WorldCat Identities

Martin-Vaca, Blanca (19..-....).

Overview
Works: 26 works in 35 publications in 2 languages and 36 library holdings
Roles: Thesis advisor, Other, Opponent, Contributor
Publication Timeline
.
Most widely held works by Blanca Martin-Vaca
Approche de systèmes géométriquement contraints à motif phosphazène by Christelle Freund( Book )

2 editions published in 2005 in French and held by 2 WorldCat member libraries worldwide

Cette thèse s'intéresse à des complexes monocyclopentadiényles à bras phosphazène des métaux du groupe 4. L'objectif était de générer des espèces capables de s'autoactiver grâce à une interaction entre le phosphazène et le métal, ou du moins de faciliter l'activation nécessaire, pour former une espèce cationique super acide de Lewis du type Catalyseur à Géométrie Contrainte. Une étude théorique des systèmes présentant l'arrangement “Cp-P=N” montre que cette interaction est favorisée dans le complexe neutre, et qu'elle stabilise le complexe cationique. Plusieurs ligands monocyclopentadiényles à bras phosphazène ont été synthétisés, selon deux modèles : “Cp-Si-N=P” et “Cp-P=N”. Ces systèmes offrent une structure particulièrement modulable. L'alcane élimination entre les ligands et le tétrabenzylzirconium a permis d'obtenir les complexes monocyclopentadiényle benzylzirconium à bras phosphazène correspondants. Ces complexes présentent des structures originales, par les modes de coordination des ligands (notamment une hapticité très rarement observée h1 pour le ligand fluorényle), et par les effets électroniques et stériques subtils qui favorisent ou non la coordination du bras phosphazène au centre métallique
Substituted Cyclopropylamines from Pyridinium Ylide: Complexes of Pentacarbonyl Tungsten and Enamines( )

1 edition published in 2000 in English and held by 2 WorldCat member libraries worldwide

Catalyse organique de polymérisation par ouverture de cycle : synthèse de polymères biodégradables à visée pharmacologique by Aurélie Alba( Book )

2 editions published in 2009 in French and held by 2 WorldCat member libraries worldwide

This work is in line with a collaboration between the galenical centre of Ipsen Pharma based in Barcelona (Spain) and the LHFA in Toulouse. New PLGA supports have been synthesized by organocatalysis at Toulouse and then formulated by Ipsen Pharma. In the first chapter, the synthesis of PLGA oligomers using an acidic catalyst is described, as well as multiple analytical techniques to determine the chemical and physico-chemical properties of the polymers. In order to better apprehend the results observed in formulation, some structure/activity relationship studies have been performed. The scale up of the polymerizations was also investigated, as well as the stability and tolerance of the polymers. In the second chapter, acidic or basic catalysts were used to synthesize hyperbranched macromolecular systems (star shape or dendrimer), still by ring opening of lactide and using multifunctional initiators (alcohols and/or amines). In the third chapter, a new bifunctional catalytic system consisting of a triflamide or sulfonamide, as hydrogen bond donor, and a tertiary amine, as hydrogen bond acceptor was screened and applied to the ROP of lactide. A bis-sulfonamide-DMAP couple is preferred for the preparation of well controlled PLA under mild conditions. Moreover, a range of mono-sulfonamide and bis-sulfonamide with different spacers were synthesized to undergo kinetic studies and determine the way of action of the catalyst. The two NH groups were shown to activate the monomer cooperatively, while the protic initiator is activated by the DMAP. In the fourth chapter, a new chiral derivatizing agent (CDA), named NaphtOCA, is synthesized and applied to the absolute configuration assignment of an a-chiral primary amine by 1H NMR spectroscopy. The NaphtOCA reacts immediately with an amine, without any coupling agent used, to generate an amide and an hydroxyl group. The way of action of this effective CDA was fully investigated
Activation de molécules par des complexes mono et multimétalliques ! : Une approche théorique by Yan Yang( Book )

2 editions published in 2021 in English and held by 2 WorldCat member libraries worldwide

