Vers le contrôle de la chiralité axiale des (hétéro)biaryles en l’absence de métaux de transition via le couplage

The aim of this thesis work was to provide novel access to axially chiral heterobiaryls following a transition metal free atropoenantioselective synthetic route. This project combines the Csp2-Csp2 Aryne coupling methodology, and an enantioselective approach, the ICE concept (ionic chiral environment). This concept relies on the implementation of chiral ligands as metal (Li) stabilizers with organolithium coupling partners. The chiral environment resulting from the chiral aggregates obtained must induce chirality during the coupling step. The first part of this work aimed to develop an heterocyclic version of the Aryne route in achiral conditions. The results of this study revealed a clear correlation between the electronic nature of the heterocyclic partner and its reactivity in the Aryne coupling. Thiophene, especially, proved to furnish promising results and allowed us to further develop the method. Second part of this work aimed to develop the reaction in the appropriate solvent conditions so that chiral mixed metal aggregates could be envisioned. This study outlined the remarkable effect of external chelating ligands (polyethers, polyamines, aminoalkoxides,…) and salt additives (Li, Zn, K,…) on the aryne coupling reaction in apolar media. The best reaction conditions emerging from this work were then successfully applied to others heterocyclic coupling partners. In parallel, theoretical calculations using density functional theory showed good agreement with experimental work and allowed us to propose mechanistic scheme for the reaction. Last part of this work focused on the reaction of hindered heterocyclic coupling partners with thiophene and benzothiophene derivativesL’objectif de ce travail de thèse est de développer une nouvelle voie d’accès aux hétérobiaryles à chiralité axiale selon une stratégie de synthèse atropoénantiosélective réalisée en l’absence de métaux de transition. Le projet combine une méthode de construction de la liaison Csp2-Csp2 appelée couplage Aryne, et une approche énantiosélective, le concept ICE (ionic chiral environment). Ce concept repose sur la mise en œuvre de ligands chiraux en tant que stabilisants du métal (Li) à partir d’un partenaire de couplage organolithié. L’environnement chiral résultant des agrégats chiraux générés doit permettre d’induire la chiralité lors de l’étape de couplage. La première partie de ce travail a consisté à développer une version hétérocyclique du couplage Aryne en conditions achirales. Les résultats obtenus à l’issue de cette étude ont permis de relier la nature électronique du partenaire hétérocyclique à sa réactivité dans le couplage. Le thiophène en particulier a fourni de très bons résultats ce qui nous a permis de développer davantage la méthode. La seconde partie de ce travail a eu pour objectif de développer le couplage étudié dans des conditions de solvants adaptées à la formation des agrégats mixtes chiraux envisagés. Cette étude a permis de mettre en évidence l’influence remarquable d’une gamme de plusieurs ligands (polyéthers, polyamines, aminoalcoolates,…) et sels (Li, Zn, K,…) sur le couplage développé en solvant apolaire. Par la suite, les conditions de couplages optimales ont été étendues à différents hétérocycles avec succès. En parallèle, des calculs théoriques de la densité fonctionnelle ont permis d’appuyer plusieurs de nos résultats ; ces calculs ont également fourni une analyse détaillée du mécanisme du couplage Aryne. Enfin, la dernière partie de ce manuscrit a concerné le couplage d’un partenaire hétérocyclique encombré des dérivés du thiophène et du benzothiophèn

Towards the control of heterobiaryl axial chirality in the absence of transition metal via the Aryne coupling

