Thesis (Ph.D.) - University of St Andrews, May 2009. / Restricted until 11th May 2011.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Greg O. Sitz. Vita. Includes bibliographical references.

Techn. Universiẗat, Diss., 2002--Berlin.

Techn. University, Diss., 2004--Berlin.

The main objective of this investigation was to study palladium-catalyzed coupling of 2-aryl-4-chloro-3-iodoquinolines with phenyl boronic acid in order to assess the regioselectivity of carbon-carbon bond formation at either C3 or C4. The 2-aryl-4- chloro-3-iodoquinolines were subjected to Pd(PPh3)4-catalyzed coupling reaction with phenyl boronic acid in DMF in the presence of 2M sodium carbonate (aq) to afford 2,3-diaryl-4-chloroquinolines. Reaction of 2,3-diaryl-4-chloroquinolines with sodium methoxide in MeOH-DMF mixture under reflux afforded the corresponding 2,3-diaryl-4-methoxyquinoline. An alternative route to the latter involving palladiumcatalyzed cross-coupling reaction of 2-aryl-3-iodo-4-methoxyquinolines derived from the reaction of 2-aryl-4-chloro-3-iodoquinolines with sodium methoxide in refluxing methanol-THF mixture was also investigated. The 2,3-diaryl-4-methoxyquinolines were subjected to further studies of chemical transformation with boron tribromide to afford the corresponding 2,3-diarylquinolin-4(1H)-ones. All new compounds were characterized using a combination of NMR (1H and 13C), IR and mass spectroscopic techniques as well as elemental analysis. / Chemistry / M. Sc. (Chemistry)

No description available.

abstract: Water-soluble, adenosine triphosphate (ATP)-stabilized palladium nanoparticles have been synthesized by reduction of palladium salt in the presence of excess ATP. They have been characterized by electron microscopy, energy dispersive X-ray spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and X-ray diffraction in order to determine particle size, shape, composition and crystal structure. The particles were then subsequently attached to a glassy carbon electrode (GCE) in order to explore their electrochemical properties with regard to hydrogen insertion in 1 M sodium hydroxide. The particles were found to be in the size range 2.5 to 4 nm with good size dispersion. The ATP capping ligand allowed the particles to be air-stable and re-dissolved without agglomeration. It was found that the NPs could be firmly attached to the working electrode via cycling the voltage repeatedly in a NP/phosphate solution. Further electrochemical experiments were conducted to investigate the adsorption and absorption of hydrogen in the NPs in 1 M sodium hydroxide. Results for cyclic voltammetry experiments were consistent with those for nanostructured and thin-film palladium in basic solution. Absorbed hydrogen content was analyzed as a function of potential. The maximum hydrogen:Pd ratio was found to be ~0.7, close the theoretical maximum value for β phase palladium hydride. / Dissertation/Thesis / M.S. Chemistry 2013

Prof. A. Roodt

No description available.

>Magister Scientiae - MSc / This thesis reports on the syntheses of new bimetallic iminopyridyl nickel(II) and palladium(II) complexes as catalyst precursors for ethylene ligomerization/polymerization. Tetrahydrophenyl-linked iminopyridyl ligands, pyridin-2-ylmethyl-{4-[(pyridin-2-ylmethylimino)-methyl]-benzylidene}-amine (L1) and (2-pyridin-2-yl-ethyl)-{4-[(2-pyridin-2-yl-ethylimino)-methyl]-benzylidene}-amine (L2) were prepared via condensation from terephthaldehyde and 2 molar equivalents of a primary pyridylamine. Alkyl-linked iminopyridyl ligands N,N'-bis-pyridin-2-ylmethylene-propane-1,3-diamine (L3), N,N'-bispyridin- 2-ylmethylene-butane-1,4-diamine (L4) and N,N'-bis-pyridin-2-ylmethylenepentane- 1,5-diamine (L5) were prepared by condensation of 2 equivalents of 2- pyridinecarboxaldehyde and a primary diamine. The ligands were obtained as either red oils or orange solids. These ligands were characterized using Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), mass spectrometry (MS), elemental analysis (EA), ultraviolet-visible spectrophotometry (UV-Vis) and thermal gravimetric analysis (TGA) where applicable. The tetrahydrophenyl-linked iminopyridyl ligands were subsequently used to prepare their corresponding homobimetallic palladium(II) and nickel(II) complexes. A 1:2 reaction of the ligands with PdCl2(COD), NiCl2(DME) and NiBr2(DME) gave palladium(II) and nickel(II) complexes C1-C6 in moderate to very good yields (58-94%). The palladium(II) complexes were found to be stable, but light-sensitive solids while the nickel(II) complexes were found to be stable, but light and air sensitive solids. These complexes were characterized using FTIR, NMR, EA, MS, UV-Vis and TGA. These complexes were then tested for catalytic activity of ethylene oligomerization. It was found that complexes C1 and C5 were highly active when activated by the cocatalysts methylaluminoxane (MAO) as well as ethyl aluminium dichloride (EADC). It was found that EADC gave the highest activity so the remaining catalysts (C3 and C6) were tested exclusively with EADC. All four complexes were active for ethylene oligomerization with yields of between 2.7-6.5 g, with C5 providing the highest activity and C1 the lowest. These catalysts were highly selective towards C4 oligomers with percentages ranging from 71-81%. Optimization studies were then carried out with C3 by varying the pressure and Al:Ni ratio.