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A catálise é a chave para o desenvolvimento de processos químicos sustentáveis e, portanto, o preparo de catalisadores que sejam mais ativos e seletivos é sempre uma questão atual. Utilizando as propriedades diferenciadas de nanopartículas metálicas e as vantagens de separação e estabilidade de um catalisador heterogêneo, este trabalho descreve novos catalisadores de níquel e de níquel-paládio em escala nanométrica, suportados em sólidos magnéticos, para hidrogenação de olefinas. Os catalisadores de níquel apresentados neste trabalho foram preparados pela metodologia de decomposição do precursor organometálico Ni(COD)2 (COD = ciclo-octadieno), que apresenta o metal em estado de oxidação zero e permite a formação de nanopartículas metálicas após a hidrogenação das ligações C=C do ligante. O catalisador de níquel aprimorado, composto por nanoagregados de níquel, apresentou atividade superior a qualquer outro reportado na literatura para o mesmo tipo de reação. Além disso, mesmo com a facilidade de oxidação do Ni(0), este novo catalisador teve apenas sua superfície oxidada a NiO ao ser armazenado em ar. O NiO formado foi facilmente reduzido por hidrogênio a Ni(0) em condições brandas (75°C) se comparado ao NiO bulk (270-520°C). Os catalisadores bimetálicos de níquel-paládio foram sintetizados por uma reação de substituição galvânica com Pd(OAc)2 em um catalisador de Ni(0) suportado e por decomposição simultânea dos precursores organometálicos Ni(COD)2 e Pd2(dba)3 (dba = dibenzilideno acetona) em diferentes frações molares. Os catalisadores bimetálicos preparados por substituição galvânica não resultaram em estruturas core(Ni)-shell(Pd) como o esperado, mas sim em nanopartículas de paládio depositadas sobre os nanoagregados de níquel. Os catalisadores preparados por decomposição simultânea dos complexos organometálicos, seja pela decomposição direta dos precursores sobre o suporte magnético ou pela impregnação de nanopartículas coloidais previamente formadas, resultaram tanto em nanoligas quanto em nanopartículas com segregação de níquel na superfície de acordo com as proporções empregadas dos dois metais. Todos os métodos explorados possibilitaram a obtenção de catalisadores bimetálicos ativos na hidrogenação do cicloexeno, sendo que o catalisador composto por 1,3% em massa de Ni e 0,017% em massa de Pd, obtido por uma reação de substituição galvânica, foi o catalisador que atingiu a maior atividade na reação de hidrogenação do cicloexeno. O uso de precursores organometálicos para a síntese de nanopartículas suportadas de níquel e níquel-paládio se mostrou um método eficiente para a obtenção de catalisadores com atividade diferenciada. A separação magnética, método empregado para a separação e recuperação dos catalisadores de níquel, permitiu o fácil manuseio e evitou a exposição ao ar e oxidação dos catalisadores, prolongando sua vida útil. / Catalysis is the key for the development of sustainable chemical processes, and consequently, the preparation of active and selective catalysts is always a current issue. Using the unique properties of metal nanoparticles and the advantages of separation and stability of heterogeneous catalysts, this Thesis describes new nanometric nickel and nickel-palladium catalysts, supported on magnetic solids, for hydrogenation of olefins. The nickel catalysts described in this Thesis were synthesized by the decomposition of the organometallic precursor Ni(COD)2 (COD = 1,5-cyclooctadiene), which contains zerovalent nickel, and allows the formation of metal nanoparticles after the hydrogenation of the C=C bonds of the ligand. The optimized nickel catalyst, composed by nickel nanoaggregates, showed superior activity when compared to any other catalyst reported in the literature for the same kind of reaction. Even with the propensity of oxidation of Ni(0), this new catalyst had only the surface oxidized when exposed to air. The fine NiO shell formed was easily reduced to Ni(0) with hydrogen under mild conditions (75°C) when compared to NiO bulk (270-520 °C). The bimetallic nickel-palladium catalysts were synthesized by the galvanic replacement reaction of Pd(OAc)2 and a supported Ni(0) catalyst and by the simultaneous decomposition of the organometallic precursors Ni(COD)2 and Pd2(dba)3 (dba = dibenzylidene acetone) in different molar ratios. The bimetallic catalysts obtained by the galvanic replacement reaction were not formed by core(Ni)-shell(Pd) structures as expected, but they were formed by palladium nanoparticles deposited over the nickel nanoaggregates. The catalysts obtained by simultaneous decomposition of the organometallic complexes, either by the decomposition of the precursors directly over the support or by the impregnation of pre-synthesized nanoparticles, resulted in both nanoalloys and nanoparticles with nickel segregation on the surface, depending of the ratio between the two metals. All methods of preparation of the bimetallic catalysts explored in this study allowed the formation of very active catalysts. On top of that is the catalyst with 1,3 wt% of Ni and 0,017 wt% of Pd, obtained by the galvanic replacement reaction, which achieved the highest activity in the hydrogenation of cyclohexene. The organometallic approach for the synthesis of supported nickel and nickel-palladium nanoparticles is an efficient method to obtain catalysts with outstanding activities. The magnetic separation method employed for separation and recovery of the catalysts containing nickel allows the easy handling and prevents exposure to air and undesirable oxidation of catalysts, extending their lifetimes.

