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Functionalized platinum (II) and gold (I) acetylide complexes: structural and spectroscopic properties andanticancer activitiesShum, Yuen-ting., 岑婉婷. January 2007 (has links)
published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy
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MEASUREMENT OF HYPERFINE STRUCTURE IN DEUTERATED ACETYLENES VIA MOLECULAR-BEAM MICROWAVE SPECTROSCOPY.TACK, LESLIE MARTIN. January 1982 (has links)
This work describes the measurement of hyperfine structure in a series of deuterated acetylenes via molecular-beam microwave spectroscopy. Measurements of spin-rotation constants were used to calculate the paramagnetic contribution to the chemical shielding of the concerned nucleus. Where possible, comparisons with NMR measurements were made. Measurements of the deuterium quadrupole coupling determined in this work are compared with previous measurements on the same or similar systems. A review of the theoretical work done in this area is presented as well as a discussion of trends observed from high precision measurements of deuterium quadrupole coupling. A computer program that calculates hyperfine structure for up to four coupling nuclei of arbitrary spin is presented.
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The Synthesis and Reactivity of Bis(silyl)acetylenesAlbanesi, Todd E. (Todd Edward) 05 1900 (has links)
Six bis(silyl)acetylenes with the following varied silicon substituents were prepared: I (Me, Me); II (H, H); III (Cl, H); IV (Cl, Cl); V (OMe, H); VI (OMe, OMe). While I and II may be prepared by the reaction of dilithio- or bis(bromomagnesium)-acetylide with appropriate chlorosilane, similar reactions designed to give III - VI give oligomers, YMe_2Si(C≡C-SiMe_2)_nY, VII, Y = Cl, OMe, as the major products indicating that the acetylenic functionality on silicon activates the chlorosilane toward nucleophilic substitution. Compounds III and IV were prepared by free radical chlorination of II. Methanolysis of III and IV gave quantitative yields of V and VI, respectively. In the presence of mineral acid, VI readily cyclized to give high yields of the cyclic siloxane octamethyl-4,9-dioxa-3,5,8,10-tetrasila-cyclodeca-1,6-diyne, VIII, and the analogous triyne, IX. It was determined that V and VI could be prepared directly from II in high yield by methanolysis with palladium catalyst. Vaska's complex also accomplished the conversion. I attempted to prepare bis(ethoxydimethylsilyl)acetylene by using of Wilkinson 's catalyst for hydrosilylation with acetaldehyde. The principal product of this reaction was 1-(dimethylsilyl)-3,5,5-trimethyl-4-oxa-3-silacyclopent-1-ene, XI.
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The influence of secondary treated effluent on denitrification in a natural wetlandBrodrick, Stephanie J., n/a January 1985 (has links)
The influence of effluent addition on denitrification potential in the
Thredbo Wetland was observed by comparing an area of the wetland
receiving secondary treated effluent with another area receiving no
effluent addition.
Physico-chemical measurements (Eh, pH and temperature) of the soil were
conducted in both sampling areas to characterise the denitrifying
environment. Levels of nitrate plus nitrite and ammonium ion in the
soil from 0-30cm depth were recorded on a seasonal basis to identify the
role of effluent addition and vertical distribution of inorganic nitrogen species in controlling the distribution of denitrification
potential in the soil.
Denitrification potentials of soils and decaying plant material were
evaluated by the acetylene blockage technique. This involved laboratory
incubations under optimum conditions of pH, temperature, nitrate
concentration, carbon supply, and diffusion. The influence of these
physico-chemical factors on denitrification was also investigated.
It was found that the effluent addition caused higher denitrification
potential in soils and surface decaying plant material by raising soil
temperature, lowering Eh, and increasing concentrations of nitrate plus
nitrite and ammonium ions. The highest denitrification potential was
recorded in the decaying plant material on the soil surface. The highest
soil denitrification potential occurred in the 0-6cm depth segment.
Carbon supply and pH had no influence on denitrification potential
whilst low temperature (5ºC), and restricted diffusion limited
denitrification.
In terms of tertiary water treatment denitrification in Thredbo Wetland
makes a significant-contribution to the removal of nitrogen year-round.
However, total nitrogen removal could be increased by increasing the
residence time of water in the wetland thereby encouraging greater
spatial and temporal interaction between the denitrifiers and the
wastewater nitrogen.
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Functionalized platinum (II) and gold (I) acetylide complexes structural and spectroscopic properties and anticancer activities /Shum, Yuen-ting. January 2007 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
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Description globale de la structure de vibration-rotaton de la molécule d'acétylène / Global description of the vibration-rotation structure of the molecule of acetyleneRobert, Séverine 04 June 2009 (has links)
Afin de progresser dans la compréhension de la structure de vibration-rotation de l'acétylène dans son état électronique fondamental, un modèle global a été développé avec succès pour trois de ses isotopologues, permettant d'attribuer de nouvelles données de spectres enregistrés sous diverses conditions expérimentales. L'ensemble des programmes d'analyse rovibrationnelle globale conçus à l'Université Catholique de Louvain par le Pr. A. Fayt et al. ont été utilisés pour répondre aux demandes de collaborateurs tels que les Prs. A. Campargue, A. Jolly ou encore R. Georges dans le cadre de plusieurs problèmes de type spectroscopique, notamment pour des applications astrophysiques. Le modèle global et son pouvoir prédictif mis ainsi à l'épreuve, nous avons démontré la validité de nos jeux de paramètres pour ces trois molécules.
