Les travaux présentés dans ce manuscrit de thèse concernent la mise au point de nouvelles méthodologies de synthèse asymétrique en organocatalyse promues par des phénolates d’ammoniums quaternaires, catalyseurs de type paires d’ions coopératifs chirales, et des dérivés de l’acide de Meldrum comme substrats. Dans un premier temps, nous avons utilisé l’acide de Meldrum comme un précurseur de cétène via une cycloréversion induite par O-silylation grâce à une probase silylée, afin de réaliser une réaction de cycloaddition [2+2] avec un aldéhyde ou une imine catalysée par un phénolate d’ammonium chiral, permettant de former des β-lactones et des β-lactames. Les travaux effectués n’ont cependant pas permis d’obtenir le produit désiré. Dans un secont temps, nous avons exploité le caractère électrophile des dérivés disubstitués de l’acide de Meldrum et leur capacité à fragmenter suite à l’addition nucléophile d’un phénolate. Une première partie a été consacrée au développement d’une réaction monotope de désymétrisation de l’acide de Meldrum pour former des malonates dissymétriques après une étape d’alkylation in situ du carboxylate intermédiaire. Bien que de bons rendements isolés aient été obtenus, un maximum de 21% ee a pu seulement être atteint. Dans une seconde partie, nous avons mis au point une séquence originale, catalysée par un phénolate d’ammonium quaternaire chiral, qui est constituée (1) d’une addition nucléophile de phénolate suivie (2) d’une fragmentation avec perte d’acétone qui permet, après (3) une étape de décarboxylation de générer un acétal de cétène acyclique qui va subir (4) une réaction de protonation énantiosélective. Cette méthode a pu être appliquée à un large panel de substrats avec de bons rendements et des excès énantiomériques allant jusqu’à 70% ee. / The work developed in this PhD thesis deals with the development of new asymmetric organocatalytic methodologies implying cooperative chiral ion pairing catalysis, by using chiral ammonium phenoxides as catalysts and Meldrum’s acid derivatives as substrates. First, we used the ability of Meldrum’s acid to generate acylketenes after cycloversion triggered by O-silylation thanks to a silylated probase in the presence of a chiral ammonium phenoxide. Such an approach was applied to the synthesis of β-lactones and β-lactames following a [2+2] cycloaddition reaction with aldehydes or imines respectively. Unfortunately, the desired products have never been observed. Then, we focused on disubstitued derivatives of Meldrum’s acids and their propensity to fragment after a nucleophilic addition of phenoxide. In a first part, we have developed a one-pot desymmetrization reaction of Meldrum’s acid derivatives to form dissymmetric malonates after an in-situ alkylation of the transient carboxylate. However, despite high isolated yields, only an unsatisfactory 21% ee could be reached. In a second part, we have developed an unprecedented sequence consisting of (1) a nucleophilic addition of phenol derivatives to Meldrum’s acid followed by (2) a fragmentation with loss of acetone, leading after (3) decaboxylation to the formation of an acyclic ketene acetal which is involved in (4) an enantioselective protonation reaction to provide a wide range of enantioenriched phenolic esters with moderate to excellent yield and up to 70% ee.