During this thesis, we are interested in the theoretical study of the activation of small molecules such as CO2, H2, N2 by metal complexes involving s, d or f metals. This work has been done in close collaboration with experimental groups. The control of the reactivity of these small molecules remains an important challenge for the chemical industry but also from a societal point of view with for example the global warming. We have used theoretical calculation techniques of reaction mechanisms based on density functional theory to understand, explain and even predict the activity of metal complexes towards these small molecules. For example, we were able to show that the reduction of O2 by bimetallic iron(II) complexes could be achieved under mild experimental conditions by a monoelectronic transfer of each of the two metallic centers. This work was carried out in collaboration with the team of Professor LaPierre in Atlanta. In collaboration with Professor Piers' group at the University of Calgary, we were able to show that a simple modification of a ligand on iron or cobalt complexes could lead to either the easy activation of the oxygen molecule or the activation of the ammonia (NH3) molecule. These two results are significant because they show that the reactivity of transition metal complexes can be easily modulated to allow or not the activation of molecules as inert as O2 or NH3. We were also able to show in collaboration with the team of Professor Okuda from Aachen that a bimetallic complex of calcium hydride could react with the CO molecule and thus functionalize it. This work is a first approach of a Fischer-Tropsch type reaction starting from a molecular compound
Catalyse organique de polymérisation d'hétérocycles : préparation de (co)polymères biodégradables d'architectures variées by Aline Couffin( Book )

2 editions published in 2013 in French and held by 2 WorldCat member libraries worldwide

This work is based on a collaboration between the French chemical company Arkema -Groupement de Recherches de Lacq (GRL) and LHFA located in Toulouse. This work consists in developing organocatalytic systems for the preparation of (co)polymers, via ring opening polymerization (ROP), of various monomers. In a first chapter, the copolymerization of e-caprolactone (e-CL) and trimethylenecarbonate (TMC) catalyzed by sulfonic acids is presented. The efficiency of the catalytic system afforded access to well-defined copolymers: blocks and gradients. The study focused on the influence of the operating conditions on the structure of the copolymer and its impact on the copolymer microstructure regarding thermal properties. In a second chapter, the study of sulfonic acid has been transposed to the ROP of beta- butyrolactone (beta-BL). A precise understanding of the polymerization mechanisms allowed us to prepare polybutyrolactones with controlled molecular weights and structures. Copolymerization of e- CL and beta-BL was also studied. Moreover, we have described defined tri- and penta-block structures in the presence of different type of (macro) initiators by an organocatalytic system: triflic acid. The third chapter describes new organocatalytic systems for the controlled ROP of e-CL: phosphoric acids. Experimental results suggest a bifonctionnal activation mode, which is supported by a theoretical study led by Laurent Maron's team in LCPNO. The structure of the catalysts was then modified in order to achieve a stereocontrolled ROP of chiral monomers such as lactide and beta- butyrolactone. Nevertheless, and despite some improvements in terms of catalyst activity, the polymerization remained so far unstereoselective. Finally, in the fourth chapter, phenomena of association between a chiral Brønsted acid and D, L-lactide were identified by spectroscopic studies. The use of this chiral acid as a chiral solvating agent, gives access to an accurate determination of enantiomeric excess of a wide range of monomers used in ROP
Cooperative catalysis by 2-indenediide pincer complexes by Diandian Ke( Book )

2 editions published in 2016 in English and held by 2 WorldCat member libraries worldwide