Concernant l'isotopologue principal, $H^{12}C^{12}CH$, 14 nouvelles bandes ont été mises à jour à partir de spectres enregistrés en CRDS à Grenoble par A. Campargue et al. Une analyse rovibrationnelle globale a été effectuée jusqu'à une énergie de 8600 cm$^{-1}$. 10750 raies ont été ajustées simultanément sur les 12137 attribuées dans la littérature. 266 paramètres ont été déterminés par la méthode de moindres-carrés. La déviation standard sans dimension du fit est de 0.92. La bande $
u_{5}$-$
u_{4}$, centrée vers 117 cm$^{-1}$ a été simulée. La valeur du moment de transition associé, $|mu_{5 leftarrow 4}|$, a été estimé à partir des informations existant dans la littérature exploitant par ailleurs les résultats issus du modèle global.
163 nouvelles bandes du $H^{12}C^{13}CH$ ont été analysées bande par bande à partir de spectres enregistrés sur BOMEM DA3.002 FT à Bologne et sur FTS IFS120HR à Bruxelles. Les spectres enregistrés ont été analysés région par région, produisant ainsi plus de 8300 raies de rotation-vibration non encore répertoriées. Elles enrichissent une base de données qui a servi à effectuer une analyse rovibrationnelle globale jusque 9500 cm$^{-1}$. 16250 raies ont été ajustées sur les 18010 disponibles. 317 paramètres ont été déterminés dans le processus de moindres-carrés. La déviation standard sans dimension du fit est de 1.1.
Le troisième isotopologue qui a retenu notre attention est le $H^{12}C^{12}CD$. La découverte de cette molécule dans l'atmosphère de Titan a orienté notre travail. Lors de l'analyse globale des niveaux de bending, 4347 raies ont été fittées à l'aide des 62 paramètres endéans la précision expérimentale de 5 10$^{-4}$ cm$^{-1}$. La déviation standard sans dimension du fit est de 0.79. Une simulation des niveaux de bending avec un profil de raie associé a été effectuée permettant la création d'une base de données spectroscopiques contenant 7472 raies et destinée aux astrophysiciens.
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X-ray Photoelectron Spectroscopy and Kinetic Study: Pt-Group Metals and Bimetallic SurfacesGath, Kerrie K. 14 January 2010 (has links)
Pt-group metals were some of the first metals to be studied as catalysts
for industrial use. The goal of these studies was to ascertain a fundamental
understanding of CO oxidation and acetylene cyclotrimerization reactions on Ptgroup
metals. A further goal was to determine the optimal conditions for each
reaction.
CO oxidation on Rh(111),Pt(100), and Pd(100) was scrutinized on various
oxide surfaces from chemisorbed to bulk metal oxides. Low pressure reactions
on Rh(111) reveal the highest activity was a CO uninhibited surface with <1ML of
chemisorbed oxygen. Pt(100) high pressure oxidation revealed that only <1ML
oxygen is formed during high pressures reactions. High pressure CO oxidation
reactions on Pd(100) show oxygen penetration after CO has been consumed;
however, during the highest activity XPS found only chemisorbed species.
The cyclotrimerization of acetylene to benzene is another reaction found
in industry typically carried out on Pd. The active site is considered to be a 7 atom configuration with 6 atoms surrounding a central atom. By adding
relatively catalytically inert Au atoms to the active Pd(111) surface the acetylene
coupling activity is enhanced. Cyclization activity is a function of the surface
composition and the surface structure. A single Pd atom surrounded by six Au
atoms is found to have the highest activity at 300K for acetylene
cyclotrimerization.
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Addition reactions of some substituted indoles with dimethyl acetylenedicarboxylate and methyl propiolate /Choi, Chi-keung, Michael. January 1983 (has links)
Thesis--Ph. D., University of Hong Kong, 1983.
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Addition reactions of some substituted indoles with dimethyl acetylenedicarboxylate and methyl propiolate蔡志強, Choi, Chi-keung, Michael. January 1983 (has links)
published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy
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Selective Hydrogenation of Acetylene over Pd, Au, and PdAu Supported NanoparticlesWalker, Michael 17 December 2013 (has links)
The removal of trace amounts of acetylene in ethylene streams is a high-volume industrial process that must possess high selectivity of alkyne hydrogenation over hydrogenation of alkenes. Current technology uses metallic nanoparticles, typically palladium or platinum, for acetylene removal. However, problems arise due to the deactivation of the catalysts at high temperatures as well as low selectivities at high conversions.
Pore expanded MCM-41 is synthesized via a two-step strategy in which MCM-41 was prepared via cetyltrimethylammonium bromide (CTMABr) followed by the hydrothermal treatment with N,N-dimethyldecylamine (DMDA). This material was washed with ethanol to remove DMDA, or calcined to remove both surfactants. PE-MCM-41 based materials were impregnated with palladium, gold, and palladium-gold nanoparticles. The removal of DMDA had an effect on both the conversion and selectivity, in which they were found to drop significantly. However, by using the bimetallic PdAu catalysts, higher selectivity could be achieved due to increased electron density.
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