Polymeric fibres, films, coatings and moulded products are ubiquitous in modern society, and are used in applications as diverse as packaging materials, clothing, medical devices, etc. Mechanistic and kinetic considerations are useful in the development of efficient catalysts for controlled selective polymerisations, which is essential for the production of polymeric materials possessing properties tailored to suit their application. Mercury-based compounds are used as catalysts in many applications of the synthesis of polyurethanes such as the production of polyurethane elastomers. Due to the environmental impact of mercury, there is a need to replace such catalysts with complexes based on benign metals. Group 4 metals are an attractive option, both in terms of reactivity and their benign environmental nature. A series of novel complexes have been synthesised, fully characterised, and their activity and selectivity investigated in a model reaction. The molecular structures of a number of potential catalysts have been determined by single crystal X-ray diffraction experiments. These potential catalysts have been screened in the model reaction utilising in situ reaction monitoring in order to acquire kinetic data. A method to study catalyst selectivity has also been developed. The results of these kinetic and selectivity studies are presented in this thesis and compared to the industrial phenylmercury neodecanoate catalyst system. A selection of well-defined complexes which have been synthesised as part of this body of work have also been evaluated in the preparation of polyurethane elastomers. Physical characterisation techniques such as Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA) and Scanning Electron Microscopy (SEM) have been used for this purpose.

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Metal alkoxides have been known for many years. Recently, a renewed interest in these compounds has arisen as they have been found to be viable precursors for metal oxide film synthesis. Lead zirconium titanate(PZT) films have shown promise for many applications in the electronics industry. Chemical vapor deposition(CVD) of PZT thin films has been hampered by the lack of a suitable zirconium precursor for low temperature chemical vapor deposition. Currently, both zircbnium alkoxides and zirconium β-diketonate complexes are employed in the CVD process of PZT films. The alkoxides, although volatile are moisture sensitive and are not easily handled under normal atmospheric conditions. Tetrakis β-diketonate complexes of zirconium are more stable than the alkoxides, but they have a deposition temperature that is too high for commercial use. A mixed (β-diketonate)zirconium alkoxide compound could provide the necessary stability while maintaining the volatility necessary for low temperature CVD. From the above reasoning, it was decided to prepare a zirconium di-(2,2,6,6 tetramethyl-3,5 heptadione) di-tert-butoxide compound. The compound was characterized and subjected to a variety of volatility studies. Thermogravimetric analysis provided evidence that the compound was volatile enough to be used in thin film synthesis. Initial attempts at film deposition, however, resulted in no film growth. Changing deposition parameters also resulted in no film growth. Visual inspection of the residue left after the deposition trials gave the first indication that the compound had undergone some change. Analysis of the material left in the reactor suggested the formation of a zirconium cluster compound. Further decomposition studies also resulted in the formation of the same zirconium cluster compound. Attempts to make the compound more stable at deposition temperatures centered on changing the alkoxide. Tri-tert-butyl alcohol(tritox) was prepared, however, the synthesis of the tritox - β-diketonate zirconium complex was unsuccessful. Other changes involved using pivalic acid to replace the alkoxide. Reactions with pivalic acid and zirconium di-(2,2,6,6 tetramethyl-3,5 heptadione) di-tert-butoxide resulted in the decomposition of the starting material. Other β-diketonate complexes were also investigated. Compounds synthesized from 2.4 pentadione(Acac), 1-benzoyl acetone(Bzac) and dibenzoyl methane(Dbzm) could not be purified in order to subject them to chemical vapor deposition. A zirconium complex with two different β-diketonate ligands was also synthesized. The complex was not investigated as a precursor for chemical vapor deposition because the isomers of the complex could not be separated. / Master of Science