Cette thèse décrit l'étude réalisée sur des complexes portant le ligand pince indendiide, incluant leur synthèse et caractérisation ainsi que leur activité en catalyse coopérative métal/ligand de cycloisomérisation d'acide alcynoïques et N-tosyl alkynylamides. Le premier chapitre fait un point bibliographique non-exhaustif du domaine de la catalyse coopérative métal/ligand, des premiers travaux précurseurs de Noyori sur les processus d'hydrogénation avec des complexes amido de ruthénium aux récents travaux de Milstein avec des complexes pince à base de pyridine déaromatisée. Le deuxième chapitre porte sur le développement de nouveaux complexes pince indendiide du Pd et leur application en catalyse coopérative métal/ligand. La modification structurale réalisée, remplacement des substituants Ph sur l'atome de phosphore par des iPr, visait à augmenter la robustesse des complexes et améliorer ainsi leur performance en catalyse. Deux nouveaux complexes ont été préparés et entièrement caractérisés (RMN, IR, DRX). Les premières évaluations d'activité catalytique ont en effet révélé une meilleure activité de ces nouveaux complexes comparés à leurs prédécesseurs, puisqu'ils sont capables de cycloisomériser de manière efficace les N-tosyl alkynyl amides. Une large gamme de substrats a été étudiée, incluant N-tosyl alkynyl amides linéaires non-substituées et substituées, d'autres à base de squelette phénylène, et même celles à alcyne en position interne. De manière générale, une majorité d'exo-lactames est formée avec des très bons rendements (~90%) sauf lorsque l'alcyne est en position interne, cas dans lequel l'endo-lactame est formée préférentiellement. Il est important de souligner que le résultat phare de ce chapitre est la préparation pour la première fois de methylène lactames à 7-chainons par cycloisomérisation. Malgré les avancées notables atteintes dans ce chapitre, la grand modularité des complexes pince étudiés permet d'espérer des améliorations du système catalytique. Ces améliorations sont présentées lors du troisième chapitre. Il s'agit ici de remplacer l'atome de Pd par le Pt. Les nouveaux complexes préparés ont été évalués dans la cycloisomérisation de acides alcynoïques et N-tosyl alcynyl amides et le meilleur d'entre eux a été identifié (dimère à groupement iPr sur l'atome de P). A nouveau une large gamme de substrats, acides et amides, a été étudiée faisant varier la taille de cycle et la position de l'alcyne. La stratégie s'est avérée fructueuse puisque de manière générale ce complexe de Pt s'est montré plus actif que l'équivalent à base de Pd. En particulier, ce complexe présente une activité remarquable pour la transformation d'alcynes internes et la formation de cycles à 6 et 7-chaînons. La connaissance approfondie du mécanisme de la réaction a conduit aussi à l'utilisation d'additifs donneurs de liaison H afin de favoriser la réaction de cyclisation. Grâce à l'utilisation du pyrogallol, la vitesse de réaction et la sélectivité 6-endo (vs 5-exo) et 6-exo (vs 7-endo) ont été améliorées de manière significative. Pour la première fois, une grande variété de d et e-lactones et lactames ont pu être préparées avec des très bonnes sélectivités et rendements. L'ensemble de ces résultats souligne les propriétés uniques de ces complexes pince indendiide et étend leurs applications catalytiques
Complexes pince et cooperativité métal/ligand : application en catalyse by Paul Brunel( Book )

2 editions published in 2018 in French and held by 2 WorldCat member libraries worldwide

This Ph.D. work deals with organometallic chemistry of indenyl/indenediide palladium and platinum pincer complexes and their applications in metal-ligand cooperative catalysis. The first chapter of this manuscript compiled a non-exhaustive bibliographic survey of the field of metal-ligand cooperation, from Noyori's system applied to the asymmetric hydrogenation, to the recent examples described by Milstein involving non-aromatic pincer ligands. Pincer ligands are also presented. Starting from the first example, in which Shaw shed light a PCP pincer, to the contemporary CNC pincer reported by Bezuidenhout. The versatility of those ligands is illustrated through few modulations allowing originals reactivities or stabilisation of highly unstable species. The second chapter is focused on the development of a new catalytic reaction with the indenediide palladium pincer complex. This reaction entail, for the first time, two substrates, the CO2 as a C1 source and propargylamines/homopropargylamines. The mechanistic studies turn out the importance of the metal-ligand cooperativity. Then, the third chapter concerns exploratory chemistry. New reactivities have been studied with the platinum complexes. The activation of low polar bond such as H-H and H-Si allowed the reduction of unsatured C-C bond. The mechanistic propositions, that remain to be confirmed, seem to indicate the feasibility of ? bond metathesis and migratory insertions. Finally, the last chapter is dedicated to the development of a new ligand. The latter showed the distinctive characteristic to be hemilabile, leading the way of new reactivities. His coordination to palladium, followed by his deprotonation to give rise to the non-innocent nature of the complex is presented, as well as the application of the resulting complex in the context of a cycloisomerisation. Those results are reflecting the importance of the indenyl and indenediide pincer ligands besides the metal-ligand cooperativity in catalysis
Valorisation des Dérivés Carboniques par hydrogénation : un challenge vers le développement de procédés éco-compatibles by Sebastien Coufourier( )