Ph.D. / This thesis deals with the synthesis of nitrogen-donor compounds and their reaction with metal ions. The first type of nitrogen-donor compounds are the unconjugated diimines (N,N´-bis(diphenylmethylene)ethylenediamine (L1) and (N,N´-bis(diphenylmethylene)propylenediamine (L2). Compounds L1 and L2 were reacted with [NiBr2(DME)] or [NiCl2·6H2O] to form complexes (2.1a), (2.2a), (2.3a) and (2.4a). These nickel complexes were characterized by IR spectroscopy, elemental analysis and mass spectrometry. When the complexes were left in chloroform for prolonged periods, hydrolysis of the diimine ligand took place, leading to the formation of nickel complexes 2.1b, 2.2b, 2.3b and 2.4b. The identity of the hydrolysed nickel complexes 2.1b and 2.2b was confirmed by single crystal X-ray crystallography. Complex 2.1b crystallised in the P21/n space group, whilst 2.2b crystallised in the P-1 space group. Compounds L1 and L2 were also reacted with [PdClMe(MeCN)2] to form the palladium complexes (3.1) and (3.2). The palladium complexes were characterized by NMR spectroscopy, elemental analysis and single crystal X-ray crystallography. Attempts to recrystallize 3.1 from a dichloromethane solution led to the formation of 3.1a. Both complexes 3.1a and 3.2 crystallised in the P21/n space group. Complexes 3.1 and 3.2 were tested as catalysts for the Heck coupling reaction of iodobenzene with methyl acrylate or butyl acrylate at 80 C. The products from the coupling reactions were characterized by GC and NMR spectroscopy. These complexes were found to be highly active with 100% conversions observed in some instances. The second type of ligands that were prepared are the benzoylpyrazolyl compounds, (3,5-dimethylpyrazol-1-yl)phenylmethanone (C1), (3,5-ditertiarybutylpyrazol-1-yl)phenylmethanone (C2), (3,5-dimethylpyrazol-1-yl)-o-toluoylmethanone (C3), (3,5-ditertiarybutylpyrazol-1-yl)-o-toluoylmethanone (C4), (2-chlorophenyl)-(3,5-dimethylpyrazol-1-yl)methanone (C5), (2-chlorophenyl)-(3,5-ditertiarybutylpyrazol-1-yl)methanone (C6), (2-flourophenyl)-(3,5-dimethylpyrazol-1-yl)methanone (C7), (2-flourophenyl)-(3,5-ditertiarybutylpyrazol-1-yl)methanone (C8). These compounds were fully characterized using NMR spectroscopy, IR spectroscopy and elemental analysis. Compounds C1, C3, C5 and C7 were reacted with [NiBr2(DME)] to form nickel complexes (4.31-4.34). These nickel complexes were found to be insoluble in all common organic solvents and hence were characterized only by IR spectroscopy and elemental analysis. Compounds C1-C8 were also reacted with [PdCl2(MeCN)2] to form palladium complexes (4.35-4.42). Complexes 4.35-4.42 were characterized using NMR spectroscopy, IR spectroscopy, elemental analysis and in selected cases single crystal X-ray crystallography. Complex 4.39 crystallised in the C2/n space group and complex 4.42 crystallised in the P21/n space group. Attempts to recrystallize 4.37a led to the formation of 4.37b, which contains both 3,5-dimethylpyrazol-1-yl)-o-toluoylmethanone and 3,5-dimethylpyrazole as ligands. Complex 4.37b was confirmed by NMR spectroscopy and single crystal X-ray crystallography. Complex 4.37b crystallised in the Pbca space group. The formation of 4.37b is attributed to hydrolysis of 3,5-dimethylpyrazol-1-yl)-o-toluoylmethanone ligand in 4.37a due to the presence of adventitious water in the solvent. The palladium complexes (4.35-4.42) were tested as catalysts for the Heck coupling reaction of iodobenzene with butyl acrylate and also for the Suzuki coupling reaction of iodobenzene with phenylboronic acid or 4-chlorophenylboronic acid. In these reactions, complexes 4.35-4.42 were found to be highly active at 120 C. The pyrazolyl nickel and palladium complexes were further tested as catalysts in ethylene oligomerization reactions using EtAlCl2 as the co-catalyst. The nickel complexes were found to be the most active reaching TONs of 10.8105 g mol-1 h-1. The palladium analogues only gave TONs of up to 3.9105 g mol-1 h-1. The oligomers were characterized by GC and NMR spectroscopy and were found to be in the C10-C16 range, with C16 the most abundant olefin.