No / Group IV metal complexes have previously shown promise as novel anticancer agents. Here, we discuss the mechanistic and cytotoxic nature of a series of group IV b-diketonate coordination complexes. Clear evidence that the ligands are exchangeable on the metal centre and that the b-diketonate ligands can act as potential drug delivery vehicles of the group IV metal ions was obtained. When evaluated for the cytotoxicity against human colon adenocarcinoma (HT-29) and human breast adenocarcinoma (MCF-7) cell lines, a general trend of decreasing potency down the group IV metals was observed. The most promising results obtained were for the hafnium complexes, with the tris diphenyl b-diketonate hafnium complex exhibiting IC50 values of 4.9 0.9 mm and 3.2 0.3 mm against HT-29 and MCF-7, respectively, which are comparable with the activity of cisplatin against the same cell lines. This tri b-diketonate hafnium complex is the first to show potent in vitro cytotoxic activity. The results reported show that ligand design has a significant effect on the cytotoxic potential of the complexes, and that these group IV complexes warrant further evaluation as novel metal-containing anticancer agents.

Yes / Herein, we report 31 new β-diketonate titanium compounds of the type [Ti(O,O)2X2], whereby O,O = asymmetric or symmetric β-diketonate ligand and X = Cl, Br, OEt or OiPr. Thirteen new crystal structures are discussed and show that these octahedral species all adopt cis geometries in the solid state. These compounds have been tested for their cytotoxicity using SRB and MTT assays, showing several of the compounds are as potent as cisplatin against a range of tumour cell lines. Results also show the [Ti(O,O)2Br2] complexes are more potent than [Ti(O,O)2Cl2], [Ti(O,O)2(OEt)2] and [Ti(O,O)2(OiPr)2]. Using a simple symmetrical heptane-3,5-dione (O,O) ligand bound to titanium, we observed more than a 50-fold increase in potency with the [Ti(O,O)2Br2] (28) when compared to [Ti(O,O)2Cl2] (27). One of the more potent compounds (6) has been added to three different sixmers of DNA, in order to analyse the potential DNA binding of the compound. NMR studies have been carried out on the compounds, in order to understand the structural properties and the species formed in solution during the in vitro cell assays.

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The syntheses and characterization of the palladium complexes [Pd(accp)2] (7), [Pd(acch)2] (8), [Pd(η3-CH2CMeCH2)(accp)] (11), [Pd(η3-CH2CMeCH2)(acch)] (12), [Pd(η3-CH2CtBuCH2)(accp)] (13) and [Pd(η3-CH2CtBuCH2)(acch)] (14) (accp = 2-acetylcyclopentanoate; acch = 2-acetylcyclohexanoate) are reported. These complexes are available by the reaction of Haccp (2-acetylcyclopentanone) and Hacch (2-acetylcyclohexanone) with Na2[Pd2Cl6] forming 7 and 8 or with [(Pd(η3-CH2CRCH2)(μ-Cl))2] (9, R = Me; 10, R = tBu) forming 11–14. The molecular structures of 7, 8 and 14 are discussed. Complexes 7 and 8 consist of a square-planar coordinated Pd atom with two trans-positioned bidentate β-diketonate ligands. The asymmetric unit of 14 exhibits one molecule of the palladium complex and a half molecule of water. The thermal behavior of 7, 8 and 11–14 and their vapor pressure data were investigated to show, if the appropriate complexes are suited as CVD precursors for palladium layer formation. Thermogravimetric studies showed the evaporation of the complexes at atmospheric pressure upon heating. The vapor pressure of 7, 8 and 11–14 was measured by using thermogravimetric analysis, giving vapor pressure values ranging from 0.62 to 2.22 mbar at 80 °C. Chemical vapor deposition studies were carried out applying a vertical cold wall CVD reactor. Either oxygen or forming gas (N2/H2, ratio 90/10, v/v) was used as reactive gas. Substrate temperatures of 350 and 380 °C were utilized. With 11–14 dense and conformal as well as particulate palladium films were obtained, as directed by SEM studies, whereas 7 and 8 failed to give thin films, which is probably attributed to their high thermal stability in the gas phase. For all deposited layers, XPS measurements confirmed the partial oxidation of palladium to palladium(II) oxide at 380 °C, when oxygen was used as reactive gas. In contrast, thin layers of solely metallic palladium were obtained utilizing forming gas during the deposition experiments. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

