Search

DNA is the biomolecule that contains genetic information. Many diseases are linked to mutations in DNA that result in dysfunctional gene expression. Over the past twenty years, many efforts have been made in biochemistry to develop new tools to detect these mutations that could be interesting for biological or medical research.This thesis project is part of this dynamic and aims to develop a luminescent probe for sequence-specific detection of double-stranded DNA, establishing a proof of concept for the recognition of a double-stranded DNA of 12 selected base pairs. It is based on the development of a system composed of two zinc finger proteins capable of binding to the target DNA, each recognising one half of the sequence. For the luminescence detection, these proteins are equipped with a pair of luminophores that allow resonant Förster-like energy transfer (FRET), which is only active when the proteins are bound to the DNA. First, the chemical synthesis of a luminophore-free protein pair was developed using a native chemical ligation assembly and the recognition of the chosen sequence was demonstrated by electrophoretic mobility shift assay (EMSA) experiments. Next, several bioconjugatable lanthanide complexes were synthesised and those with the best photophysical properties were selected to be grafted onto one of the two proteins, acting as the donor for this FRET system. The second protein was functionalized with an organic fluorophore acting as a FRET acceptor. Finally, we studied by luminescence and electrophoresis (EMSA) the interaction of these proteins with DNA of different sequences and obtained a first proof of concept of the sequence-specific detection by luminescence of a double-stranded DNA of 12 base pairs.; L'ADN est la biomolécule qui contient l'information génétique. De nombreuses maladies sont liées à des mutations de l'ADN qui entraîne l'expression de gènes dysfonctionnelles. Au cours des vingt dernières années, de nombreux efforts ont été déployés en biochimie pour développer de nouveaux outils de détection de ces mutations qui pourraient trouver un intérêt pour la recherche en biologie ou en médecine.Ce projet de thèse s'inscrit dans cette dynamique avec pour but de développer des sondes luminescentes permettant la détection séquence-spécifique d'ADN double brin, en établissant une preuve de concept pour la reconnaissance d'un ADN double brin de 12 paires de bases choisies. Il repose sur la mise au point d'un système de deux protéines à doigts de zinc capable de se lier à l'ADN cible, chacune reconnaissant une moitié de la séquence. Pour la détection par luminescence, ces protéines sont équipées d'une paire de luminophores permettant un transfert d'énergie résonant de type Fôrster (FRET) actif uniquement lorsque les protéines sont fixées à l'ADN. Dans un premier temps, la synthèse par voie chimique d'une paire de protéines sans luminophore a été mise au point en utilisant un assemblage par ligation chimique native et la reconnaissance de la séquence choisie a été démontrée par des expériences de gel-retard (EMSA). Puis la synthèse de plusieurs complexes de lanthanides bioconjugables a été mise au point et ceux présentant les meilleurs propriétés photophysiques ont été retenus pour être greffés sur une des deux protéines, jouant le rôle de donneur pour ce système FRET. La deuxième protéine a été fonctionnalisée avec un fluorophore organique jouant le rôle d'accepteur FRET. Enfin, nous avons étudié par luminescence et gel-retard l'interaction de ces protéines avec des ADN de séquences différentes et obtenu une première preuve de concept de la détection séquence-spécifique par luminescence d'un ADN double brin de 12 paires de bases.

International audience; New lanthanide carboxylate compounds with two- (2D) and three-dimensional (3D) structures have been prepared by employing 2,5-bis(prop-2-yn-1-yloxy)terephthalic acid (2,5-BPTA) as an organic linker. The compounds, [Ln(C14H8O6)(C7O3H4)·2H2O]·4(H2O), Ln = Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy and [Ln(C7O3H4)3·(C3H7ON)·(H2O)]·2(H2O)(C3H7NO), Ln = La, Ce, Pr, have two- and three-dimensional structures, respectively. In all compounds, lanthanide ions are connected together, forming a dimer, which is connected by the 2,5-BPTA ligand. In the two-dimensional structure, there are two 2,5-BPTA moieties present, and in the three-dimensional structure, there are three 2,5-BPTA moieties present. The lanthanide centers are nine-coordinated, the 2D structure has a tricapped trigonal prismatic arrangement, and the 3D structure has a monocapped distorted square antiprismatic arrangement. The Pr compound forms in both 2D and 3D structures, whose formation depends on the time of the reaction (2 days─2D and 5–6 days─3D). The ligand emits in the blue region, and using the characteristic emission of Eu3+ (red) and Tb3+ (green) ions, we achieve white light emission in the (Y0.96Tb0.02Eu0.02) compound. The overall quantum yield for the white light emission is 28%. The strong green luminescence of the Tb3+-containing compound was employed to selectively sense the Cr3+ and Fe3+ ions in aqueous solution with limits of detection (LODs) at 0.41 and 8.6 ppm, respectively. The Tb compound was found to be a good heterogeneous catalyst for the Ullman-type O-arylation reaction between phenol and bromoarene with yields of 95%. Magnetic studies on the Gd-, Tb-, and Dy-containing compounds showed weak exchange interactions within the dimeric Ln2 units. The present work demonstrates the many utilities of the rare-earth-containing MOFs, especially toward white-light emission, metal-ion sensing, and heterogeneous catalysis.

