Thesis (Ph. D.)--University of Oregon, 2004. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 213-252). Also available for download via the World Wide Web; free to University of Oregon users.

M.Sc. / This dissertation describes the synthesis and characterization of CdSe/ZnO and Ag/ZnO core/shell nanoparticles using water as a solvent. The effects of the concentration of the shell precursor, pH, and stabilizing agents on the properties of the nanoparticles were investigated. In general, the type of capping agents had an influence on the crystallite size of the core nanocrystals. The particle size distributions which were calculated from TEM images show that thioglycolic acid as a capping agent produced larger particle sizes compared to thioglycerol. For example, thioglycolic acid produced on average 5.0 nm CdSe nanoparticles while 4.0 nm average CdSe particle size was obtained when using thioglycerol as stabilizer. This observation was confirmed by UV/Vis absorption results which showed that thioglycerol capped CdSe NCs exhibited excitonic peaks positioned at lower wavelength than thioglycolic capped CdSe NCs. XRD results showed that the capping agents used in the current work had no influence upon crystal structure of the CdSe nanocrystals as the cubic structure was obtained with both stabilizers. The effect of shell precursor concentration at pH 12 showed heterogeneous formation of ZnO nanoparticles at high shell precursor concentrations. Various ZnO morphologies including nanoflowers and nanotriangles were observed on TEM images when 50 mL and 25 mL of zinc nitrate solution were used as shell precursors. UV/Vis absorption results also confirmed the presence of ZnO absorption peaks for samples prepared with 50 mL and 25 mL of zinc nitrate solution as shell precursors. PL results showed an increase in peak intensity as a function of precursor volumes. XRD results showed diffraction patterns due to the wurtzite structure of ZnO. CdSe diffraction patterns in these samples were not detected by the XRD instrument. At low volume of the shell precursor, which was 5 mL of 0.05 M zinc nitrate, TEM results showed that spherical CdSe/ZnO core/shell nanoparticles were obtained at pH 12 with 5 mL of 0.05 M zinc nitrate solution and 0.1 M sodium hydroxide used as shell precursor solutions, and thioglycerol as a stabilizer. XRD analysis of the v sample exhibited ZnO diffraction patterns and the CdSe patterns were not detected owing to their low peak intensities compared to those of the ZnO. Similar results were obtained when thioglycolic acid was used a stabilizing agent. However, TEM images showed the hexagonal shape of the CdSe/ZnO core/shell nanoparticles. The pH level was found to influence the photoluminescence properties of the CdSe/ZnO core/shell nanoparticles. The enhanced PL intensity was obtained with CdSe/ZnO core/shell nanoparticles with pH 9 in comparison with CdSe/ZnO core/shell nanoparticles prepared at pH 12. TEM images showed the presence of a thin ZnO shell on the surface of CdSe cores for CdSe/ZnO prepared at pH 9 which could be attributed to the PL enhancement. Although EDS results confirmed the presence of elements such as Cd, Se, Zn and O for both the CdSe core and ZnO shell, the XRD results confirmed the presence of only CdSe diffraction patterns, which suggested the ZnO shell had low peak intensity or was amorphous. A similar effect of these capping agents was observed for Ag nanoparticles as thioglycerol produced average particle size of 16.0 nm whereas 31.0 nm as the average particle size was obtained with thioglycolic acid as stabilizing agent. The crystal phase of Ag NPs was independent of the type of stabilizer. The Ag NPs precipitated in face centred cubic phase. Core/shell Ag/ZnO nanoparticles were produced with 5 ml of zinc nitrate as shell precursor. Higher volumes (50 ml and 25 ml) of zinc nitrate shell precursor induced heterogeneous precipitation of ZnO nanoparticles. XRD patterns confirmed peaks due to ZnO and Ag for Ag/ZnO core/shell nanoparticles.