2 editions published in 2018 in French and held by 2 WorldCat member libraries worldwide

The use of carbon dioxide as a source of carbon C1 to produce chemical platforms or as a fuel source constitute an alternative to petrochemicals and could allow its recycling. Currently, the main described processes for the recycling and the valorization of CO2 are using reducing agents in stoichiometric amounts (which generates waste) or noble metals (limited availability, toxicity and high costs). In this environmental and economical race, one of the challenges of modern chemistry is the preparation of new organometallic iron complexes and their use in catalysis. Based on our expertise in the field of synthesis, catalysis and development of organometallic complexes, this work proposes to develop new fast, efficient, selective and eco-compatible methodologies for the reduction of carbon dioxide and carbonates by hydrogenation with bifunctional iron complexes
Catalyse organique de polymérisation d'hétérocycles : application à la synthèse de modifiants polymères biodégradables by Damien Delcroix( Book )

2 editions published in 2011 in French and held by 2 WorldCat member libraries worldwide

This work is based on a collaboration between Arkema - Groupement de Recherches de Lacq (GRL) and LHFA in Toulouse. Catalytic systems with original mode of activation have been developped for the ring-opening polymerization of various monomers. The polymerization processes have been optimized in the laboratory and scaled-up at the GRL. In a first chapter, the ring-opening polymerization (ROP) of e-caprolactone (e-CL) catalyzed by sulfonic acids is presented. A very good control is reached upon the polymerizations and allows the synthesis of well-defined poly(caprolactone) with masses up to 20 000 g/mol. An original mode of action is suggested by these experimental results and the mechanisms of polymerization are identified to be bifonctional based on an theoretical study lead by Laurent Maron's team in LCPNO. In a second chapter, the same catalytic system is successfully transposed to the ROP of Triméthylènecarbonate (TMC). A precise compréhension of the polymerization mechanisms allows us to prepare polycarbonates with controlled masses and structures. The copolymerization of TMC and e-CL is also investigated. We describe the structures of copolymers available through a methanesulfonic acid catalyzed copolymerization. The thermic properties of the synthetized copolymers are characterized by DSC. The third chapter introduces new catalytic systems for the ROP of e-CL : phosphoric acids and their derivatives. Experimental suggest again a bifonctionnal activation mode, which is supported by a theoretical study. These catalysts are further employed to achieve a stereocontrolled ROP of chiral monomers. Eventually, in the fourth chapter, a sequential ROP of two different monomers (esters and cyclic siloxanes) is described for the synthesis of thermoplastic elastomers composed of polysiloxanes and polylactide for precise applications in the industrial field
Synthèse de lactones fonctionnalisées par réaction de thiol-ène et leur application à la préparation de polymères biodégradables de propriétés modulables by Somprasong Thongkham( Book )

2 editions published in 2019 in English and held by 2 WorldCat member libraries worldwide

The development of new sustainable polymers endowed with improved performances but minimal environmental impact has become a major concern. In this context, aliphatic polyesters are attracting increasing attention in the medical field and packaging applications, due to their biodegradable character and suitable physical properties. Ring-opening polymerization (ROP) is a method that has been used in these areas to access a broad range of polyesters with different and well-controlled structures. One of the well-known lactone monomers for ROP is epsilon-caprolactone (epsilon-CL), a compound derived from petrochemical source. An alternative lactone monomer derived from biomass is epsilon-decalactone (epsilon-DL). Being a 7-membered ring as epsilon-CL, epsilon-DL is thus a renewable monomer that is attracting increasing attention. However, the pendant butyl group at epsilon-position has a large impact on mechanical and thermal properties as well as degradation rates. To modulate these properties, we have been working with the functionalized monomers of close structure to ensure similar behavior in ROP. First, the epsilon-functionalized-epsilon-CL monomers were prepared from 6-heptynoic acid by a sequential transition metal catalyzed cycloisomerization and subsequent thiol-ene reaction. Afterwards, their copolymerization with epsilon-DL has been explored including the identification of controlled/living polymerization using InCl3-based bicomponent catalyst and the confirmation of their random architecture. In addition, the preparation of copolymers featuring pendant carboxyl groups by post-modification steps have also been completely achieved. Finally, the hydrolytic and enzymatic degradation of these functionalized copolymers has been thoroughly investigated, proving the influence of our new functionalized monomer (in deprotected form) on degradation rates of PDL
Nouveaux complexes pince indényle et indolyle de palladium : préparation et réactivité by Jérôme Lisena( Book )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