International audience; The rapid development of green energy sources and new medical technologies contributes to the increased exploitation of rare earth elements (REEs). They can be subdivided into light (LREEs) and heavy (HREEs) REEs. Mining, industrial processing, and end-use practices of REEs has led to elevated environmental concentrations and raises concerns about their toxicity to organisms and their impact on ecosystems. REE toxicity has been reported, but its precise underlying molecular effects have not been well described. Here, transcriptomic and proteomic approaches were combined to decipher the molecular responses of the model organism Saccharomyces cerevisiae to La (LREE) and Yb (HREE). Differences were observed between the early and late responses to La and Yb. Several crucial pathways were modulated in response to both REEs, such as oxidative-reduction processes, DNA replication, and carbohydrate metabolism. REE-specific responses involving the cell wall and pheromone signalling pathways were identified, and these responses have not been reported for other metals. REE exposure also modified the expression and abundance of several ion transport systems, with strong discrepancies between La and Yb. These findings are valuable for prioritizing key genes and proteins involved in La and Yb detoxification mechanisms that deserve further characterization to better understand REE environmental and human health toxicity.

International audience; Two homometallic ytterbium dimers are prepared and their solution-state photoluminescence and upconversion properties are investigated. Both complexes exhibit two-photon cooperative luminescence upconversion in the visible region (lambda(em) approximate to 510 nm) upon excitation into the near-infrared Yb F-2(5/2)

Structural changes produced by irradiation have been extensively studied in compounds derived from the parent fluorite structure where cations are initially ordered and in systems where both sub-lattices do not display long-range order. The irradiation behaviour of fluorite-related oxide systems where the cations are randomly distributed but the anions are highly ordered is not quantitatively explored yet. We report on a model system Gd2Ce2O7, with a randomly occupied cation sub-lattice while an ordered anion sublattice. This compound crystallizes in a new bixbyite-type symmetry where O vacancies order on half of the vacant sites of the ideal bixbyite structure. Swift heavy ion irradiation experiments and quantitative x-ray diffraction analysis were used to study the separate response of the anion sub-lattice to radiation. We show that the topological disorder on the anion sub-lattice grows faster than that on the cation sub-lattice. While a decrease in strain is observed as a function of fluence, the variance of the strain increases due to an increase of the microdomain wall density.

