<p>The ability of gold(I) complexes to function as catalysts for myriad organic transformations has led to a dramatic increase in their utilization. Among the homogeneous reactions catalyzed by gold(I), carbon-carbon and carbon-heteroatom bond forming processes are of particular interest for the fields of organic synthesis and pharmaceutical development. Discussed herein are gold(I)-catalyzed methods for the intra- and intermolecular functionalization of alkenes, alkynes, and allenes with nitrogen- and oxygen-based nucleophiles leading to new C&#8210;X bonds (X = N, O).</p><p>Approximately 26 cationic gold &pi;-alkene complexes, containing either IPr [IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene] or P(t-Bu)2o-biphenyl ancillary ligands, were isolated or generated and six complexes were analyzed by X-ray crystallography. Spectroscopy, X-ray crystallography, and alkene binding studies are in accord with a gold&#8722;(&#960;-alkene) interaction dominated by &sigma;-donation from the alkene to gold. Kinetic analyses of degenerate isobutylene exchange in both the IPr and phosphine systems are consistent with associative pathways for isobutylene exchange involving cationic bis(alkene) intermediates.</p><p>Reaction of a 1:1 mixture of (L)AuCl [L = P(t-Bu)₂o-biphenyl or IPr] and AgSbF₆ with internal alkynes led to isolation of the corresponding cationic, two-coordinate gold &pi;-alkyne complexes in &#8805;90% yield. Equilibrium binding studies show that the binding affinities of alkynes to gold(I) are strongly affected by the electron density of the alkyne and to a lesser extent on the steric bulk of the alkyne. Treatment of a suspension of (IPr)AuCl and AgSbF₆ with terminal arylacetylenes led to the formation of thermally unstable gold &pi;-alkyne complexes of the form [(IPr)Au(eta<super>2</super>-HC&#8801;CAr)] SbF₆ in &#8805;86 ± 5% yield, which were characterized by spectroscopy without isolation. Warming these complexes to 0 °C led to C(sp)-H bond cleavage and formation of dinuclear gold(I) &sigma;,&pi;-acetylide complexes of the form {[(IPr)Au]₂(eta<super>1</super>,eta<super>2</super>-C&#8801;CAr)} SbF₆, three of which were isolated in 99% yield and one of which was characterized by X-ray crystallography.</p><p>A family of 7 cationic gold(I) &pi;-allene complexes were isolated and fully characterized in solution, and in three cases by X-ray crystallography. Degenerate intermolecular allene exchange kinetic studies for three of the allene complexes are in accord with a two-term rate law of the form rate = k1[complex] + k2[complex][allene] with with Gibb's free energy barriers of 17.4 - 18.8 kcal mol<super>-1</super> (1) and 15.2 - 17.6 kcal mol<super>-1</super> (2). Variable temperature NMR analysis of these complexes established facile intramolecular &#61552;-face exchange through &#61544;1-allene intermediates or transition states with barriers of 8.9 - 10.9 kcal mol<super>-1</super> for phosphine and 9.5 - 12.2 kcal mol<super>-1</super> for IPr complexes.</p><p>Mechanistic investigation of gold(I)-catalyzed intramolecular allene hydroalkoxylation established a mechanism involving rapid and reversible C-O bond formation followed by turnover-limiting protodeauration from a mono(gold) vinyl complex. This on-cycle pathway competes with catalyst aggregation and formation of an off-cycle bis(gold) vinyl complex.</p> / Dissertation

This research focuses on the microwave properties of nanoparticles for use as contrast and hyperthermia agents. Currently, visible light is used for irradiation of nanoparticles as hyperthermia agents. Additionally, visible/Near-infrared light is used for photoacoustic tomography (PAT) imaging. Compared to optical wavelengths, frequencies in microwave range transmit through tissue with high penetration depth . Thus, deep cancerous cells and malignant tissue may be treated and imaged. These nanoparticles could enable the use of a hybrid microwave/acoustic technique known as thermoacoustic tomography. Here, quantitative measurements of the heat generation in super paramagnetic iron oxide nanoparticle (SPIONs), gold nanoparticles (AuNPs), and gold nanoclusters (AuNCs) induced by microwave energy at 3 GHz, are presented and compared. Based on our experiments, SPIONs are the most efficient nanoparticles for microwave heating. Very high concentrations of SPIONs are able to convert microwave energy into heat about 22° C more than DI-water. AuNPs, which support plasmon resonances, do not provide heat under microwave irradiation as predicted by our computational analysis based on Mie Theory. AuNCs are a new form of ultra-small (<2.5 nm) AuNPs which do not support plasmonic resonances and have supra-molecular properties such as sub-conduction band transitions. Interestingly, AuNCs have the potential to absorb microwave energy and may provide an alternative to SPIONs. These nanoparticles had not yet been studied before in this frequency region. In addition, the absorption coefficient of nanoparticles were calculated using complex permittivity data from a dip probe kit and a Vector Network Analyzer (VNA) in a broad band range from 500 MHZ to 10 GHz. This method allows identification of best frequency region with highest penetration depth. In the last step, the nanoparticles with different concentrations were tested as exogenous contrast agents in a Thermoacoustic Tomography (TAT) system. TAT utilizes the penetration depth of microwave energy while producing high resolution images through acoustic waves. The addition of an exogenous contrast agent improves image quality by more effectively converting microwave energy to heat. The experiment reveals that the time resolved thermoacoustic signal (TA) from SPIONs is stronger than AuNPs and AuNCs and thus, the image contrast produced by SPIONs is stronger than the two other aforementioned nanoparticles.

Includes bibliographical references (p. 241-252) and index. / xxiii, 263 p. ill., maps 23 cm

Bibliography: leaves 233-260. / xxi, 260, [30] leaves : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Uses the late-orogenic, structurally-controlled Junction gold deposit near Kambalda, Western Australia, to examine the potential of soil-gas geochemistry as an exploration vector in an environment where mineralisation is present, but no ore-related trace elements are detectable in the near-surface regolith. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics 1999

No description available.

No description available.

No description available.

No description available.

No description available.

Thesis (M. Sc.) (Hons.) -- University of Western Sydney, Nepean, 1998. / Thesis submitted for the degree of Master of Science (Honours) in the University of Western Sydney. Bibliography : p. 100-105.