The aim of this thesis is to develop and study a new family of pincer complexes based on indene and indole skeletons. In recent years, pincer complexes commanded much attention in the field of organometallic chemistry. Many important applications and properties were discovered and this contributes to the dynamic in the development of new pincer structures. The first chapter presents a bibliographic introduction of pincer complexes, the principal way of preparation and some original applications (catalysis, high reactive compound stabilization, mechanistic studies). Then, the development of the indenyl pincer complexes in the LBPB group of the LHFA is introduced. The second chapter contains the synthesis of SCS indenyl and indenylidene palladium (II) complexes. A mechanistic study of the formation of these complexes shows that the Csp3-H bond is activated preferentially compared to the Csp2-H bond. Therefore, a methyl substituted ligand is prepared in order to block the pathway of Csp3-H bond activation. It demonstrates the feasibility of the direct activation of the central Csp2-H with subsequent formation of a methylindenyl palladium complex. In the third chapter, a new ligand structure is developed starting from the indole skeleton. This new pro-ligand completes the serie of indenyl, indolyl and indenylidene complexes, which exhibit a range of different structural and electronic properties. Finally, the non-innocent character of this new complex is studied and proves the inertia of the lone pair of the nitrogen. In the last chapter, the influences of the three platforms are compared from a structural point of view, in all cases with the PPh3 co-ligand. The electronic properties are examined using carbon monoxide as spectroscopic probe. Hydroamination of acrylonitrile and allylation of imine are then carried out to distinguish the systems according to their electronic properties and their mechanism
Organo-Polyoxometalates for acid catalysis : a combined experimental/modeling study by Debora Vilona( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

Polyoxometalates (POMs) are anionic nano-molecules made by highly oxidized metals and oxygen, whose structure can be easily controlled changing synthetic conditions. Thanks to their robustness, simple POMs are regularly used in industrial processes as Brønsted acids or oxidants. With the aim to rationally design new hybrid POM-based Brønsted acid catalysts for asymmetric catalysis (artificial enzymes), we functionalized the inorganic framework (P2W15V3O62)9- with organic moieties (amides and ureas) to understand how the POM can influence the acid activity of the organo ligands. We established that the POM allows to improve the acidity of the protons in the organo-ligands thanks to its electrowithdrawing character and its property to act as electron reservoir.In parallel, the lacunary (?1/?2-P2W17O61)10- POMs were functionalized with polyglycines chains of different lengths to understand through high-field NMR studies and Molecular Dynamics simulations which are the critical factors governing the intramolecular interactions in solution between polypeptides and the POM surface. The polyoxometalate rigidifies the peptide chains, acting as H-bonding acceptor versus the amidic protons of the lateral chain. We also demonstrated that the interaction is a function of the peptide chain length, the lacuna position on the POM and the amidic proton position on the lateral chain
Nouveaux complexes pince indényle et indolyle de palladium préparation et réactivité by Jérôme Lisena( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

The aim of this thesis is to develop and study a new family of pincer complexes based on indene and indole skeletons. In recent years, pincer complexes commanded much attention in the field of organometallic chemistry. Many important applications and properties were discovered and this contributes to the dynamic in the development of new pincer structures. The first chapter presents a bibliographic introduction of pincer complexes, the principal way of preparation and some original applications (catalysis, high reactive compound stabilization, mechanistic studies). Then, the development of the indenyl pincer complexes in the LBPB group of the LHFA is introduced. The second chapter contains the synthesis of SCS indenyl and indenylidene palladium (II) complexes. A mechanistic study of the formation of these complexes shows that the Csp3-H bond is activated preferentially compared to the Csp2-H bond. Therefore, a methyl substituted ligand is prepared in order to block the pathway of Csp3-H bond activation. It demonstrates the feasibility of the direct activation of the central Csp2-H with subsequent formation of a methylindenyl palladium complex. In the third chapter, a new ligand structure is developed starting from the indole skeleton. This new pro-ligand completes the serie of indenyl, indolyl and indenylidene complexes, which exhibit a range of different structural and electronic properties. Finally, the non-innocent character of this new complex is studied and proves the inertia of the lone pair of the nitrogen. In the last chapter, the influences of the three platforms are compared from a structural point of view, in all cases with the PPh3 co-ligand. The electronic properties are examined using carbon monoxide as spectroscopic probe. Hydroamination of acrylonitrile and allylation of imine are then carried out to distinguish the systems according to their electronic properties and their mechanism
Catalyse organique de polymérisation par ouverture de cycle synthèse de polymères biodégradables à visée pharmacologique by Aurélie Alba( )

