La thèse se concentre sur la synthèse et la caractérisation de nouveaux complexes de manganèse comme alternative possible aux complexes de gadolinium, actuellement les agents de contraste de choix pour l’Imagerie par Résonance Magnétique (IRM). Dans cette perspective, nous nous sommes intéressés à trois groupes de ligands pentadentés pour la complexation de Mn2+. Des nombres de coordination de 6 ou 7 ont été déterminés par cristallographie pour ces complexes, permettant la coordination d’une ou deux molécules d’eau en première sphère de coordination de Mn2+. La stabilité thermodynamique de ces complexes est plus faible que celle de complexes polyaminocarboxylates et leur dissociation est très rapide comparée à [Mn(nota)] et [Mn(dota)]2-. Seuls les complexes de Mn2+ avec des ligands macrocycliques à 12 atomes sont oxydés en Mn3+ à l’air. Les relaxivités des complexes bishydratés sont deux fois plus élevées que celles des complexes monohydratés et elles sont comparables à celles des agents de contraste commerciaux. Les données de RMN d’17O mesurées à différentes températures ont montré que l’échange d’eau peut être lent, intermédiaire, ou rapide selon le ligand. Les mesures à hautes pressions ont confirmé que le mécanisme d’échange est de type dissociatif pour les complexes avec un nombre de coordination de 7 et de type associatif pour les complexes avec un nombre de coordination de 6. Les petits anions bidentés endogènes peuvent remplacer une molécule d’eau dans les complexes bishydratés de macrocycles pentaazotés à 15 atomes, alors que pour les autres soit le complexe se décompose, soit il n’y a pas d’influence. / The thesis is focused on the synthesis and characterization of novel manganese complexes as alternative to Gd3+ chelates which are wide-spread contrast agents in Magnetic Resonance Imaging (MRI). In this perspective, three structurally different groups of pentadentate ligands for Mn2+ complexation have been investigated. Coordination numbers of 6 or 7 were determined in the crystal structure of the Mn2+ complexes enabling one or two water molecules in the first sphere. The thermodynamic stability of the chelates is lower than that of polyaminocarboxylate complexes and their dissociation is very fast in comparison to [Mn(nota)] and [Mn(dota)]2–. Only Mn2+ complexes with 12- membered ligands undergo oxidation in air to Mn3+ species. The proton relaxivities of the bishydrated complexes are two times higher than those for monohydrated complexes and are comparable to those of commercial contrast agents. Variable-temperature 17O NMR data revealed that the water exchange varies from slow to intermediate or to extremely fast, depending on the ligand. High-pressure 17O NMR measurements confirmed dissociative water exchange mechanism on complexes with CN = 7 and associative mechanism on complexes with CN = 6. Small endogenous bidentate anions are capable of replacing only one water molecule in the bishydrated complex with the 15-membered pentaaza ligand (L2), while in other cases the complex is decomposed or no influence is observed.

L'objectif de cette thèse est la synthèse d'un matériau modèle de la dioxygénase à manganèse, une enzyme oxydant des cycles aromatiques type catéchol grâce au dioxygène. Pour ce faire, nous avons découpé notre stratégie trois étapes constituant les différents chapitres de ce manuscrit : - La synthèse et la caractérisation des complexes de manganèse(II) avec des ligands tridentates. - L'optimisation d'une synthèse de silice mésoporeuse par micro-onde. - La fonctionnalisation des matériaux et le greffage des complexes, ainsi que les tests catalytiques préliminaires.Les ligands utilisés sont des amines tertiaires avec un bras alcyne et deux coordinants type pyridine, imidazole ou carboxylate. Ces complexes ont été cristallisés et/ou caractérisés par IR, RPE, SQUID et voltampérométrie cyclique. La synthèse par micro-onde, basée sur des conditions de synthèse hydrothermale classiquenous a permis de réduire le temps de synthèse d'un jour à deux heures. La qualité de ces nouveaux matériaux a été vérifiée par IR, ATG, BET, et DRX sur poudre. Ces matériaux sont ensuite bifonctionnalisés en utilisant une méthode de pochoir moléculaire avec une fonction azoture pour le greffage du complexe via "click-chemistry" ainsi qu'une fonction pyridine ou triméthylsilyle pour créer un environnement coordinant ou non proche du métal.Ces complexes et matériaux sont actifs dans l'oxydation du catéchol. / The objective of this work is the synthesis of model material for manganese dioxygenase which is an enzyme that oxidizes catechol-like substrates with dioxygen. Our strategy comprises three main steps that form the different chapters of this thesis: - Synthesis and characterization of manganese(II) complexes with tridentate ligands. - Optimization of a microwave-assisted synthesis of a mesoporous silica. - Functionalization of these materials and complex grafting, as well as preliminary catalytic tests. The ligands used are tertiary amines containing an alkyne arm and two coordinating arms with functions such as pyridine, imidazole or carboxylate. The complexes were crystallized and/or characterized by IR, EPR, SQUID and cyclic voltamperometry. Microwave synthesis, based on the conditions of classical hydrothermal synthesis, allowed us to reduce the synthesis time from one day to two hours. The quality of these new materials was verified by IR, TGA, BET and powder XRD. These materials are then bi-functionalized using a molecular stencil patterning mehod with a an azide function for complex grafting via click chemistry and a function pyridine or trimethylsilyl to control the coordinating ability of the metal environment. These complexes and materials are active in catechol oxidation with O2.