Assurer la disponibilité d'un métal afin de croitre est un processus microbien vital,particulièrement critique lorsque la source devient rare comme à l'intérieur d'un hôte. Dans ces travaux, nous décrivons et étudions deux opérons prédits pour coder les différentes fonctions permettant la synthèse, l'export et la récupération d'un nouveau métallophorebactérien analogue à nicotianamine des plantes. Des études préliminaires ainsi que d'autresétudes indiquent que ces systèmes sont fonctionnels, qu'ils permettent l'import de nickel et decobalt et que les transporteurs prédits sont importants pour la virulence de S. aureus. Encombinant des approches de biochimie, de génétique et de métabolomique nous proposons lastructure de ce métallophore chez S. aureus et P. aeruginosa et proposons aussi leurs modesde biosynthèse. Ce modèle reste encore à valider par des approches complémentaires maispermettrait de décrire pour la première fois un métallophore spécifique du nickel et du cobaltet un mode de synthèse original faisant appel à une épimérase, une enzyme apparentée auxnicotianamine synthase et enfin à une protéine appartenant à la famille DUF2338. Laconnaissance et l'utilisation de ces systèmes permettent aussi d'envisager des systèmes debioremédiation ou bien de récupération du nickel et du cobalt. / Ensuring the availability of a given metal for growth is a vital microbial process,especially critical when the source becomes scarce like inside a host. In this work, wedescribe and study two operons predicted to encode the various functions for the synthesis,export and recovery of a new bacterial metallophore similar to plant's nicotianamine.Preliminary studies as well as studies in the literature indicate that these systems arefunctional, participate in the import of nickel and cobalt and that the predicted transporters areimportant for the virulence of S. aureus. By combining approaches from biochemistry,genetics and metabolomics we propose the structure of this metallophore in S. aureus and P.aeruginosa and also offer ways of their biosynthesis. This model remains to be validated butwould describe for the first time a specific metallophore for nickel and cobalt and an originalbiosynthetic route involving an epimerase, an enzyme related to nicotianamine synthase andfinally a protein belonging to the DUF2338 family. The knowledge of these systems alsooffers the possibility to exploit them in the bioremediation or recovery of nickel and cobalt.