1 edition published in 2012 in French and held by 1 WorldCat member library worldwide

This work is in line with a collaboration between the galenical centre of Ipsen Pharma based in Barcelona (Spain) and the LHFA in Toulouse. New PLGA supports have been synthesized by organocatalysis at Toulouse and then formulated by Ipsen Pharma. In the first chapter, the synthesis of PLGA oligomers using an acidic catalyst is described, as well as multiple analytical techniques to determine the chemical and physico-chemical properties of the polymers. In order to better apprehend the results observed in formulation, some structure/activity relationship studies have been performed. The scale up of the polymerizations was also investigated, as well as the stability and tolerance of the polymers. In the second chapter, acidic or basic catalysts were used to synthesize hyperbranched macromolecular systems (star shape or dendrimer), still by ring opening of lactide and using multifunctional initiators (alcohols and/or amines). In the third chapter, a new bifunctional catalytic system consisting of a triflamide or sulfonamide, as hydrogen bond donor, and a tertiary amine, as hydrogen bond acceptor was screened and applied to the ROP of lactide. A bis-sulfonamide-DMAP couple is preferred for the preparation of well controlled PLA under mild conditions. Moreover, a range of mono-sulfonamide and bis-sulfonamide with different spacers were synthesized to undergo kinetic studies and determine the way of action of the catalyst. The two NH groups were shown to activate the monomer cooperatively, while the protic initiator is activated by the DMAP. In the fourth chapter, a new chiral derivatizing agent (CDA), named NaphtOCA, is synthesized and applied to the absolute configuration assignment of an a-chiral primary amine by 1H NMR spectroscopy. The NaphtOCA reacts immediately with an amine, without any coupling agent used, to generate an amide and an hydroxyl group. The way of action of this effective CDA was fully investigated
Radical and catalytic polymerizations of alpha-olefins : towards CO2-incorporation by Ali Al Rida Hmayed( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

This thesis focuses primarily on the utilization of CO2 in radical and catalytic polymerizations of a-olefins. Polyethylene was synthesized by a free radical polymerization process in supercritical CO2 (scCO2) under mild conditions (T? 100 °C, P? 300 bar) without addition of any initiator diluent, using AIBN, lauroyl peroxide, or benzoyl peroxide to investigate different initiation modes. The decarboxylation of the latter can be suppressed in scCO2 to yield ester-functionalized polyethylene. Furthermore, an interaction between triethylaluminum (AlEt3) and radicals was unveiled, the effect of AlEt3 on ethylene radical polymerization was investigated showing its role as an irreversible chain-transfer agent in this process. This interaction in conjunction with the reactivity of AlEt3 towards CO2 were harnessed to allow for CO2-incorporation within polyethylene chains. Thus, since CO2 was incorporated within the polyethylene chains using AlEt3, CO2 for the first time behaved as an effective reagent in ethylene radical polymerization. On the other hand, ethylene-isoprene random and block copolymerizations via iron-catalyzed chain shuttling processes have been achieved. Subsequently, each monomer was polymerized in supercritical CO2 using its corresponding dedicated iron catalyst in order to achieve sustainable processes to polymerize these monomers with the hope of incorporating some carboxylic moieties. Trials to functionalize polyolefins by CO2 using various strategies is an area of interest in the upcoming work of our laboratory
Contribution à la chimie de complexes tri- et di-nucléaires du fer apparentés au site actif des hydrogénases [FeFe] by Ahmad Hobballah( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

