Catalysis is one of the pillars of the chemical industry. While the use of catalyst is typically recognized in the automobile industry, their impact is more widespread as; catalysts are used in the synthesis of 80% of the US commercial chemicals. Despite the improved selectivity provided by catalyst, process inefficiencies still threaten the sustainability of a number of synthesis methods, especially in the pharmaceutical industry. Recyclable solid supported catalysts offer a unique opportunity to address these inefficiencies. Such systems coupled with continuous synthesis techniques, have the potential to significantly reduce the waste to desired product ratio (E-factor) of the production techniques. This research focuses developing sustainable processes to synthesize organic molecules by using continuous synthesis methods. In doing so, solid supported metal catalyst systems were identified, developed, and implemented to assist in the formation of carbon-carbon bonds. Newly developed systems, which utilized metal nanoparticles, showed reactivity and recyclability, comparable to commercially available catalyst. Nanoparticles are emerging as useful materials in a wide variety of applications including catalysis. These applications include pharmaceutical processes by which complex and useful organic molecules can be prepared. As such, an effective and scalable synthesis method is required for the preparation of nanoparticle catalysts with significant control of the particle size, uniform dispersion, and even distribution of nanoparticles when deposited on the surface of a solid support. This project describes the production of palladium nanoparticles on a variety of solid supports and the evaluation of these nanoparticles for cross coupling reactions. This report highlights novel synthesis techniques used in the formation of palladium nanoparticles using traditional batch reactions. The procedures developed for the batch formation of palladium nanoparticles on different solid supports, such as graphene and carbon nanotubes, are initially described. The major drawbacks of these methods are discussed, including limited scalability, variation of nanoparticle characteristics from batch to batch, and technical challenges associated with efficient heating of samples. Furthermore, the necessary conditions and critical parameters to convert the batch synthesis of solid supported palladium nanoparticles to a continuous flow process are presented. This strategy not only alleviates the challenges associated with the robust preparation of the material and the limitations of scalability, but also showcases a new continuous reactor capable of efficient and direct heating of the reaction mixture under microwave irradiation. This strategy was further used in the synthesis of zinc oxide nanoparticles. Particles synthesized using this strategy as well as traditional synthesis methods, were evaluated in the context industrially relevant applications.

Purpose: To evaluate the tensile strength properties of Rx Naturelle Plus and Option (high-palladium) alloys on soldered connectors under simulated preceramic and postceramic soldering conditions. Materials and methods: Eighty cylindrical castings were fabricated (40 using Rx Naturelle Plus alloy and 40 using Option alloy). The 40 castings for each alloy were subdivided into 2 groups of 20 each. In the first group, castings for each alloy were randomly paired and soldered with SMG2 solder to produce 10 preceramic test connector specimens for each alloy. In the second group, castings were similarly paired and soldered with 490 fine solder to produce 10 postceramic test connector specimens for each alloy. Each solder connector was subjected to tensile force until failure using an Instron testing machine. Statistical analysis using a Wilcoxon Rank Sums Test was performed.Results: No significant difference was found between the mean connector strength for Rx Naturelle Plus preceramic solder (mean tensile failure stress, 50,000 Psi; STD, 11,250) compared to Option preceramic solder (mean tensile failure stress, 59,700.4 Psi; STD, 16,350) (p= 0.1202). However, the connector strength for Rx Naturelle Plus postceramic solder (mean tensile failure stress, 37,800 Psi; STD, 32,450) was significantly lower than the Option postceramic solder (mean tensile failure stress, 45,300 Psi; STD, 17,550) (p= 0.0407). Not only did Rx Naturelle Plus postceramic solder connectors show evidence of lower strength, but also an increased variation among specimens.Conclusions: Rx Naturelle Plus solder connectors provided better strength with the preceramic are opposed with the postceramic connectors. For postsolder connectors, Rx Naturelle Plus alloy had less acceptable strength and a wider variation, suggesting it is more technique sensitive than Option alloy connectors.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Dans ce travail, l'oxydation totale du toluène et de la butanone sur des catalyseurs à base d'or et de palladium supportés sur un oxyde de titane macro-mésoporeux a été étudiée. Nous avons tout d'abord discuté l'effet bénéfique du dopage (V, Nb, Fe, Ce, Ni) du support TiO₂ macro-mésoporeux sur l'activité catalytique de ce matériau. Une interaction existant entre le dopant et le support a joué un rôle important dans l'augmentation de l'activité des matériaux dopés par rapport à celle du titane pure. Une phase active constituée d'or et/ou de palladium a été ensuite déposée sur les solides dopés et la performance des catalyseurs préparés a été suivie dans l'oxydation du toluène et de la butanone. La présence de la phase active a assuré une sélectivité totale pour le CO₂ avec la formation de sous-produits en particulier dans l'oxydation de la butanone. Par ailleurs, l'oxydation du mélange des deux COVs a montré l'existence d'une compétition entre les molécules en terme d'adsorption sur le support, ce qui a favorisé leur éliminationà de basses températures. Une étude operando DRIFT réalisée dans l'oxydation du mélange toluène/butanone a vérifié la présence de cette compétition. / In this work, the total oxidation of toluene and butanone over noble metal loaded doped titanium oxide supports has been investigated. The study focused firstly on showing the effect of doping a macro-mesoporous titania with metal oxide supports in the oxidation of VOCs. It seems that doping enhances the performance of the used solid in VOC oxidation reactions. We proved that this increase can be directly related to interactions between the dopants and the support. Then, an active phase made of noble metals has been loaded onto both best performing doped materials as to study the role played by this active phase in oxidation reactions. It appears that the presence of noble metals increases the catalytic performance of prepared materials and reduces the formation of toxic by-products such as CO. Butanone elimination proved to be harder that toluene oxidation, whereas when catalysts were exposed to a mixture of toluene and butanone, the presence of both VOCs prompted a competitive effect in the adsorption of both molecules onto the support, which facilitated their oxidation rate. An FTIR operando study illustrated the changes occuring in used catalysts in the oxidation of the VOC mixture, and verified the existence of this competitive effect.