Le noyau est généralement décrit comme un ensemble de protons et de neutrons liés dans un potentiel de champ moyen. Cependant afin d'obtenir une meilleure description, il convient de tenir compte des interactions locales dont principalement l'appariement. Les appariements neutron-neutron et proton-proton sont assez bien étudiés alors que ce n'est pas le cas de l'appariement neutron-proton. Celui-ci peut être soit isovectoriel similaire à l'appariement nn/pp, soit isoscalaire et donc dans ce cas vraiment méconnu. La surliaison des noyaux N=Z pourrait être une manifestation de l'appariement np.Nous avons effectué l'étude de l'appariement np par réactions de transfert de paires np. Dans ce cas il est attendu que la section efficace de transfert de paires np soit augmentée en présence d'un appariement np important. L'appariement np devrait être important dans les noyaux N=Z avec des orbitales de J élevé. Or, des faisceaux de ces noyaux ne sont accessibles que depuis le développement des installations de faisceaux radioactifs.Nous avons effectué notre expérience au GANIL (Caen) avec un montage permettant une détection des produits issus de la réaction de transfert (p, ³ He). Cette réaction met en jeu à la fois des paires np isovectorielles et isoscalaires. Nous avons utilisé des faisceaux de ⁵⁶ Ni et de ⁵²Fe permettant d'observer l'évolution de l'appariement np avec l'occupation de la couche 0f7/2.Tout d'abord, nous avons analysé les données issues de la réaction ⁵⁶Ni(p,d)⁵⁵Ni et extrait des résultats que nous avons comparé à ceux existants. Cette démarche a permis de valider la procédure d'analyse des données.Après analyse des données issues de la réaction ⁵⁶Ni(p,3He)⁵⁴Co, nous avons extrait les populations des états du ⁵⁴Co qui donnent des informations sur l'intensité relative des deux types d'appariement np pour le noyau ⁵⁶Ni et montrent que l'appariement np isovectoriel est dominant dans ce noyau.De plus, dans le cadre d'un développement d'un futur détecteur de particules chargées, un travail de R&D sur la discrimination des particules légères par la forme des signaux a été réalisé et est présenté. / A nucleus is described as a set of independent neutrons and protons linked by a mean-field potential. However, in order to have a better description one needs to take in account some residual interactions such as pairing. Neutron-neutron and proton-proton pairings are well-studied but neutron-proton pairing is not well-known. np pairing can be isovector pairing such as nn and pp pairing or isoscalar which is yet unknown. Overbinding of N=Z nuclei could be a manifestation of np pairing.We have studied np pairing through transfer reactions. In this case, the cross-section of np pair transfer is expected to be enhanced in the presence of important np pairing. np pairing is expected to be important in N=Z nuclei with high J orbitals. Since the development of radioactive beam facilities, such beams are only available.The experiment was performed at GANIL with an efficient set-up so as to detect products from the (p,³He) transfer reaction. This reaction is affected by isovector and isoscalar np pairing. We used ⁵⁶Ni and ⁵²Fe beams so as to see the effect of the occupancy of 0f7/2 shell on the np pairing.First, we analysed the data from the ⁵⁶Ni(p,d)⁵⁵Ni reaction and we compared the results with the literature to validate analysis procedure.After analysing data from the ⁵⁶Ni(p,3He)⁵⁴Co reaction and extracting the population of the various states of ⁵⁴Co, we obtained information about the relative intensity between isoscalar and isovector np pairing in ⁵⁶Ni showing the predominance of isovector np pairing in this nucleus .Moreover, in the framework of developing a new charged particle detector, R&D on the discrimination of light nuclei using pulse shape analysis was performed and is presented.

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In design of bridges and for estimation of dynamic properties and load carrying capacity Finite Element Method (FEM) is often used as a tool. The physical quantities used in the Finite Element (FE) model are often connected to varying degrees of uncertainty. To deal with these uncertainties conservative parameter estimates and safety factors are used. By calibrating the bridge FE model to better fit with the response of the real structure, less conservative parameter values can be chosen. This method of comparing measured and response with estimates from a FE model and calibrating the model parameters is called Finite Element Model Updating (FEMU). In the present thesis different aspects of FEMU are investigated. The first part comprises a literature review covering all aspects of FEMU with special focus on the choice of updating parameters, objective functions for iterative updating procedures and the automatic pairing of modes. This part is concluded with a flowchart suggesting a systematic approach to a FEMU project. In the second part of the text two bridge case studies are presented. In the first case study a railway bridge in the north of Sweden is studied. A detailed FE bridge model from a previous project is used as a simulation model for extraction of modal data by eigenvalue analysis. Then simplified models are created and attempts to update these models are performed. The updating parameters are chosen based on a simple sensitivity analysis. Tests are performed to investigate the influence of chosen updating parameters and objective function on the computational cost and the quality of the updated model. Case study number two is more comprehensive and focuses on the sensitivity analysis for the choice of updating parameters and on the choice of objective function. A road bridge in the Stockholm area is used and as for case study one a detailed model from a previous project is used as simulation model. Also a new criteria for the automatic pairing of modes is presented and tested. In the end an attempt to verify two of the updated models is performed. / <p>QC 20150825</p>

Emergent electronic phenomena in iron-based superconductors have been at the forefront of condensed matter physics for more than a decade. Much has been learned about the origins and intertwined roles of ordered phases, including nematicity, magnetism, and superconductivity, in this fascinating class of materials. In recent years, focus has been centered on the peculiar and highly unusual properties of FeSe and its close cousins. This family of materials has attracted considerable attention due to the discovery of unexpected superconducting gap structures, a wide range of superconducting critical temperatures, and evidence for nontrivial band topology, including associated spin-helical surface states and vortex-induced Majorana bound states. Here, we review superconductivity in iron chalcogenide superconductors, including bulk FeSe, doped bulk FeSe, FeTe1−xSex, intercalated FeSe materials, and monolayer FeSe and FeTe1−xSex on SrTiO3. We focus on the superconducting properties, including a survey of the relevant experimental studies, and a discussion of the different proposed theoretical pairing scenarios. In the last part of the paper, we review the growing recent evidence for nontrivial topological effects in FeSe-related materials, focusing again on interesting implications for superconductivity.