The studies described in this thesis is a continuation of those conducted in the laboratory namely the development of iron complexes, models of the active site named H-cluster of the [FeFe]-hydrogenase, a metalloenzyme capable of forming or activating the molecular hydrogen. A series of diiron and triiron complexes with different dithiolate and diphosphine ligands has been synthesized. Each complex was characterized by a wide range of spectroscopic techniques, 1H and 31P{1H} NMR, IR and X-ray diffraction. Their electrochemical behavior was studied by cyclic voltammetry. The first part of this manuscript is devoted to triiron complexes which are not strictly structural models of the H-cluster, but which nonetheless possess some of its characteristics. The effects of dithiolate bridges, more or less bulky or containing a nitrogen atom at the bridgehead, are compared and the reactivity of the complexes as well as their behaviour towards substrates such protons are presented. The introduction of a pendant base via a diphosphine of P 2N 2 type, (R= Ph or Bn) was considered in the case of triiron complexes but also in the case of diiron ones. The studies carried out on these latter compounds are developed in the second part of this thesis. The impact of the R group of diphosphine on the protonation of complexes and on their oxidation is highlighted. In particular, it has been demonstrated for the complexes PPh2NBn2 that a one-electron oxidation triggers an intramolecular activation of a CH bond which leads via a mechanism involving a proton exchange and a second electron transfer to novel cationic species
Création de liaisons C-C et C-N par transformation catalytique du CO et du CO₂ by Tawfiq Nasr Allah( )

1 edition published in 2018 in French and held by 1 WorldCat member library worldwide

Hormis la préparation de l'acide salicylique et de l'urée, peu de tentatives ont été réalisées jusqu'à présent pour promouvoir la formation de liaisons C-C et C-N à partir du CO₂. Cette thèse présente de nouveaux procédés catalytiques permettant la formation de molécules organiques azotées grâce à la création de liaisons C-N et C-C par transformation catalytique du CO et du CO₂. Les cibles retenues sont les amides ainsi que les alkylamines qui sont essentiels en chimie organique fine et sont souvent d'origine pétrosourcés. Dans un premier temps, la synthèse d'amide par carbonylation formelle de la liaison C-N d'amine sera étudiée grâce à des catalyseurs à base de métaux carbonyles. Dans un second temps, des procédés d'homologation des amines seront décrits grâce à l'utilisation de catalyseurs métalliques. La première stratégie impliquera l'utilisation de catalyseur de cobalt, en présence de CO et de silanes et permettra l'homologation sélective des liaisons N-méthyle en N-éthyle sous de faible pression de CO (P = 8 bar) et jusqu'au N-pentyle sous de fortes pressions. Dans un second temps, l'utilisation d'un catalyseur de ruthénium en présence d'un gaz de synthèse (CO/H₂) nous permettra de démontrer la possibilité de l'homologation de la diphénylamine. Enfin, la compréhension de ce système nous permettra de transposer cette réaction à l'utilisation du CO₂ comme substitut du CO
Conception et synthèse de molécules-modèles pour surfaces isolantes by Adeline Pujol( Book )

1 edition published in 2012 in French and held by 1 WorldCat member library worldwide

The understanding of the behaviour, at atomic scale, of molecules on insulating surfaces is one of pre-requisites to devising molecular nanomachines with electrical addressing. But in these conditions, the interaction between organic molecules and surface is extremely weak, leading to the diffusion of species on surface at high speed and also to 3D clustering. The aim of this thesis has been to design and to synthesize molecules-models tuned to maximize their interaction with insulating surfaces like potassium bromide or sodium chloride. Then the behaviour of these molecules has been studied by non-contact atomic force microscopy. These molecules-models comprise: (a) a rigid aromatic or polyaromatic core like triphenylene and pentabenzocorannulene, compound for which several original synthetic strategies have been explored. (b) several anchoring groups used to increase the molecule - substrate interactions and to reduce the diffusion of species on surface. These groups are designed to interact with local partial charges of surface. Two types of anchoring groups have been developed: on the one hand, chemical functions with a strong polar moment and on the other hand, zwitterions. These anchoring groups are connected to the aromatic platform by alkyl chains. The relative flexibility brought to the system by alkyl chains, allows the anchoring groups to find the best sites on surface, the ones for which the molecule-substrate interaction is maximized
Catalyse organique de polymérisation d'hétérocycles préparation de (co)polymères biodégradables d'architectures variées by Aline Couffin( )