The birth of magnetic resonance imaging (MRI) marks a major advance in the history of radiology. For almost 50 years, MRI has become an indispensable imaging and diagnostic tool. One of the main objectives is now to obtain better contrast and sensitivity in order to understand the biochemical and biological phenomena for better patient diagnostics, this is called molecular imaging. The principle of this discipline is to detect specific molecules, such as DNA sequences, cell markers, enzymes, reactive species ... It will then be possible, for example, to detect nascent cancers. The specific molecules are often present in very small quantities in the tissues and require imaging techniques with very good sensitivity. MRI has very good resolution but suffers from a lack of sensitivity. This is why contrast agents are added in order to gain in sensitivity. Conversely, optical imaging benefits from increased sensitivity but does not allow in-depth study. By coupling these two techniques, it would then be possible to study with precision the molecular mechanisms deep within the tissues.This thesis project was born in order to develop contrast agents based on lanthanides and non-innocent ligands that specifically respond to oxidative stress. The detection of this oxidative stress by several different techniques could be achieved using a bimodal probe which would combine the benefits of MRI and optical imaging, as good resolution and high sensitivity. In order to gain even more sensitivity, a new technique derived from MRI, called "CEST" for Chemical Exchange Saturation Transfer was born.The aim of this thesis is to provide the proof of concept of bimodal probes for the detection of reactive oxygen species by magnetic imaging and optical imaging techniques. For this, new families of lanthanide complexes with a radical or pro-radical ligand have been chemically synthesized and have been studied by different spectroscopic and electrochemical techniques. These analyzes validated the proof of concept by creating a bimodal probe showing an alteration of the signal depending on the redox state of the ligand.Key words: Medical imaging– Coordination complexes – Organic radicals – Lanthanides - Spectroscopy, La naissance de l’imagerie par résonance magnétique (IRM) marque un progrès majeur dans l’histoire de la radiologie. Depuis bientôt 50 ans, l’IRM est devenu un outil d’imagerie et de diagnostic indispensable. Un des principaux objectifs actuels est d’obtenir un meilleur contraste et une meilleure sensibilité afin de comprendre les phénomènes biochimiques et biologiques pour de meilleurs diagnostiques des patients, on parle alors d’imagerie moléculaire. Le principe de cette discipline est de détecter les molécules spécifiques d’une cible à étudier telles que des séquences d’ADN, des marqueurs cellulaires, des enzymes, des espèces réactives… Il sera alors possible par exemple, de détecter des cancers naissant. Les espèces à étudier sont souvent présentes en très faibles quantités dans les tissus et nécessitent des techniques d’imageries ayant une très bonne sensibilité. L’IRM dispose d’une très bonne résolution mais souffre d’un manque de sensibilité. C’est pourquoi des agents de contraste sont ajoutés afin de gagner en sensibilité. A contrario, l’imagerie optique bénéficie d’une sensibilité accrue mais ne permet pas une étude en profondeur. En couplant ces deux techniques, il serait alors possible d’étudier avec précision les mécanismes moléculaires au plus profond des tissus.C’est dans cette optique que ces travaux de thèse sont nés, afin de mettre au point des agents de contraste à base de lanthanides et de ligands non innocents répondant spécifiquement au stress oxydant. La détection de ce stress oxydant par plusieurs techniques différentes pourrait être réalisée à l’aide de sonde bimodale qui allierait les bénéfices de l’IRM et de l’imagerie optique, à savoir une bonne résolution et une haute sensibilité. Afin de gagner encore plus en sensibilité, une nouvelle technique dérivée de l’IRM, appelée « CEST » pour transfert de saturation par échange chimique est née. L’objet de cette thèse est d’apporter la preuve de concept de sondes bimodales pour la détection d’espèces réactive de l’oxygène par des techniques d’imagerie magnétique et d’imagerie optique.Pour cela, des nouvelles familles de complexes de lanthanides portant un ligand radicalaire ou pro-radicalaire ont été synthétisés chimiquement et ont été étudiés par différentes techniques spectroscopiques, électrochimiques. Ces analyses ont permis de valider la preuve de concept par la création de sonde bimodale montrant une altération du signal en fonction de l’état rédox du ligand.

International audience; Solvothermal reactions between hexanuclear complexes with the general chemical formula [Ln(6)(μ(6)-O)(μ(3)-OH)(8)(NO(3))(6)(H(2)O)(12)]·2NO(3)·2H(2)O and 2-bromobenzoic acid (2-bbH) lead to a series of isostructural one-dimensional coordination polymers with the general chemical formula [Ln(2)(2-bb)(6)](∞) with Ln = Sm, Eu, Tb, Dy, and Y. These coordination polymers crystallize in the orthorhombic space group Fdd2 (No. 43) with the following cell parameters: a = 29.810(3) Å, b = 51.185(6) Å, c = 11.7913(14) Å, V = 17992(4) Å(3), and Z = 16. The europium- and terbium-based derivatives show sizable luminescence intensities under UV excitation. Isostructural heterolanthanide coordination polymers have also been prepared. Their luminescent properties suggest that during the synthetic process the starting hexanuclear complexes are destroyed but strongly influence the distribution of the different lanthanide ions over the metallic sites of the crystal structure. Indeed, it is possible to prepare heterolanthanide coordination polymers in which lanthanide-ion segregation is controlled.

Lanthanides complexes are indispensable in fields related to medicine and biology. Their success lies in the great number of unpaired electrons (4f7 configuration of the Gd3+ ion) that makes them ideal contrasts agents for magnetic resonance imaging. On the other hand their narrow emission bands and long lifetime of their excited state provide them unique luminescence properties. The aqueous solution chemistry of the lanthanides is dominated by the (+III) oxidation state under oxygenated atmosphere. This severely limits their use as redox probes, and not surprisingly very few redox-switches employing lanthanide ions were reported until 2010. A very promising approach based on redox-reactive and redox non-innocent ligands has recently emerged in the literature, which overcomes this limitation and expands the application of lanthanides to redox monitoring. Herein the ligand acts as a redox-sensor by either changing its oxidation state or reacting with reactive oxygen (or nitrogen) species (ROS/RNS). Its response induces changes in the environment of the lanthanide ion, which acts as a reporter of the redox status. The detection is based on a modification of the magnetic or optical properties of the complexes, with detection by conventional spectroscopic techniques. We summarize in this review article the recent advances in this burgeoning field, with special emphasis on the detection of biological relevant ROS, RNS and redox status.