L'objectif de cette thèse est l'obtention de nouvelles données expérimentales en milieu acide borique dans le cadre du développement de modèles décrivant le comportement des produits de corrosion dans le circuit primaire, et notamment sur le relâchement du nickel par des phénomènes de dissolution/précipitation. Le travail présenté dans ce mémoire s'est focalisé sur une des phases solides du nickel, l'oxyde de nickel (NiO), ainsi que sur le comportement en solution de sa forme ionique, Ni2+. La solubilité de l'oxyde de nickel a été mesurée à haute température à l'aide d'un réacteur à circulation ouverte spécialement conçu pour fonctionner à haute température et haute pression. Compte tenu des concentrations très faibles en Ni dans les conditions de nos essais (300°C, pH>7, matrice bore-lithium), une méthode d'analyse du nickel dissous à l'échelle de l'ultra-trace (ng.kg-1) en milieu bore-lithium a été développée par ICP-MS et a été validée statistiquement par la méthode du profil d'exactitude. La complexation du nickel par les (poly)borates a ensuite été étudiée. Une expérience a été conduite où les ions nickel sont progressivement formés par oxydation d'une électrode de nickel métallique dans une solution d'acide borique. Basé sur les résultats expérimentaux et sur la modélisation de la spéciation aqueuse du bore, l'évolution du pH a montré l'existence significative d'un complexe nickel-bore. Le complexe neutre NiB3O4(OH)3 a été mis en évidence pour de fortes concentrations en acide borique, lorsque les polyborates sont présents. Les constantes d'équilibres ont été calculées à 25, 50 et 70°C, ainsi que les données thermodynamiques associées. Enfin, les cinétiques de dissolution de l'oxyde de nickel ont été mesurées en milieu acide chlorhydrique et en milieu acide borique de 25 à 100°C et un pH de 6. Les résultats ont mis en évidence un effet inhibiteur de l'acide borique sur les vitesses de dissolution de NiO dont le phénomène est exacerbé par l'augmentation de la température et de la concentration en bore. La formation d'un complexe surfacique a été mise en avant pour expliquer cet effet. / This work focuses on the nickel oxide phase (NiO) and the behavior in solution of its ionic form Ni2+. The solubility of nickel oxide has been determined at high temperature and pressure by the use of a flow through cell reactor specially designed to perform measurements in the conditions of the primary circuit. Because the solubility of nickel is very low at 300°C and pH>7, a new method for the determination of ultra-traces nickel concentrations in lithium/boron medium by ICP-MS coupled with a desolvator system nebulizer has been developed and validated by the statistical approach of accuracy profiles. The complexation of nickel by the (poly)borates has been also studied. Based on the experimental results and aqueous speciation modeling, the evolution of pH showed the existence of significant nickel-boron complexation. A neutral complex NiB3O4(OH)3 was postulated at high boric acid concentrations when polyborates are present, and the equilibrium constants were determined at 25, 50 and 70°C. The associated thermodynamics data have also been determined. Dissolution rates of nickel oxide have been measured in hydrochloric acid and in boric acid media up to 100°C and pH 6. Results showed that boric acid inhibits the dissolution rates of NiO and this phenomenon is enhanced by the temperature and the concentration of boron. The formation of a surface complex was postulated to explain this effect.

L'Europe est confrontée à des défis climatiques et énergétiques et vise à accroître l'utilisation de la biomasse dans la production d'énergies renouvelables. De nombreuses difficultés technologiques persistent, par exemple, la gazéification de la biomasse produit un gaz de synthèse riche en goudrons et H2S qui peuvent conduire à une désactivation des catalyseurs dans les réacteurs en aval. Notre objectif a été de développer des catalyseurs stables qui peuvent réformer complètement ces hydrocarbures contenus dans le gaz de synthèse. Des nanoparticules de nickel encapsulées dans des monocristaux de silicalite-1 creusée formant une cavité unique ("single-hollow") ont été étudiées. L'encapsulation a pour but de limiter le frittage des particules et le cokage dans des conditions de reformage difficiles. Le frittage de ces particules au sein de chaque monocristal a cependant été observé. La synthèse d'une nouvelle structure creusée (c'est-à-dire un monocristal de zéolites avec de multiples cavités mésoporeuses, nommé "multi-hollow") a été développée. L'exclusion en taille de composés aromatiques larges par la membrane l'échantillon a été démontré. Ce matériau a également permis d'améliorer la dispersion initiale des nanoparticules métalliques. L'activité de l'échantillon a cependant été affectée par deux facteurs principaux associés aux étapes de préparation, c'està- dire la formation d'une couche de silice à la surface des particules et d'un empoisonnement au phosphore. Au cours du réformage d'un gaz de synthèse model riche en hydrocarbures, la membrane silicalite-1 n'a pu empêcher la désactivation due aux goudrons des particules de nickel encapsulées, car ceux-ci craquent aux températures typiques de reformage en composés aromatiques