1 edition published in 2014 in French and held by 1 WorldCat member library worldwide

This work is based on a collaboration between the French chemical company Arkema -Groupement de Recherches de Lacq (GRL) and LHFA located in Toulouse. This work consists in developing organocatalytic systems for the preparation of (co)polymers, via ring opening polymerization (ROP), of various monomers. In a first chapter, the copolymerization of e-caprolactone (e-CL) and trimethylenecarbonate (TMC) catalyzed by sulfonic acids is presented. The efficiency of the catalytic system afforded access to well-defined copolymers: blocks and gradients. The study focused on the influence of the operating conditions on the structure of the copolymer and its impact on the copolymer microstructure regarding thermal properties. In a second chapter, the study of sulfonic acid has been transposed to the ROP of beta- butyrolactone (beta-BL). A precise understanding of the polymerization mechanisms allowed us to prepare polybutyrolactones with controlled molecular weights and structures. Copolymerization of e- CL and beta-BL was also studied. Moreover, we have described defined tri- and penta-block structures in the presence of different type of (macro) initiators by an organocatalytic system: triflic acid. The third chapter describes new organocatalytic systems for the controlled ROP of e-CL: phosphoric acids. Experimental results suggest a bifonctionnal activation mode, which is supported by a theoretical study led by Laurent Maron's team in LCPNO. The structure of the catalysts was then modified in order to achieve a stereocontrolled ROP of chiral monomers such as lactide and beta- butyrolactone. Nevertheless, and despite some improvements in terms of catalyst activity, the polymerization remained so far unstereoselective. Finally, in the fourth chapter, phenomena of association between a chiral Brønsted acid and D, L-lactide were identified by spectroscopic studies. The use of this chiral acid as a chiral solvating agent, gives access to an accurate determination of enantiomeric excess of a wide range of monomers used in ROP
Donneurs d'électrons organiques : synthèse de nouveaux précurseurs stables à l'air et applications by Guillaume Tintori( )

1 edition published in 2020 in French and held by 1 WorldCat member library worldwide

Les réducteurs organiques de type énamine (DEOs) représentent une alternative intéressante aux photocatalyseurs métalliques et aux colorants organiques. Ces structures sont capables de transférer spontanément un (SET) ou deux électrons (DET) à des substrats organiques réputés difficiles à réduire. Cependant, ces donneurs d'électrons sont instables à l'air et/ou se décomposent rapidement du fait de leur temps de vie très court, perdant ainsi leurs capacités réductrices. Pour répondre à cette problématique, nous avons développé plusieurs stratégies de génération in situ de DEOs à partir de précurseurs carboxylates stables à l'air. La décarboxylation du 4-(diméthylamino)-1-méthylpyridinium-2-carboxylate , sous activation thermique (150°C), et du 1,3-diméthylbenzimidazolium-2-carboxylate BzIMe-CO2 à température ambiante dans un mélange 5% H2O/1,4-dioxane, génère respectivement le di-pyridin-2-ylidène et le di-1,3-diméthylbenzimidazolin-2-ylidène. Ces deux réducteurs promeuvent la réduction de fonctions halogènes et sulfones sur des substrats diversement fonctionnalisés. Ces précurseurs facilitent l'accès aux DEOs tout en conservant leurs réactivités.Le développement de nouveaux précurseurs nous a également conduit aux adduits isoquinoléines trihalogénométhylés Iso-CCl3 et Iso-CF3. Activables sous irradiation lumineuse (lumière visible ou UV), ces précurseurs, stables à l'air, génèrent respectivement des intermédiaires radicalaires ou une forme excitée réductrice, capables d'induire la polymérisation radicalaire de nombreux monomères. La réduction de dérivés bromobenzyles et d'iodures d'aryle par transfert d'électrons est également accessible avec l'adduit trifluorométhylé
 
moreShow More Titles
fewerShow Fewer Titles
Audience Level
0
Audience Level
1
  General Special  
Audience level: 0.00 (from 0.00 for Activation ... to 0.00 for Activation ...)

Languages
French (19)

English (10)