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Mixed-metal supramolecular complexes containing one or two RuII light absorbing subunits coupled through polyazine bridging ligands to a RhIII reactive metal center were prepared for use as photocatalysts for the production of solar H2 fuel from H2O. The electrochemical, photophysical, and photochemical properties upon variation of the monodentate, labile ligands coordinated to the Rh reactive metal center were investigated. Bimetallic complexes [(Ph2phen)2Ru(dpp)RhX2(Ph2phen)]3+ (Ph2phen = 4,10-diphenyl-1,10-phenanthroline; dpp = 2,3-bis(2-pyridyl)pyrazine; X = Br- or Cl-) were prepared using a building block approach, allowing for selective component choice. The identity of the halide coordinated to Rh did not impact the light absorbing or excited state properties of the structural motif. However, the o-donating ability of the halides modulated the Rh-based cathodic electrochemistry and required the use of multiple pathways to explain the reduction of Rh by two electrons. Regardless of halide identity, the bimetallic complex possessed a Ru-based HOMO (highest occupied molecular orbital) and Rh-based LUMO (lowest unoccupied molecular orbital) important for photoinitiated electron collection at Rh. As a photocatalyst for H2 evolution, the X = Br- complex produced nearly 30% more H2 than the X = Cl- analogue. H2 production experiments with added halide suggested that ion pairing with halides played a major role in catalyst deactivation, which provided evidence for the importance of component selection for photocatalyst design. New trimetallic complex [{(bpy)2Ru(dpp)}2Ru(OH)2](PF6)5 (bpy = 2,2'-bipyridine) was prepared for comparison to halide analogues [{(bpy)2Ru(dpp)}2RhX2](PF6)5 (X = Br- or Cl-). The synthesis of a halide-free supramolecule containing OH- ligands afforded an ideal system to further examine the impact of the ligands at the reactive metal center on H2 photocatalysis. Electrochemistry results revealed that while the identity of the ligands at Rh did modulate the Rh-based reduction potential, all three complexes possessed a Ru-based HOMO and Rh-based LUMO. The light absorbing properties were not impacted by the identity of the monodentate ligands at Rh; however, the excited state properties did vary upon changing the ligands at Rh. The hydroxo trimetallic complex functioned as a photocatalyst for H2 production in organic solvent, producing nearly double the amount of H2 as the highest performing Br-' trimetallic complex in DMF solvent. Interestingly, H2 production studies in high dielectric aqueous solvent revealed no discrepancies in H2 evolution upon variation of the ligands at Rh, which further supported the ion pairing phenomenon realized for the bimetallic motif. Variation of the labile ligands coordinated to the Rh reactive metal center in RuIIRhIII multimetallic supramolecules provided important insight about the large impact of small structural variation on H2 photocatalysis. Electrochemical, photophysical, and photochemical studies of new RuIIRhIII complexes afforded a deeper understanding of the molecular processes important for the design of new complexes applicable to solar fuel production schemes. / Ph. D.

Pharmaceutical companies and FDA (Federal Drug Administration) rules rely heavily on crystalline active pharmaceutical ingredients delivered as tablets and powders in the form of neutral compounds, salts and solvates of neutral compounds and salts. About half of all drugs sold in the market are in the form of salts which are held together by ionic bonds along with some other forces. Recently, Ionic liquids (ILs) an interesting class of chemical compounds have offered potential opportunity for exploration as novel drug ionic liquid salts, particularly in the field of transdermal/topical drug delivery. Due to the multifunctional nature of these salts they could allow generation of new pathway to manipulate the transport and deposition behaviour of the drug molecule. It is this modular approach of IL that forms the basis of the research presented here, in which pharmaceutically acceptable compounds are combined with selected drugs with known problems. IL salts were generated by combining at least one drug molecule with FDA approved compounds and were assessed for physicochemical properties, skin deposition and permeation studies. Skin deposition data suggested that these systems exhibit high skin retention, which was found to correlate with the molecular weight. On the other hand, permeation data displayed an inverse relationship between flux values and molecular weight of the permeant. Similar work was extended with ILs with mixed anions containing two drugs. The benzalkonium-sulfacetamide ILs were investigated for synergism and the biological studies data display no synergistic effect. It was also illustrated that in-situ IL based ibuprofen hydrogels systems could be manipulated via IL approach for topical application. These findings suggest the potential applicability of IL based formulations for topical delivery of drugs.