The objective of this work is the synthesis of model material for manganese dioxygenase which is an enzyme that oxidizes catechol-like substrates with dioxygen. Our strategy comprises three main steps that form the different chapters of this thesis: - Synthesis and characterization of manganese(II) complexes with tridentate ligands. - Optimization of a microwave-assisted synthesis of a mesoporous silica. - Functionalization of these materials and complex grafting, as well as preliminary catalytic tests. The ligands used are tertiary amines containing an alkyne arm and two coordinating arms with functions such as pyridine, imidazole or carboxylate. The complexes were crystallized and/or characterized by IR, EPR, SQUID and cyclic voltamperometry. Microwave synthesis, based on the conditions of classical hydrothermal synthesis, allowed us to reduce the synthesis time from one day to two hours. The quality of these new materials was verified by IR, TGA, BET and powder XRD. These materials are then bi-functionalized using a molecular stencil patterning mehod with a an azide function for complex grafting via click chemistry and a function pyridine or trimethylsilyl to control the coordinating ability of the metal environment. These complexes and materials are active in catechol oxidation with O2.

[pt] Neste trabalho estudou-se a remoção de manganês II, de efluentes da indústria mineira, por sorção, utilizando dois tipos de sorventes: o minério de paligorsquita proveniente Nova Guadalupe (Piauí) e a fração pesada das cinzas proveniente da queima de carvão mineral da indústria termoelétrica de Tubarão (SC). Foi apresentado um breve histórico da sorção de metais em argilas e óxidos, além das características dos processos de sorção e a análise dos principais trabalhos correlatos disponíveis na literatura, procurando evidenciar dados de isotermas e cinética de sorção em sorventes similares. Para a caracterização dos sorventes realizaram-se: análise granulométrica, fluorescência e difração de raios-X, análise termogravimétrica, medição da superfície especifica (BET) e análise com o microscópio eletrônico de varredura. Para avaliar o efeito múltiplo das variáveis: concentração inicial de manganês, pH, força iônica e razão sorvente/solução, na sorção de manganês utilizou-se a metodologia de supe rfície re sposta, empregando o planejamento estatístico central composto para ambos os sorventes. As variáveis mais significativas foram a razão sorvente/solução, a concentração inicial de manganês e a força iônica, para a paligorsquita; e para as cinzas de carvão foram a concentração inicial de manganês, a razão sorvente/solução e o pH. Determinou-se a cinética de sorção de manganês a diferentes valores de pH a 25 ºC, adequandose melhor o modelo de pseudo -segunda ordem para os dois tipos de sorvente. Mostrou-se uma maior constante cinética a pH 8,5 (26,6 g.mg -1min -1) para a paligorsquita e para as cinzas de carvão a pH 6,0 (5,02 g.mg -1min-1). Foram testados os modelos de Langmuir e Freundlich para avaliar a capacidade de sorção dos sorventes. O modelo de Fr eundlich se ajustou melhor para a paligorsquita e o modelo de Langamuir para as cinzas de carvão. A importância dos resultados obtidos visa à utilização destes sorventes na remoção de manganês de acordo com as características do efluente e da disponibilidade do sorvente, além de abrir a possibilidade de aplicação destes sorventes para remoção de outros metais. / [en] In this work the removal of manganese II, of mining industry effluent was studied, by sorption, using two types of sorbent s: palygorskite ore and heavy coal ash (proceeding from coal burning of a thermo electrical plant ). A brief historical of metals sorption in clays and oxides was presented, besides the characteristics of sorption processes and the analysis of the main works available in literature, looking for evidence isotherms and sorption kinetic data in similar sorbent s. The sorbents characterization was realized by: screen anal ysis, X-ray fluorescence and diffraction, thermo gravimetric analysis, specific surface area (BET) and scanning electron microscopy. To evaluate the multiple effect of the variable s: manganese initial concentration, pH, ionic strength and ratio sor bent/sol ution, in the manganese sorption was used the surface res ponse methodology, us ing a statistical experimental central composite design for both sor bents. The most significant variables were the ratio sorbent/solution, the initial manganese concentration and the ionic strength, for the pal ygorskite; and for coal ash were the initial manganese concentration, the ratio sorbent/solution and the pH. It was determined the manganese sorption kinetic at different pH values at 25ºC.The pseudo-second order model found to be the best correlation for both types of sorbents. The greater kinetic constant was obtained in pH 8.5 (26.6 g.mg-1min-1) for the palygorskite and for coal ash in pH 6,0 (5. 02 g.mg-1min-1). Langmuir and Freundlich models had been tested to evaluate the sorption capacity of the sorbents. The experimental data were correlated better by the Freundlich isotherm model for the palygorskite and the Langmuir isotherm model for coal ash. The importance of the results aim to use these sorbents in the manganese removal in agreement with the characteristics of the effluent and the availability of sor bent s, besides, opening the possibility to use these sor bents for the removal of other metals.

