-] complex as well as external nucleotide units, 3' and 5' to the platinated region. Platination disrupted intrastrand base stacking of nucleotides externally adjacent to the platinum complex. Complementary and partially complementary sequences were examined under duplexing conditions. Stabilities, reflected in the Tₘ of the duplex, of fully complementary hexamer, heptamer and octamer oligomer mixtures were obtained by variable temperature NMR. Changes in duplex stability resulting from oligomer sequence and length along with the nature of the duplex to coil transition were discussed. Imperfect duplexes, designed to mimic the loop structures formed in platinated oligomers, indicated that the duplex containing one extra core thymine formed a helix resembling the fully complementary hexamer duplex with the extra base stacked out of the helix. With the core of the duplex containing two thymine units and one opposing complementary adenine, both thymines stacked into the helix with the adenine oscillating between the two thymines. When the oligomer mixture contained two extra thymine units with no opposing complements, duplex formation was not observed. A comparison between the duplex to coil transition in normal and imperfect duplexes was discussed. Similar duplex experiments were carried out using the platinated oligomer sequences. In each case examined, aggregation of the platinated strand, coupled with the oligomer sequences employed contributed to the failure of duplex formation. / Thesis / Doctor of Philosophy (PhD)

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

No description available.

M.Sc. / Polymerization of a-olefins by metallocene-based catalysts, is an ever expanding field with current scientific research continuing in an endeavor to develop chiral catalysts with greater stereospecificity and activities. However, the application of metallocene catalysts in oligomerization reactions of a-olefins has been somewhat neglected. This is despite the fact that metallocene catalysis can offer a convenient route to the synthesis of higher a-olefin oligomers. Furthermore, by utilizing an assortment of functional group transformations, a-olefin oligomers can serve as intermediates for a variety of specialty chemicals. Notwithstanding the possibility of employing alternative ligands in catalysis, the use of non-cyclopentadienyl-based complexes is a topic that has only recently been considered. Comparative studies of a series of analogous complexes is lacking in this field and thus a pertinent study of a number of known metallocene complexes was executed in this project. Furthermore, an industrially applicable process for oligomerization was sought after. This was in fact achieved by subjecting the a-olefins 1-pentene, 1- hexene and 1-octene, to oligomerization conditions with a previously unreported and lowered methylaluminoxane ratio. This reaction proved to be highly selective to dimer formation of the three aforementioned higher a-olefins. In order to gain more insight into the oligomerization process, the progress of the reaction was also followed. Only zirconium complexes were synthesized and furthermore, the induction of oligomerization as opposed to polymerization (using compounds known to be active solely as polymerization catalysts), was attempted by increasing the reaction temperature. The second part of this project entailed the synthesis and subsequent testing of zirconium catalysts containing non-cyclopenatadienyl-based ligands. These complexes have frameworks with chelating phenolate or naphtholate ligands. These complexes were tested for oligomerization, but results proved to be negative.

by Raymond Chi-Yuen Kwong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 60-62). / Acknowledgements --- p.i / Abbreviations --- p.ii / Abstract --- p.iii / Chapter 1. --- Introduction --- p.1 / Chapter 2. --- Synthetic Methodology for Arylenevinylenes --- p.12 / Chapter 3. --- Result and Discussion --- p.15 / Chapter 4. --- Conclusion --- p.42 / Chapter 5. --- Experimental --- p.43 / Chapter 6. --- References --- p.60 / Chapter 7. --- Spectra