The podand-type ligand L, based on a tertiary amine substituted by three pyridyl-6-phosphonic acid functions, forms hydrated complexes with Ln3+ cations. The luminescence properties of the YbL complex were studied in D2O as a function of the pD and temperature. In basic conditions, increases in the luminescence quantum yield and the excited state lifetime of the Yb centered emission associated with the 2F5/2 → 2F7/2 transition were observed and attributed to a change in the hydration number from two water molecules in the first coordination sphere of Yb at acidic pH to a single one in basic conditions. Upon the addition of TbCl3 salts to a solution containing the YbL complex in D2O, heteropolynuclear Yb/Tb species formed, and excitation of the Yb at 980 nm resulted in the observation of the typical visible emission of Tb as a result of a cooperative upconversion (UC) photosensitization process. The UC was further evidenced by the quadratic dependence of the UC emission as a function of the laser power density.

International audience; Electrospray ionization mass spectrometry (ESIMS) is traditionally used to analyse organic molecules, but can also be used to carry out elemental speciation studies. The challenge is here to determine the isotopic composition of elements contained in chemical species by this technique, in addition to their quantification and structural characterisation. In the present work, we determined by ESIMS the isotope ratios of samarium (Sm) and neodymium (Nd) involved in complexes containing polyaminocarbolylic acids, namely EDTA and DTPA. To this end, we developed a user-friendly deconvolution method to remove the ligand isotopic contributions from the abundance ratios measured in the ESI mass spectra of the complexes, and thus obtaining the isotopic composition of the free lanthanides. By applying the deconvolution method to EDTA complexes containing natural and enriched samarium, we obtained the $^{nat}$Sm and the $^{147-149}$Sm isotopic composition directly from the mass spectra of the chemical species recorded by commercial ESI mass spectrometers, equipped with a triple quadrupole analyser (QqQ) or a linear ion trap (LIT). The isotopic composition of $^{nat}$Sm and $^{147-149}$Sm were determined with a trueness better than 3.5% and 2% by ESI-QqQ-MS and better than 1% and 2% by ESI-LIT-MS, with a repeatability globally better than 3% at k=2, for isotopes of relative abundances greater than 1% in samples. This method was successfully applied to determine $^{nat}$Nd and $^{nat}$Sm isotopic compositions from $^{nat}$Nd-EDTA, $^{nat}$Sm-DTPA and $^{nat}$Nd-DTPA mass spectra.

EuIII, TbIII, GdIII and YbIII complexes of the nonadentate bispidine derivative L2 (bispidine=3,7‐diazabicyclo[3.3.1]nonane) were successfully synthesized and their emission properties studied. The X‐ray crystallography reveals full encapsulation by the nonadentate ligand L2 that enforces to all LnIII cations a common highly symmetrical capped square antiprismatic (CSAPR) coordination geometry (pseudo C4v symmetry). The well‐resolved identical emission spectra in solid state and in solution confirm equal structures in both media. As therefore expected, this results in long‐lived excited states and high emission quantum yields ([EuIIIL2]+, H2O, 298 K, τ=1.51 ms, ϕ=0.35; [TbIIIL2]+, H2O, 298 K, τ=1.95 ms, ϕ=0.68). Together with the very high kinetic and thermodynamic stabilities, these complexes are a possible basis for interesting biological probes., EuIII, TbIII, GdIII and YbIII complexes of a nonadentate bispidine derivative were successfully synthesized and their emission properties studied. The X‐ray crystallography reveals full encapsulation by the nonadentate ligand, and the identical emission spectra in the solid state and in solution confirm equal structures in both media. As therefore expected, this results in long‐lived excited states and high emission quantum yields, making these complexes a possible basis for interesting biological probes.