plus petits, susceptibles de se diffuser à travers la paroi de type MFI. La préparation de matériaux analogues à base de Rh n'a pas pu être réalisée. Des catalyseurs à base de Rh et de Ni supportés sur alumine ont ensuite été testés. Nous avons montré que le H2S induit une chute significative de l'activité en reformage et que les catalyseurs au Rh sont les moins influencés par le cokage et l'empoisonnement au S. L'activité en reformage du méthane était proportionnelle à la surface spécifique en Rh. Une température de réaction élevée (> 875 °C) a été jugée nécessaire pour limiter la désactivation par cokage / Europe is facing climate and energy challenges and aims at increasing the utilization of biomass in the production of renewable fuels. Many technological difficulties remain, for instance, biomass gasification produces a syngas rich in tars and H2S that can lead to catalyst poisoning in downstream reactors. Our goal was to develop stable catalysts that could fully reform producer gas. Nickel nanoparticles encapsulated inside hollow silicalite-1 single crystals were studied. The encapsulation was expected to limit particle sintering and coking under harsh reforming conditions. These particles could still sinter within each single crystal. The synthesis of a novel hollow structure ("multi-hollow", i.e. a single zeolite crystal with multiple mesoporous cavities) was developed. The size-exclusion of large aromatic compounds from the sample was demonstrated. This material also enabled improving the initial dispersion of metal nanoparticles. The sample activity was yet adversely affected by two main factors associated with the preparation steps, i.e. the formation of a silica over-layer and phosphorus-poisoning. During the reforming of a simulated producer gas, the silicalite-1 membrane could not prevent tar-related deactivation of embedded nickel particles, because those were cracked at typical reforming temperatures into smaller aromatic compounds, which could diffuse throughout the MFI-type layer. The preparation of Rh-based multi-hollow analogues could not be achieved. Alumina-supported Rh and Ni-based catalysts were then tested. H2S induced a large drop of the reforming activity and Rh catalysts were the least impacted by coking and S-poisoning. Methane reforming rate were proportional to the Rh metal surface area. The use of high reaction temperatures (>875°C) was shown to be necessary to limit deactivation by coking

Malgré ses avantages économiques et environnementaux, le procédé de reformage à sec du méthane sur des catalyseurs au nickel supporté se heurte encore à des problèmes de frittage de la phase active (un métal de transition) et de dépôt de carbone, ce qui entraîne une diminution de l'activité catalytique. Cette thèse porte sur l'étude de l'effet de confinement du nickel dans des catalyseurs à base de silice mésoporeuse pour la production de gaz de synthèse par reformage du méthane par le CO2. Dans cette étude, les échantillons ont été caractérisés par physisorption de N2, DRX, MET/MEB, RTP, et, en plus, par Raman, SPX, HTP/SM, ATG/SM pour les catalyseurs après test catalytique. Les résultats montrent qu'un support mésoporeux bien structuré ayant une grande surface spécifique et un grand volume poreux est important pour une meilleure dispersion et stabilisation de la phase active à l'intérieur de la porosité. La silice mésoporeuse de SBA-15 (préparée en grande quantité), composée de grains allongés, semble être appropriée pour atteindre cet objectif. Il est de plus démontré que la formation de petites particules bien confinées à l'intérieur des pores favorise la résistance au dépôt de carbone. Ceci peut être obtenu en imposant un traitement hydrothermal au support, en utilisant la méthode deux solvants pour le dépôt de Ni, en passant à une réduction directe des échantillons non calcinés, en ajoutant du Rh en faibles quantités ou en utilisant du Ce comme promoteur, à condition que le Ni et Ce soient en interaction. / Although economically and environmentally advantageous, the methane dry reforming process using supported nickel based catalysts still faces problems of active phase (a transition metal) sintering and of carbon deposition, which result in catalytic activity loss. This thesis is focused on the study of the confinement effect of nickel in mesoporous silica-based catalysts for syngas production by reforming of methane with CO2. In this study, the samples were characterized by N2 sorption, XRD, TEM/SEM, TPR, in addition to Raman, XPS, TPH/MS, TGA/MS for the spent catalysts. The results indicate that a well-structured mesoporous support with high surface area and large pore volume is important for better dispersion and stabilization of the active phase inside the porosity. The mesoporous SBA-15 silica support (prepared in large quantity), composed of elongated grains, appear to be suitable for the purpose. Moreover, it is demonstrated that the formation of small nickel particles well-confined inside the pores favors carbon resistance. This can be achieved by applying hydrothermal treatment to the support, using two solvents method for Ni deposition, using direct reduction of uncalcined samples, adding Rh in small quantities or promoting with Ce, provided that Ni and Ce are in interaction.