La chimie de coordination de l’ion manganèse(II), à partir de radicaux nitronyl nitroxyde et de macrocycles thiacalix[4]arènes, a mis en évidence des propriétés magnétiques et optiques remarquables au sein de ses complexes. Ces matériaux moléculaires ont la particularité de manifester leurs propriétés sous l’application de stimuli externes. Ainsi, un composé lamellaire à base de polymères de coordination bidimensionnels d’ions Mn(II) et de radicaux nitronyl nitroxyde, a révélé une conversion de tautomérisme de valence induite thermiquement, et des complexes polynucléaires d’ions Mn(II)−sulfonylcalix[4]arènes ont montré une luminescence intense centrée sur l’ion métallique sous éclairement. Nos travaux de thèse s’insèrent dans la continuité de ces résultats développés antérieurement dans notre équipe. Notre objectif a été de comprendre l’origine des perturbations électroniques subies par l’ion Mn(II) dans ces complexes de coordination. Pour cela, l’étude approfondie des relations entre les structures cristallines des composés Mn(II)−radicaux et Mn(II)−thiacalix[4]arènes et leurs propriétés physiques, a été au cœur de notre recherche. Ce manuscrit présente les synthèses, les structures cristallines et la caractérisation des propriétés magnétiques et optiques de composés obtenus par des processus d’ingénierie moléculaire. La modification des ligands nitronyl nitroxyde et thiacalix[4]arènes par synthèse organique, et la substitution des contre-ions au sein de ces complexes ioniques lors de leur synthèse, ont été le fil conducteur de nos travaux. Ces modifications chimiques ont permis d’élaborer de nouveaux complexes qui présentent à leur tour une conversion de tautomérisme de valence thermo-induite ou une forte luminescence centrée sur l’ion Mn(II). La comparaison des structures et des propriétés des nouveaux complexes obtenus et antérieurs, a permis une interprétation et une rationalisation des relations structures-propriétés. Ces résultats permettront par la suite d’améliorer et de moduler, de façon maitrisée et selon la nécessité, les structures moléculaires et à l’état solide des composés suivant les propriétés visées / Manganese(II) coordination chemistry, with nitronyl nitroxide radicals and thiacalix[4]arene macrocycles, revealed remarkable magnetic and optical properties. These molecular compounds show their properties under external stimuli. Recently, a lamellar compound, made of Mn(II) – nitronyl nitroxyde 2D coordination polymers, presented a thermo-induced valence tautomeric conversion, and Mn(II) – thiacalix[4]arene polynuclear complexes shown an intense luminescence centered on the metallic ion. Our PhD work takes part in the continuity of these previous results. Our goal was to understand the origin of the electronic perturbations inside these compounds. The depth study of the relationships between the structures and the physical properties was the central point of our research. This thesis will present the synthesis, the crystalline structures and the magnetic and optical characterizations of new compounds obtained by different molecular engineering processes. Organic modifications of the ligands and substitution of the counter-ion during the synthesis were the central thread of our work. Thanks to these chemical modifications, new compounds has been synthesized which are presenting also a thermo-induced valence tautomeric conversion or an intense luminescence. The comparison of all compounds made possible an interpretation and a rationalization of the structure-property relationships. Next step will be to improve or to modulate, in function of the need, the molecular or solid state structures regarding the expected properties

The thesis is focused on the synthesis and characterization of novel Mn2+ complexes as alternative to Gd3+ chelates which are wide-spread contrast agents in Magnetic Resonance Imaging (MRI). In the perspective to find suitable chelators of Mn2+ , three groups of pentadentate ligands with different size of macrocylic cavity, different donor atoms and number of pendant arms containing various functional groups have been investigated. Coordination numbers of 6 or 7 were found in the crystal structure of the Mn2+ complexes enabling binding of one or two water molecules in the first coordination sphere. The direct water coordination causes a decrease in the complex stability and thus, the thermodynamic stability of investigated chelates is lower than that of polyaminocarboxylate complexes and their dissociation is very fast in comparison to [Mn(nota)] and [Mn(dota)]2- . The studied Mn2+ complexes do not undergo oxidation in air except for complexes with 12-membered ligands which are oxidized to Mn3+ species. The proton relaxivities of the bishydrated complexes are two times higher than those for monohydrated complexes and are comparable to those of commercial contrast agents based on Gd3+ complexes. Variable-temperature 17 O NMR data revealed that the water exchange varies from slow to intermediate or...