The successful application of Tppts, and its derivatives, in biphasic transition metal-catalysed reactions opened up a new field of chemistry requiring a rational design of water-soluble ligands. The main objective of the research described in this dissertation was the preparation and the application of new water-soluble phosphine ligands. The ligands were prepared by the use of carbon nucleophiles and chlorophenylphosphine derivatives. The carbon nucleophiles included malonate derivates, which were subsequently reduced to the di-alcohols and were transformed into water-soluble phosphines by the reaction with 1,4-butanesultone. Secondary and tertiary malonate nucleophiles were used and the steric demands of compounds containing more than one malonate group were investigated. Various attempts to obtain water-soluble compounds from dimalonate phosphine oxides failed. TBDMS-protected aryl halides were also used as nucleophiles. One (or two) of these silyl ethers was reacted with chlorophenylphosphine derivatives and after deprotection with TBAF the compounds were made water-soluble by a reaction with 1,4-butanesultone. The hydrogenation of arylphosphine oxides to form cyclohexylphosphine oxide derivatives was also investigated. However, these cyclohexylphosphines were more easily obtained by the reaction between the previously mentioned carbon nucleophiles and chlorocyclohexylphosphine derivatives, which were freshly prepared. A series of cyclohexyl-containing water-soluble phosphines was prepared in this way. The oxygen sensitive nature of phosphines lead to two different approaches in the reaction route: the phosphines were either borane protected followed by a subsequent deprotection step, or the phosphines were allowed to oxidise and were reduced back to the free phosphine at a later stage. The efficiency of both approaches in the reaction routes was examined. The deprotection of phosphine-boranes was performed using various “new” deprotecting reagents and the borane-species and free phosphines were separated using water/organic extractions. The various extraction coefficients of the amine-borane complexes were determined. The newly prepared ligands were used in a variety of palladium-catalysed reactions as well as in the hydroformylation of 1-octene employing rhodium. The reactions were performed in both neat organic solvents as well as mixtures between water and DMF or toluene and the results were compared to the use of Tpp and Tppts. It was found that many of the new ligands afforded superior yields compared to those of Tpp and Tppts. In the last part of the study, various diphenylphosphinic amides were used as DoM-groups. Sec- and tert-BuLi were used together with a variety of electrophiles to facilitate ortho-substitution on either one or two rings on the amides. This was seen as a start of a new approach towards functionalised phosphine ligands. / Prof. D.B.G. Williams

M.Sc. (Chemistry) / An aqueous, simple, environmentally friendly synthetic method for the preparation of water-soluble CuS and CdS semiconductor nanoparticles has been developed. Different capping agents with active functional groups (-COOH, -NH and -OH) namely, alanine, glucuronic acid and thioglycolic acid, have been employed in the preparation copper sulfide (CuS) and cadmium sulfide (CdS) semiconductor nanoparticles as capping molecules. These capping agents were explained in Chapter 3 and 4. The reported nanoparticles display good optical and structural properties. The semiconductor nanoparticles were easily synthesized at low temperatures employing low cost materials. In Chapter 3 colloidal methods were used to develop CuS and CdS nanoparticles from metal acetate as a stabilizing agent at different low temperatures. The effect of temperature on the growth and solubility of nanoparticles was investigated. The absorption spectra of all samples prepared were blue shifted as compared to their bulk materials which signify small particles size. Water-soluble alanine-capped CuS and CdS semiconductor nanoparticles were obtained. The alanine-capped CuS in the form of rods, triangular and spherical like shaped with single crystal phase were successfully attained. Chapter 4 describes the uses of the acids, glucuronic and thioglycolic acids, as capping ligands. The glucuronic acid molecules were found to be the effective ligands to render solubility of the nanoparticles. Solubility tests revealed that both glucuronic acid-capped CuS and CdS nanoparticles were more soluble in water as compared to thioglycolic acid-capped CuS and CdS nanoparticles. In Chapter 5 sulphonated porphyrins were prepared and explored in combining them with nanoparticles. The results obtained from 1H NMR suggest that the porphyrins were sulphonated. The sulphonated porphyrins were conjugated with the water-soluble nanoparticles and this is described in Chapter 6. The results presented in Chapter 6 are in favour of the formation of nanoparticle-porphyrin complexes.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 150-159). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 150-159). Also available on the Internet.

Thesis (Ph. D.)--University of Oregon, 2000. / Title from title screen. Paging within document: xvii, 167 p. : ill. Includes vita and abstract. Includes bibliographical references (p. 149-167).

Thesis (Ph. D.)--University of Oregon, 2000. / Includes vita and abstract. Includes bibliographical references (p. 149-167). Also available for download via the World Wide Web; free to University of Oregon users.

Adviser: Kenneth M. Doxsee. xvii, 167 p. / A print copy of this title is available through the UO Libraries under the call number: SCIENCE QD412.M7 B35 2000 / The chemistry of three organometallic systems in water was studied with the goal of understanding more fully the reactivity of organometallic complexes in aqueous environments. Molybdocene complexes were found to catalyze C-H bond activation reactions in water. The catalytically active solutions were prepared from the molybdocene dimer [Cp

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 240-150). Also available on the Internet.