This thesis has been focused on enzymatic kinetic resolutions and stereoselective oxidative transformations of enallenes catalyzed by PdII. In the first part of the thesis, a detailed discussion on Candida antarctica lipase B (CALB)-catalyzed kinetic resolution (KR) of δ-functionalized alkan-2-acetates is shown. We gained a deeper insight into the mechanism of enzyme-substrate recognition. Changing from an anhydrous solvent to water or a water-containing organic solvent enhanced the enantioselectivity. The effect of –OH was also confirmed by a lipase mutant suggesting that the water molecule mentioned above can be partly mimicked. In the second part of the thesis, we developed an efficient KR for allenic alcohols. On this basis, a novel synthesis of optically pure 2-substituted 2,3-dihydrofurans from allenic alcohols via a Ru-catalyzed cycloisomerization was reported. The developed protocol enabled us to assemble an optically pure precursor for total synthesis with three chiral centers from readily available allenol in 2 days. In the third part, we reported a class of reactions involving C–H cleavage under mild conditions: PdII-catalyzed oxidative transformations of enallenes. These reactions are particularly attractive since a number of meticulous structures have been achieved from readily accessible starting materials. The directing effect of an unsaturated hydrocarbon was found to be key for these transformations. In the final part, we developed the carbonylative insertion reaction discussed in the third part of the thesis into an asymmetric version. By using this methodology, a number of cyclopentenone compounds were obtained in good to excellent enantioselectivity.

Ph.D. / This work presents a detailed study of the synthesis of carbon nanotubes and nanospheres by nebulised spray pyrolysis. This method has been used by other workers mainly for preparation of sub-micron particles and the deposition of thin films on various substrates. The effect of various synthesis parameters including the temperature, choice of the carbon source and the metal precursor as well as the carrier gas flow rate on the selectivity of the reaction and the properties of the carbon nanotubes produced was investigated. A major part of this work was devoted to a study of the effects of the addition of small quantities of oxygencontaining compounds (alcohols, esters and aldehydes) to the reaction mixture. The products were analysed using various methods including TEM, SEM, Laser- Raman spectroscopy and HRTEM. Furthermore, the possible use of carbon nanotubes and carbon nanospheres as supports for palladium in the hydrogenation of ethylene was investigated. Nebulised spray pyrolysis proved to be a suitable technique for the synthesis of well graphitized carbon nanotubes and carbon nanospheres with uniform diameters and it was demonstrated that good control of the carbon nanotube properties could be achieved by controlling the synthesis parameters. Better graphitization of the carbon nanotubes was observed at higher temperatures. Ferrocene, iron pentacarbonyl, nickelocene and cobaltocene were successfully used in carbon nanotube synthesis with the last two producing carbon nanotubes with diameters close to those on single-walled carbon nanotubes. Toluene (with and without acetylene as a supplementary carbon source), benzene, mesitylene, xylene and nhexane were successfully used to produce carbon nanotubes with a high degree of alignment while no success was achieved with ethanol. The poor yields obtained with ethanol appear to be a consequence of chemical changes in the ethanol induced by exposure to ultrasound irradiation. On the other hand, low concentrations of methyl acetate and ethyl acetate appear to enhance the production of carbon nanotubes. It was demonstrated that carbon nanotubes and nanospheres are suitable for use as supports for palladium in the hydrogenation of ethylene. Pd particles of uniform size were obtained and the conversion rates were slightly higher when the carbon nanotubes were pre-treated with a mixture of sulphuric acid and nitric acid.