L’objectif de ce travail de thèse est de développer une nouvelle voie d’accès aux hétérobiaryles à chiralité axiale selon une stratégie de synthèse atropoénantiosélective réalisée en l’absence de métaux de transition. Le projet combine une méthode de construction de la liaison Csp2-Csp2 appelée couplage Aryne, et une approche énantiosélective, le concept ICE (ionic chiral environment). Ce concept repose sur la mise en œuvre de ligands chiraux en tant que stabilisants du métal (Li) à partir d’un partenaire de couplage organolithié. L’environnement chiral résultant des agrégats chiraux générés doit permettre d’induire la chiralité lors de l’étape de couplage. La première partie de ce travail a consisté à développer une version hétérocyclique du couplage Aryne en conditions achirales. Les résultats obtenus à l’issue de cette étude ont permis de relier la nature électronique du partenaire hétérocyclique à sa réactivité dans le couplage. Le thiophène en particulier a fourni de très bons résultats ce qui nous a permis de développer davantage la méthode. La seconde partie de ce travail a eu pour objectif de développer le couplage étudié dans des conditions de solvants adaptées à la formation des agrégats mixtes chiraux envisagés. Cette étude a permis de mettre en évidence l’influence remarquable d’une gamme de plusieurs ligands (polyéthers, polyamines, aminoalcoolates,…) et sels (Li, Zn, K,…) sur le couplage développé en solvant apolaire. Par la suite, les conditions de couplages optimales ont été étendues à différents hétérocycles avec succès. En parallèle, des calculs théoriques de la densité fonctionnelle ont permis d’appuyer plusieurs de nos résultats ; ces calculs ont également fourni une analyse détaillée du mécanisme du couplage Aryne. Enfin, la dernière partie de ce manuscrit a concerné le couplage d’un partenaire hétérocyclique encombré des dérivés du thiophène et du benzothiophèneThe aim of this thesis work was to provide novel access to axially chiral heterobiaryls following a transition metal free atropoenantioselective synthetic route. This project combines the Csp2-Csp2 Aryne coupling methodology, and an enantioselective approach, the ICE concept (ionic chiral environment). This concept relies on the implementation of chiral ligands as metal (Li) stabilizers with organolithium coupling partners. The chiral environment resulting from the chiral aggregates obtained must induce chirality during the coupling step. The first part of this work aimed to develop an heterocyclic version of the Aryne route in achiral conditions. The results of this study revealed a clear correlation between the electronic nature of the heterocyclic partner and its reactivity in the Aryne coupling. Thiophene, especially, proved to furnish promising results and allowed us to further develop the method. Second part of this work aimed to develop the reaction in the appropriate solvent conditions so that chiral mixed metal aggregates could be envisioned. This study outlined the remarkable effect of external chelating ligands (polyethers, polyamines, aminoalkoxides,…) and salt additives (Li, Zn, K,…) on the aryne coupling reaction in apolar media. The best reaction conditions emerging from this work were then successfully applied to others heterocyclic coupling partners. In parallel, theoretical calculations using density functional theory showed good agreement with experimental work and allowed us to propose mechanistic scheme for the reaction. Last part of this work focused on the reaction of hindered heterocyclic coupling partners with thiophene and benzothiophene derivative

Migrations résidentielles et périurbanisation en Ile-de-France

Between 1975 and 1982 population migration into the outer suburbs occupied a modest place, if one compares it to the migration recorded within the Greater Paris area : 80 % of the area's migrants who left their communities moved to another community in the area, and only 10 % moved to outlying areas. The socioprofessional categories of executives and members of the intermediate professions are overrepresented among the immigrants into the outer suburbs, even if the total numbers of workers and employees are also quite positive. Thus, unlike what occurs in the center of the metropolitan area, there is no increase in the proportion of well-to-do classes brought about by the «expulsion» of the more modest classes.Entre 1975 et 1982, les migrations de population à destination de la couronne périurbaine occupent une place modeste, si on les compare aux migrations enregistrées au sein de l'agglomération parisienne : 80% des migrants de l'agglomération ayant quitté leur commune se sont déplacés vers une autre commune de l'agglomération, et seulement 10% se sont dirigés vers la couronne périurbaine. Les catégories socioprofessionnelles des cadres et des professions intermédiaires sont suireprésentées parmi les immigrants en couronne périurbaine, même si les soldes d'ouvriers et d'employés sont également très positifs. Ainsi, contrairement au centre de l'agglomération, l'augmentation de la part des catégories aisées n'est pas amplifiée par 1'«expulsion» des catégories plus modestes.Demangeat Daniel, Lefort Catherine. Migrations résidentielles et périurbanisation en Ile-de-France. In: Villes en parallèle, n°19, juin 1992. Les périurbains de Paris. pp. 28-45

Recent advances in room temperature phosphorescence of chiral organic materials

International audienceRoom temperature phosphorescence (RTP) in purely organic materials is an uncommon phenomenon of emission, which can be characterized by a long persistent luminescence after removal of the excitation source. In the recent years, RTP organic materials have received a considerable attention due to their high application potential in various advancing technologies, ranging from optoelectronic to biomedical applications. In parallel, many progresses have been achieved on the rationalization of this process and led to the emergence of innovative strategies aiming to achieve highest performances both in terms of phosphorescence efficiency and lifetime. While the topic is still on an ascendant development, the generation of circularly polarized phosphorescent (CPP) emission from purely organic molecules is by far much less explored and remains an impressive challenge. Still, the perspective of CPP materials appears as an interesting opportunity to answer several comprehensives issues existing in the field. In this article, we define, in a straightforward way, basic principles and key notions for the generation of RTP and CP luminescence (CPL) guiding the design toward CPP materials. After this brief insight, recent advances in the field of chiral organic RTP materials are discussed with an emphasis on their CP-RTP properties. Based on this development, the conclusion drawn allows establishing the next challenges and future opportunities standing in the field

Transition-Metal-Free Heterobiaryl Synthesis via Aryne Coupling

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Transition-Metal-Free Approach for the Direct Arylation of Thiophene: Experimental and Theoretical Investigations towards the (Het)-Aryne Route

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Necessary and sufficient condition for organic room-temperature phosphorescence from host-guest doped crystalline systems.