This PhD thesis deals with the activation of diorganozinc compounds by asymmetric catalysts in the framework of their enantioselective addition on carbon oxygen and carbon nitrogen double bonds. The properties of several new catalysts systems were investigated. Several chiral sulfonamido alcohols derived from (S)-leucinol and (1S) 3 aminoisoborneol were synthesized to cover a range of electronic and steric properties. These were evaluated in the addition of Et2Zn to N phosphinoyl and N sulfonyl-imines, but they did not provide any acceptable yields or enantioselectivities while used in stoichiometric quantities. Their catalytic properties were also investigated for the addition of Et2Zn to benzaldehyde. Unfortunately, only modest enantiocontrol (max. 47% ee) could be obtained with 10mol% of chiral ligand. We investigated another approach based on the possible activation of the nucleophilicity of dialkylzinc compounds towards benzaldehyde by fluoride anion. The combination of stoichiometric amount of an inorganic fluoride salt and a substoichiometric amount of a phase transfer catalyst (10mol% of crown ether 18 C 6) provided non-negligible rate acceleration. However, an asymmetric version of this catalytic system was not considered. Following our discovery of the activation provided by the fluoride anion, metal fluoride complexes were tapped as potential catalysts. In particular, copper(I) fluoride complex, (Ph3P)3CuF, was shown to accelerate the reaction on benzaldehyde. After screening a range of ligands, the combination of (Ph3P)3CuF and chiral BINAP in catalytic amounts (1mol%) was found to catalyze efficiently the Et2Zn addition on aromatic aldehydes. Yields were good but enantiocontrol was modest (49-63% ee). An improved copper fluoride-based catalyst was developed by combining a copper salt, a fluoride source and a chiral diphosphine ligand. Optimization of this second generation catalyst was carried out (copper source, fluoride source, chiral ligand, relative stoichiometries of catalyst's precursors, catalyst's loading, solvent, temperature) and applied to a range of aldehydes (upto 87% ee). A mechanism was proposed based on literature data and experimental observations. The influence of the counterion was then thoroughly explored by assessing the catalytic potential of various copper complexes in combination with chiral BINAP in the Et2Zn addition to benzaldehyde. Copper(II) diketonates provided good enantiocontrol (upto 88% ee) which could be improved even further by using optically active copper diketonates in a matched combination with chiral BINAP (upto 91% ee). This new system was applied to control the addition of Et2Zn to a range of aldehydes with a low catalyst loading (0.5mol%). A mechanism was proposed to explain a series of experimental observations. / Cette dissertation traite de l'activation de composés diorganozinciques par des catalyseurs asymétriques dans le cadre de leur addition énantiosélective sur des doubles liaisons carbone-oxygène et carbone-azote. Les propriétes de divers catalyseurs originaux ont été investiguées. Plusieurs sulfonamidoalcools chiraux dérivés du (S)-leucinol et du (1S) 3 aminoisoborneol ont été synthétisés pour couvrir un domaine de propriétés électroniques et stériques. Ceux-ci ont été testés lors l'addition du Et2Zn sur les N phosphinoyl et N-sulfonyl-imines, mais ils n'ont pas fourni de rendements et excès énantiomériques intéressants malgré leur utilisation en quantité stoechiométrique. Leurs propriétés catalytiques ont également été examinées dans le cadre de l'addition de Et2Zn au benzaldéhyde. Malheureusement, un faible contrôle de l'énantiosélectivité (max. 47% ee) est obtenu en présence de 10mol% de ligand chiral. Une autre approche abordée concerne l'influence de l'anion fluorure sur la nucléophilie des composés dialkylzincs envers le benzaldehyde. La combinaison de quantités stoechiométriques d'un sel fluoré inorganique et d'une quantités sub stoechiométrique d'un agent de transfert de phase (10mol% éther couronne 18 C 6) conduit à un accroissement non négligeable de la vitesse de réaction. Toutefois, le développement d'une version asymétrique de ce système n'a pas été considéré. A la suite de notre découverte de l'activation due à l'anion fluorure, les complexes métalliques fluorés ont été examinés en tant que catalyseurs potentiels. En particulier, le complexe du cuivre, (Ph3P)3CuF, accélère la réaction d'addition du Et2Zn sur le benzaldéhyde. Après un criblage de divers ligands, la combinaison de (Ph3P)3CuF et de la diphosphine chirale BINAP en quantité catalytique (1mol%) conduit à une catalyse efficace de l'addition du Et2Zn sur des aldéhydes aromatiques. Les rendements obtenus sont bons, par contre l'énantiosélectivité est modeste (49-63% ee). Une version améliorée de catalyseurs cuivre-fluorure a été obtenue en combinant un sel de cuivre, une source de fluorure et une diphosphine chirale. L'optimisation de divers paramètres de réaction a été effectuée (source de cuivre, origine de l'anion fluorure, ligand chiral, stoechiométries relatives des précurseurs du catalyseur, charge de catalyseur, solvant et température). Le catalyseur optimisé a été appliqué à divers aldéhydes (jusqu'à 87% ee). Un mécanisme réactionnel a été proposé sur la base d'arguments de la littérature et d'observations expérimentales. Le rôle du contre-ion a été exploré par un examen attentif de divers complexes du cuivre en combinaison avec la BINAP chirale en tant que catalyseurs de l'addition du Et2Zn sur le benzaldehyde. Les dicétonates du cuivre(II) ont conduit à une bonne énantiosélectivité (jusqu'à 88% ee) qui a pu être améliorée en utilisant des dicétonates du cuivre(II) optiquement actifs assortis avec le bon énantiomère de la BINAP (jusqu'à 91% ee). Ce nouveau système a été appliqué pour l'addition du Et2Zn sur divers aldéhydes avec une charge réduite en catalyseur (0.5mol%). Un mécanisme a été proposé afin de supporter les observations expérimentales.