Indigo N,N’-diarylimine (Nindigo) and indigo N-arylimine (Mindigo) are redox-active ligands which exhibit near-infrared absorption and can accommodate up to five ligand charge states. This dissertation explores the coordination chemistry of these ligands to further understand the role that metal-ligand combinations play on ligand-centered properties, which include electrochemical potentials, UV-Vis-NIR absorption, pKa values, hydricities, and NH bond strengths at different ligand charge states. A series of cis-Nindigo palladium complexes containing acetylacetonate (acac) and hexafluoroacetylacetonate (hfac) ligands were synthesized. The acac complexes were easier to oxidize by 0.11 to 0.16 V and absorbed at lower wavelengths compared to their hfac analogues. Complexes using indigo bis(4-methylphenylimine) were more easily reduced than complexes of indigo bis(2,6-dimethylphenylimine). Cis- and trans-Mindigo complexes of palladium acac and hfac were synthesized as the first coordination complexes of Mindigo. Trans-Mindigo complexes were more difficult to reduce by 0.33 to 0.37 V and absorbed at lower wavelengths than their cis-Mindigo counterparts. Cis-Mindigo complexes were easier to reduce and harder to oxidize than the corresponding cis-Nindigo complexes. The NH bond strengths of cis-Nindigo complexes containing Pd(acac) and Ru(bipy)2 (bipy = 2,2’-bipyridyl) fragments were determined through a potential-pKa diagram in tetrahydrofuran and acetonitrile, respectively. The NH bond strength and hydricity values of the Pd(acac) complex were comparable to the values of diaryl amines. The NH bond strength and hydricity of the Ru(bipy)2 complex were substantially smaller due to the lower oxidation potentials of this complex. In both cases, the ligand’s NH bond strengths were not affected greatly by the ligand’s charge state. Ru(acac)2 complexes of neutral, aprotic cis-Nindigo and cis-Mindigo ligands were synthesized. The Nindigo/Mindigo ligand could be protonated, and the resulting complexes demonstrated substantial temperature dependence of some of their 1H NMR chemical shifts. The NH bond strengths and hydricities of the Ru(acac)2 complexes were determined using cyclic voltammetry and pKa measurements. The NH bond strengths and hydricities of these complexes are substantially smaller than the Pd(acac) and Ru(bipy)2 complexes. Collectively, these results show that Nindigo and Mindigo can act as both a proton and electron reservoirs, and the thermodynamics of proton and electron transfer can be tuned through the choice of metal and ligand combinations. / Graduate / 2020-07-17

Title: Light platinum group metal complexes with a ferrocene N-phosphinoamide Author: Bc. Michal Navrátil Department: Department of Inorganic chemistry Supervisor: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Abstract: The aim of this diploma thesis is the preparation of coordination compounds containing ferrocene phosphinoamide FcCONHPPh2 (1, Fc = ferrocenyl), whose preparation was discussed in author's bachelor thesis. Twelve new complexes are described in this thesis, including their characterisation by NMR and infrared spectroscopy, elemental analysis and mass spectrometry. In all cases the crystal structure was determined. Two palladium(II), one rhodium(III) and one ruthenium(II) precursors were used for the preparation of the complexes with each providing three new compounds. A reaction of the precursors with phosphinoamide 1 yielded complexes, in which the phosphinoamide was P-coordinated. This compound was a precursor for the other two complexes. The first one was obtained by a reaction with silver(I) perchlorate producing a cationic P,O-chelate. The other was obtained by a reaction with potassium tert-butoxide resulting in neutral P,O- chelate. All twelve complexes were prepared with optimised yields. Keywords: ferrocene, amides, phosphines, palladium, rhodium, ruthenium, structure elucidation.

