PhD - Biochemistry There are 9 files which have been withheld at the author's request / A systematic investigation into the effect that alkyl and aryl substituents have on the ethene polymerisation behaviour of a series of MAO co-catalysed mono-substituted bis-(cyclopentadienyl)zirconium dichloride and bis-(indenyl)zirconium dichloride metallocenes was carried out. The electronic attributes of the substituents were related to the Hammett substituent functions. The sizes of the ligands were measured from the perspective of the metal using the Tolman cone angle, numerical solid angle and analytical solid angle methodologies. For the mono-substituted cyclopentadienyl metallocenes of formula (CpR)2ZrCl2 (R = Me, Et, iPr, tBu, SiMe3, CMe2Ph), it was found that an optimum ligand size (R = Et, iPr) was required for high activity. These substituents protected the active polymerisation site from deactivation processes. However, if the substituent was too bulky (R = tBu, CMe2Ph) activity dropped drastically. Electronic factors possibly also play a role as demonstrated by the much higher activity of the SiMe3 substituted catalyst over its similarly sized tBu analogue. A series of new bis-(indenyl)zirconium dichloride metallocenes of formula [2–R-Ind]2ZrCl2 (R = H, Me, SiMe3, Ph, Bz and 1-Naphthyl) and [1–R-Ind]2ZrCl2 (R = Me, Et, iPr, tBu, SiMe3, Ph, Bz and 1-Naphthyl) were synthesised. Ethene polymerisation reactions with these metallocenes revealed the same electronic and steric trends observed for the (CpR)2ZrCl2 catalysts. Steric effects were found to play an important role with polymerisation activity decreasing as the size of the substituent increases. Also, the 1-substituted metallocenes had higher activities than their 2-substituted analogues, the differences in their activity increasing with the size of the substituent. By studying the conformations adopted by the indenyl ligands in the solid state, we have rationalised this phenomenon to be a result of the greater steric protection afforded to the active polymerisation site by the 1-substituted metallocenes.

Electrogenerated chemiluminescence (ECL) studies were performed on several interesting compounds. A series of silole-based (silacyclopentadiene) chromophores was examined to understand the effects of their structure on the electrochemistry and spectroscopy of these compounds. A case was observed in which high steric hindrance improved ECL by inhibiting internal conversion and protecting radicals from secondary reactions. Another case was observed in which steric effects induced a rotation in the silole substituents, increasing secondary reactions and lowering quantum efficiency ([Phi subscript PL]). Spiro-FPA, which consists of two DPA centers, exhibits excimer formation despite high steric hindrance, due to its ability to form di-ions, which have a greater electrostatic attraction to one another than mono-ions. The compound (dppy)BTPA is a highly solvatochromic, boron-containing chromophore that was examined in a variety of solvents. Of note is the emission in pure acetonitrile, which is prominent in the ECL spectrum, but barely visible in the photoluminescence. Finally, B⁸ amide, a compound based on the laser dye, BODIPY, was examined. It exhibited unusual ECL characteristics. These include a strong, long-wavelength emission and transients that are clearly visible for 20 min or more, but display dramatically varying light intensities with each pulse. Evidence for the contribution of a film formed with the oxidation product is presented. Additionally, ECL simulations are performed using a general physics software package to better understand some of the observed phenomena.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1933. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed June 14, 2010) Includes bibliographical references (p. 68-62) and index (p. 63-64).

No description available.

No description available.

Abstract Twenty-seven phosphine and six bipyridine ligands were synthesised and characterized. Additionally, a new route to the family of phosphine ligands via o-thioanisyldichlorophosphine was found. The phosphine ligands contain thiomethylphenyl, methoxyphenyl, dimethylaminophenyl, pyridyl, naphthyl and anthracenyl groups, and the bipyridine ligands thiomorpholine and piperidine groups. Metal complexes of 3-pyridyldiphenylphosphine, 6,6'-bis(methylthiomorpholine)-2,2'-bipyridine and 4,4'-dimethyl-6,6'-bis(methylthiomorpholine)-2,2'-bipyridine were prepared. Ligands and complexes were characterized by 1H-, 13C-, 31P- and two-dimensional HSQC-NMR spectroscopy, and crystal structures were determined for the ligands and two of the metal complexes. Tertiary phosphine ligands were prepared for catalytic purposes and tested in hydroformylation reaction at the Helsinki University of Technology and the University of Joensuu. Bipyridine ligands were designed for bimetallic coordination. The phosphine ligands cover a wide range of electronic and steric properties. The spectroscopic parameters and crystal structures were studied with the purpose of charting trends in the basicities and steric effects of the ligands.

We have reacted several derivatives of the anticancer drug cisplatin with N-acetyl-Lcysteine (N-AcCys) and N-acetyl-L-methionine (N-AcMet), which are two of the primary amino acid targets of platinum. NMR spectroscopy was used to monitor the reactions and determine the effect the different ligands would have on the platinum reactivity. Several of the platinum compounds were tested at pH of 4 and 7, and with platinum:amino acid ratios of 1:1, 2:1 and 1:2. Competition reactions between cysteine and methionine were done to confirm which would react with the platinum compound first. [Pt(dien)(NO3)]+ reacts faster with methionine than with cysteine at both pH 4 and 7 at a 1:1:1 ratio. [Pt(N,N,N',N',N"-pentamethyldiethylenetriamine)(NO3)]+ reacts with methionine faster at pH 4 but with cysteine faster at pH 7. This is most likely due to the thiol in the cysteine starting to deprotonate around pH 7. [Pt(Me4en)(NO3)2] (Me4en = N,N,N',N'-tetramethylethylenediamine) forms several products with N-AcCys at both pH 4 and 7, with the amounts of the products varying depending on the ratio of platinum and Cys. Mass spectrometry indicated one product as {[Pt(Me4en)(H2O)]2(N-AcCys)}2+, with two platinum compounds coordinated to a single cysteine. Lastly Pt[(en)(NO3)2] when reacting with N-AcCys at a ratio of 1:1 will coordinate with 2 different Cys molecules. With an excess of Pt the complex prefers to bind to only 1 Cys.

iv, 191 leaves : ill. (some in end pocket) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Organic Chemistry, 1980

Thesis (Ph.D.) -- University of Adelaide, Dept. of Organic Chemistry, 1980.