Controlling and predicting the long-lived room temperature phosphorescence (RTP) from organic materials are the next challenges to address for the realization of new efficient organic RTP systems. Here, a new approach is developed to reach these objectives by considering host-guest doped crystals as well-suited model systems in that they allow the comprehensive understanding of synergetic structural interactions between crystalline host matrices and emitting guest molecules, one of the key parameters to understand the correlation between the solid-state organization and crystal RTP performances. We designed two series of sigma-conjugated donor/acceptor (D-sigma-A) carbazole-based matrices and isomeric 1H-benzo[f]indole-based dopants, capable of exploring a wide variety of conformations thanks to large rotational degrees of freedom provided by the sigma-conjugation. By correlating results of single-crystal X-ray diffraction analysis and photoluminescence properties, we established a necessary and sufficient condition for RTP that paves the way for the development of new long-lived RTP host-guest doped systems

σ‐Conjugation and H‐Bond‐Directed Supramolecular Self‐Assembly: Key Features for Efficient Long‐Lived Room Temperature Phosphorescent Organic Molecular Crystals

International audienceLong-lived room temperature phosphorescence from organic molecular crystals attracts great attention. Persistent luminescence depends on the electronic properties of the molecular components, mainly p-conjugated donoracceptor (D-A) chromophores, and their molecular packing. Here, a strategy is developed by designing two isomeric molecular phosphors incorporating and combining a bridge for s-conjugation between the D and A units and a structuredirecting unit for H-bond-directed supramolecular self-assembly. Calculations highlight the critical role played by the two degrees of freedom of the s-conjugated bridge on the chromophore optical properties. The molecular crystals exhibit RTP quantum yields up to 20 % and lifetimes up to 520 ms. The crystal structures of the efficient phosphorescent materials establish the existence of an unprecedented well-organization of the emitters into 2D rectangular columnar-like supramolecular structure stabilized by intermolecular H-bonding

Spin-orbital coupling and slow phonon effects enabled persistent photoluminescence in organic crystal under isomer doping

International audienceWhen periodically packing the intramolecular donor-acceptor structures to form ferroelectric-like lattice identified by second harmonic generation, our CD49 molecular crystal shows long-wavelength persistent photoluminescence peaked at 542 nm with the lifetime of 0.43 s, in addition to the short-wavelength prompt photoluminescence peaked at 363 nm with the lifetime of 0.45 ns. Interestingly, the long-wavelength persistent photoluminescence demonstrates magnetic field effects, showing as crystalline intermolecular charge-transfer excitons with singlet spin characteristics formed within ferroelectric-like lattice based on internal minority/majority carrier-balancing mechanism activated by isomer doping effects towards increasing electron-hole pairing probability. Our photoinduced Raman spectroscopy reveals the unusual slow relaxation of photoexcited lattice vibrations, indicating slow phonon effects occurring in ferroelectric-like lattice. Here, we show that crystalline intermolecular charge-transfer excitons are interacted with ferroelectric-like lattice, leading to exciton-lattice coupling within periodically packed intramolecular donor-acceptor structures to evolve ultralong-lived crystalline light-emitting states through slow phonon effects in ferroelectric light-emitting organic crystal

Experimental evidence of REE size fraction redistribution during redox variation in wetland soil

International audienceThe evolution of rare earth element (REE) speciation between reducing and oxidizing conditions in a riparian wetland soil was studied relative to the size fractionation of the solution. In all size fractions obtained from the reduced and oxidized soil solutions, the following analyses were carried out: organic matter (OM) characterization, transmission electron microscopy (TEM) observations as well as major and trace element analyses. Significant REE redistribution and speciation evolution between the various size fractions were observed. Under reducing conditions, the REEs were bound to colloidal and dissolved OM (2 μm size fraction), colloidal (<2 μm size fraction), organic and Fe-enriched fractions. In the particulate size fraction, the REEs were bound to humic and bacterial OM embedding Fe nano-oxides. The resulting REE pattern showed a strong enrichment in heavy REEs (HREEs) in response to REE binding to specific bacterial OM functional groups. In the largest colloidal size fraction (0.2 μm–30 kDa), the REEs were bound to humic substances (HS). The lowest colloidal size fraction (<30 kDa) is poorly concentrated in the REEs and the REE pattern showed an increase in the middle REEs (MREEs) and heavy REEs (HREEs) corresponding to a low REE loading on HS. A comparison of the REE patterns in the present experimental and field measurements demonstrated that, in riparian wetlands, under a high-water level, reducing conditions are insufficient to allow for the dissolution of the entire Fe nano-oxide pool formed during the oxidative period. Therefore, even under reducing conditions, Fe(III) seems to remain a potential scavenger of REEs