Cette thèse a été réalisée dans le cadre de la valorisation des composés organiques volatils (COVs) tels que le toluène. Cette étude vise à mettre au point des catalyseurs efficaces pour l'élimination du toluène par reformage à sec et vaporeformage du toluène. Les solides de type hydrotalcite ont été choisis en raison des propriétés intéressantes des oxydes obtenus par leur calcination. Les catalyseurs à base de Ni, Mg, et Al ont été préparés par voie hydrotalcite. Afin d'améliorer l'activité catalytique, les éléments Ce et La ont été incorporés dans les solides pour substituer une partie de l'élément Al et les effets ont été étudiés. Dans un premier temps, les différents oxydes mixtes ont été caractérisés par différentes techniques physico-chimiques dont la Diffraction des Rayons X (DRX), les Analyses Thermiques (ATD, ATG), la Réduction en Température Programmée (RTP),... Dans un deuxième temps, les différents oxydes mixtes ainsi préparés ont été testés dans les réactions de reformage à sec du toluène. La substitution progressive des ions Mg²⁺ par les ions Ni²⁺ améliore l'activité des catalyseurs. Le cérium ou le lanthane interviennent au niveau du mécanisme réactionnel pour améliorer la sélectivité tout en réduisant le dépôt de carbone. Les performances catalytiques des oxydes sont ensuite testées vis-à-vis de la réaction de vaporeformage du toluène montrant que la réactivité s'améliore avec l'augmentation de la teneur en magnésium. Les promoteurs ont montré un effet sur la conversion et la sélectivité en hydrogène. Selon les caractérisations physico-chimique après test catalytique, les catalyseurs n'ont montré aucune formation de coke. Une comparaison entre le meilleur catalyseur de cette étude et un catalyseur industriel est abordée. / This thesis was carried out in the context of the valorization of volatile organic compounds (VOCs) such as toluene. This study aimed to optimize efficient catalysts for the elimination of toluene by dry and steam reforming of toluene. Hydrotalcite solids were chosen because of the interesting properties of the oxides obtained by their calcination. The Ni, Mg and Al-based catalysts were prepared via hydrotalcite road. In order to improve the catalytic activity, the elements Ce and La were incorporated into the solids to substitute a part of the element A1 and the effects were studied. Initially, the mixed oxides were characterized by different physico-chemical techniques including X-Ray Diffraction, Thermal Analysis (TG/DTA), Temperature Programmed Reduction (TPR),... In a second step, the mixed oxides were tested in the dry reforming of toluene reaction. The progressive substitution of Mg²⁺ ions by Ni²⁺ ions improves the activity of the catalysts. Cerium or lanthanum played a role in the reaction mechanism, to improve selectivity and reduce carbon deposition. The catalytic performances of the oxydes are tested in the steam reforming of toluene reaction, showing that the reactivity improves with the increase in the magnesium content. The promoters have enhanced the toluene conversion and hydrogen selectivity. According to the physico-chemical characterizations after the catalytic test, the catalysts showed no coke formation. A comparison between the best catalyst of this study and an industrial catalyst is performed.

M.Sc. (Chemistry) / This study deals with the synthesis of nitrogen-donor pyrazole- and pyrazolylethylamine compounds, their reactions with palladium(II) and nickel(II) precursors to form complexes and the applications of theses palladium(II) and nickel(II) complexes as catalysts for ethylene oligomerization reactions and reactions of higher α-olefins in Friedel-Crafts alkylation of aromatic solvents. A series of ligands, 3,5-di-tert-butyl-1H-pyrazole (L3), 3,5-diphenyl-1H-pyrazole (L4), 5-phenyl-3-(trifluoromethyl)-1H-pyrazole (L5) were synthesized using appropriate amounts of diketones and hydrazine hydrate; while ligands, 2-(1H-pyrazol-1-yl)ethylamine (L6), 2-(3,5-dimethyl-1H-pyrazol-1-yl)-ethylamine (L7), 2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)-ethylamine (L8), 2-(3,5-diphenyl-1H-pyrazol-1-yl)-ethylamine (L9) and 2-(5-phenyl-3-(trifluoromethyl)-1H-pyrazol-1-yl)ethylamine (L10) were prepared via the N sp3 alkylation of the corresponding pyrazoles with bromoethylamine Reactions of L1-L5 with [PdCl2(CNMe)2] formed five complexes of general formula [PdCl2 (L)2] {L = L1 (2.1), L2 (2.2), L3 (2.3), L4 (2.4) and L5 (2.5)}. Similarly [NiBr2(DME)] formed five complexes of general formula [NiBr2(L)2] {L = L1(2.6), L2 (2.7), L3 (2.8), L4 (2.9) and L5 (2.10)}. Complexes 2.1-2.10 were synthesized in a 2:1 mole ratio of ligand and metal precursor. Reactions of L6-L10 with [PdCl2(MeCN)2] yielded complexes 3.1-3.5 respectively. Ligands L6-L10 were also complexed with NiCl2.6H2O to give complex 3.6 while [NiCl2(DME)] and [NiBr2(DME)] gave complexes 3.7-3.8 and 3.9-3.13 respectively...