Die vorliegende Arbeit befasst sich mit neuartigen Kupfer(I)- und Ruthenium(II)-komplexen und deren Verwendung als CVD-/ALD-Precursoren. Die Synthese Lewis-Basen-stabilisierter Kupfer(I)-β-Diketonat- bzw. -Carboxylat-Komplexe des Typs [LnMX] (M = Cu(I), X = Acetylacetonat, Iminopentenolat, Carboxylat; L = Phosphan PR3, Phos-phit P(OR)3; R = einbindiger, organischer Rest) standen hierbei im Vordergrund. Verbin-dungen des Typs [(PR3)MX] dienten als Ausgangsverbindungen zur Darstellung einkerni-ger Komplexe mit σ Donorliganden. Durch die Wahl der Lewis-Base sowie des β-Diketonato- bzw. Carboxylato-Fragmentes war es möglich, Einfluss auf die Eigenschaften der erhaltenen Komplexe zu nehmen. Somit waren auch die Untersuchung der thermischen Eigenschaften sowie das Abscheideverhalten der Komplexe während der MOCVD zu ana-lysieren. Thermogravimetrische Untersuchungen bzw. MOCVD-Versuche liessen Rück-schlüsse auf die Eignung der Komplexe des Typs [(PR3)MX] zur Abscheidung elementa-ren Kupfers zu. Des Weiteren wurde die Eignung von Ruthenium-Komplexen des Typs RuX2 (X = substituierte Cyclopentadienyle, 2,4-Dimethylpentadienyl, 4-Methylpent-3-en-2-on-yl) zur Erzeugung von elementaren bzw. oxidierten Rutheniums während MOCVD-Versuchen untersucht. Vorhergehende thermische Untersuchungen an den synthetisierten Komplexen liessen erste Rückschlüsse auf deren Eigenschaften zu. Da der Dampfdruck der für CVD-Zwecke eingesetzten Precursoren besonders interessant ist, wurden diese für die verwendeten Ruthenium-Komplexe bestimmt und sowohl untereinander als auch mit Lite-raturwerten verglichen. Ausgewählte Ruthenium-Komplexe wurden zur Erzeugung metal-lischer oder oxidischer Schichten während MOCVD-Versuchen eingesetzt.

No description available.