Nesse estudo foi sintetizado e caracterizado o óxido de grafeno (OG) a partir do método de Hummers modificado. O OG foi utilizado como suporte para nanopartículas de paládio para uso como eletrocatalisador em células a combustíveis abastecidas diretamente a etanol. O uso de carbono grafite como suporte de nanopartículas metálicas é deteriorado com mais rapidez, levando a diminuição do tempo de vida útil da célula a combustível. O objetivo principal foi a incorporação do paládio no óxido de grafeno via feixe de elétrons, e a comparação com o catalisador incorporado por via química, utilizando o borohidrato de sódio. Foram utilizadas técnicas de caracterização tais como: termogravimetria (TG), difração de raios-X (DRX), as espectroscopias de Raman e infravermelho com transformada de Fourier (FT-IR), microscopia de transmissão eletrônica (MET), Espectroscopia de fotoelétrons por raios- X (XPS) e estudos voltamétricos como a voltametria cíclica e cronoamperometria. Os resultados indicaram que para a dose de 288 kGy, houve a incorporação, porém, não foi suficiente para que houvesse a redução dos grupos oxigenados, estudos com o oxido de grafeno previamente reduzido via térmica e incorporado via feixe de elétrons foram comparados na mesma dose. / In this study, graphene oxide (GO) was synthesized by the modified Hummers method and characterized. GO was used as support for palladium nanoparticles as an electrocatalyst on direct ethanol fuel cell (DEFC). One of the drawbacks using carbon graphite as a support for metal nanoparticles was because it deteriorates more quickly, leading to shortened fuel cell life. The main objective was the incorporation of Pd on the graphene oxide by the electron beam and was compared with the chemical incorporation, using sodium borohydride. Characterization techniques such as thermogravimetry (TG), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared (FT-IR), electron transmission microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and voltammetric studies such as cyclic voltammetry and chronoamperometry. The results indicated that at a dose of 288 kGy, there was an incorporation, however, it was not enough for there to be a decrease in the groups of oxygenates, studies with the graphene oxide downloaded through the thermal and through electron beams were compared in the same dose.

O estudo da eletrorredução de nitrato teve início na década de 70 e o catalisador mais estudado para esta reação é a platina, embora, para fins ambientais, o paládio seja mais indicado por apresentar maior seletividade para a formação de N2. Neste trabalho a eletrorredução de nitrato foi estudada em eletrodos de Pd, Pt e Pt com camadas de Pd. Primeiramente foi feito um estudo com nanopartículas de Pt, Pd e Pt com uma monocamada de Pd dispersas em carbono, mas a dificuldade em sugerir um mecanismo nesse tipo de eletrodo levou à utilização de eletrodos monocristalinos, que tem a superfície conhecida. Foram feitos estudos eletroquímicos em eletrodos de Pd(hkl) que não apresentaram grande atividade frente a redução de nitrato, uma vez que o potencial inferior não foi menor que 0,2 V, para evitar excessiva absorção de hidrogênio. Em Pt(hkl) os resultados obtidos estão de acordo com os publicados na literatura e comprovam a sugestão de que o produto final é NH4 +. Para observar a atividade do paládio frente à reação, foram utilizados eletrodos monocristalinos de Pt (hkl) com multicamadas de paládio, que se comportam como monocristais de paládio, mas sem absorver hidrogênio. Nestes materiais foram feitos estudos eletroquímicos e de FTIR. Verificou-se que a atividade dos eletrodos depende da estrutura e do eletrólito, mas a definição de um mecanismo fica comprometida pelo fato do solvente (H2O ou D2O) favorecer a formação de um produto ou outro, embora tenha sido comprovada a formação de NO(ads) em todos os casos. / The study of nitrate electro-reduction started in the 70s and the most studied catalyst for this reaction is platinum, however because of environmental reasons, palladium is more indicated since it has higher selectivity for the formation of N2. In this work the nitrate electro-reduction was studied on Pd, Pt and Pt modified with Pd layers. First, a study involving carbon-supported nanoparticles of Pt, Pd and Pt with a Pd single layer was carried out, but the difficulty suggesting a reaction mechanism for this kind of electrode has driven to the use of single crystals, because of their defined surface structure. So, electrochemical studies were made on Pd(hkl) electrodes, but these materials did not present great activity for nitrate reduction, because the electrode potential was not decreased below 0,2 V, to avoid large hydrogen absorption. For Pt(hkl) the obtained results are in agreement with those published previously, confirming the suggestion that NH4 + is the final product. To characterize the palladium activity for this reaction, Pt(hkl) single crystals with palladium multilayer were employed, because these materials have a behavior similar to palladium single crystals, but without hydrogen absorption. Electrochemical and FTIR experiments were done to characterize the i vs E responses and to follow the reaction intermediates and products. It was seen that the activity depends on the electrode structure and the electrolyte, but the mechanism determination pointed to a uncertain situation where the solvent (H2O or D2O) drives to the formation of one product or another, although the production of NO(ads) has been observed in all cases.