M.Sc. / In search of developing new pyrazolyl complexes that can be used for ethylene transformation reactions, bis(pyrazolyl)alky carbonyl and amine complexes were prepared. The reaction between 3,5-dimethylpyrazole with alkyl-carbonyl chloride linkers in the presence of triethylamine as a base produced the ligands, 1,3-bis(3,5- dimethylpyrazol-1-yl)-propan-1-one (L1), 1,2-bis(3,5-dimethylpyrazol-1-yl)-ethane- 1,2-dione (L2), 1,4-bis(3,5-dimethylpyrazol-1-yl)-butane-1,4-dione (L3) and 1,6- bis(3,5-dimethylpyrazol-1-yl)-hexane-1,6-dione (L4) as white to brown crystalline solids in good yields. Ligand L5 was prepared by using bis(2-chloroethyl)-amine hydrochloride and 3,5- dimethylpyrazolevia via a phase-transfer reaction, while L6 was obtained using the bis(2-chloroethyl)-amine hydrochloride and 3,5-diphenypyrazole in the presence of triethylamine as a base. They were isolated in moderate yields, while their ditertiarypyrazole derivative was not obtained at all. All the ligands were characterized by a combination of 1H and 13C{1H}-NMR spectroscopy, infrared spectroscopy, elemental analysis and mass spectrometry. Ligands L1 and L4 were further confirmed by X-ray crystallography. Ligands L1 and L6 were subsequently used to prepare their corresponding Pd, Ni and Cr complexes. L1 was reacted with [PdCl2(NCMe)2] to form a bidentate complex 1,3- bis-(3,5-dimethylpyrazol-1-yl)-propan-1-one palladium dichloride (1a) when the reaction was heated at 80 oC, while a tridentate complex 1,3-bis(3,5-dimethylpyrazol- 1-yl)-propan-1-one palladium chloride (1b) was obtained when the reaction was refluxed. 1,3-bis(3,5-dimethylpyrazol-1-yl)-propan-1-one nickel(II) bromide (2) was obtained when NiBr2 was reacted with L1 at room temperature while the reaction between L1 and [CrCl3(THF)3] gave 1,3-bis(3,5-dimethylpyrazol-1-yl)-propan-1-one chromium(III) chloride (3). Ligand L6 was reacted with the same metal salts to give bis[2-(3,5-dimethylpyrazol- 1-yl)-ethyl] amine palladium(II) chloride (4), bis[2-(3,5-dimethylpyrazol-1-yl)-ethyl] amine nickel(II) chloride (5) and bis[2-(3,5-dimethylpyrazol-1-yl)-ethyl] amine chromium(III) chloride (6). All the complexes were characterized by the already mentioned characterization techniques and X-ray analysis was performed for 1b and 4. Ethylene transformation reactions were performed with complexes 1a, 2, 3, 5 and 6, and complexes 1a and 4 were not used because of their geometrical structures, which prevented them to be active for such reactions. Using MMAO and EtAlCl2 as cocatalysts complexes 1a and 3 showed no activity, however complexes 2 and 6 were active. Complex 2 was used with MMAO and showed no activity, while with EtAlCl2 oligomers were produced. Gas-chromatography analysis of the products showed that C6-C14+ oligomers were obtained. Temperature variation reactions performed under standard conditions of 20 bar ethylene pressure and 200 equivalents of EtAlCl2 in one hour showed that certain oligomers were not favoured under certain temperatures. Ethylene reactions with complex 6 and EtAlCl2 did not form any product but with MMAO polymer material was obtained. Analysis of the polymer by differential scanning calometry proved that the product was high density polyethylene. Studies of temperature, co-catalyst and pressure variations were performed. As expected for temperature studies the catalyst decomposed at high temperatures (above 40 oC), while for co-catalyst studies 3000 equivalents of MMAO gave the lowest TON. Pressure variations studies showed that an increase in ethylene pressure also increased the TON, but above 30 bar the activity became stable.