X-rays emitted by synchrotrons are great for studying the atomic structure of materials due to their penetrative nature, as well as their sensitivity to the local and electronic structures of the selected element. It is significantly important for f-elements, precisely actinides since synchrotron-based methods are non-distractive. Actinides such as uranium and plutonium are essential due to their use as a nuclear fuel in commercial nuclear reactors worldwide. Therefore the release of uranium, plutonium and the products of their fission in the environment is of significant concern. The chemical complexity of these elements as well as low concentrations in the samples and/or high radioactivity demand advanced physical methods to reveal fundamental and complicated properties of f-elements, which are needed to predict long-term release from underground repositories of nuclear waste and contaminated sites. In this PhD thesis, the application of various synchrotron-based methods, especially high energy resolution X-ray spectroscopy, on systems containing f-elements is shown.The first part is devoted to synchrotron physics. Beamline setup is discussed in detail using the example of the Rossendorf Beamline II (ROBL-II) at ESRF. General information about the beamline as well as peculiarities associated with the study of radioactive materials are explained in details. Hutch arrangement and full descriptions of experimental stations including experimental equipment are covered.The second part is dedicated to a detailed description of various synchrotron methods such as X-ray diffraction, X-ray absorption near edge structure (XANES) spectroscopy, high energy resolution fluorescence detection (HERFD) XANES, extended X-ray absorption fine structure (EXAFS) spectroscopy and high-energy X-ray scattering (HEXS). The theoretical basis for these methods and their underlying fundamental physics principles are considered. Special attention is given to the HERFD method for this study. The experimental setup used in each method and the most important characteristics are described. All methods will be applied to actinide systems, and a real application of each method will be presented.In particular, the formation processes of MeO2 (Me = Ce, Th, U, Pu) nanoparticles (NPs) and their characterization are discussed. The following parameters of the synthesis are varied: initial oxidation state of the element in which it is taken for the experiment, its concentration, pH, temperature. The structural stability of NPs in terms of time, as well as redox transformation, and thermal sensitivity are also investigated. Pu containing NPs obtained from plutonium solutions of different oxidation states and at various pH are probed for their structural and electronic properties. The presence of oxidation state impurities is investigated. The intermediate phase of Pu(V) in the course of the PuO2 NPs synthesis is described, local structure and the oxidation state of this compound are examined. Besides PuO2 NPs, their analogs – UO2, CeO2 and ThO2 – have been investigated, the results are compared to PuO2. The most important peculiarities for each system have been highlighted. The formation of UO2 NPs under inert conditions is observed, and their oxidation after time under an X-ray beam is remarked. It is found that the properties of CeO2 NPs are affected by their size and their surface is modified by drying at different temperatures. The formation of ThO2 NPs is studied, nanoparticle size was extracted from the HEXS data. HEXS data are fitted by semi-empirical methods and fits based on real NP structures and reveal the presence of small and medium NPs depending on the synthesis conditions. The size effect of ThO2 NPs is also determined., Les rayons X dégagés par les synchrotrons sont utiles dans l’étude de la structure atomique des matériaux de par leur sensibilité aux structures locales et électroniques d’un élément donné. Ces caractéristiques sont particulièrement significatives dans le cas des éléments du bloc f, notamment les actinides puisque les méthodes basées sur le synchrotron ne sont pas distractives. Les actinides comme l’uranium et le plutonium sont essentiels parce qu’ils sont utilisés comme combustible dans des réacteurs nucléaires commerciaux dans le monde entier. Donc, le rejet d’uranium, plutonium et de leurs produits de fission dans l’environnement pose un problème important. La complexité chimique des ces éléments ainsi que leur concentration minimale dans les échantillons et/ou radio-activité forte exigent les méthodes physiques avancées pour révéler les propriétés fondementale et complexes des éléments du bloc-f, dont la compréhension est nécessaire nécessaire afin de pouvoir prédire le rejet à long-terme des profonds dépôts souterrains de déchets nucléaires et des sites contaminés. Dans cette thèse est montrée l’utilisation de différentes méthodes propres au synchrotron, notamment la spectroscopie de la haute résolution de l'énergie par les rayons X sur des systèmes comportant des éléments du bloc f.La première partie de cette thèse est consacrée à la physique pratiquée au synchrotron. L’installation de la ligne est décrite en détails en prenant pour exemple la Rossendorf Beamline (ROBL-II) à l’ESRF. Les informations générales sur la beamline ainsi que les particularités associées avec l’étude des matériaux radioactifs sont mentionnées. La disposition de hutch et la description complète des stations d'expérimentation ainsi que leurs équipements sont abordés.La deuxième partie est dédiée à la description de méthodes synchrotron variées, comme la cristallographie aux rayons X, la spectroscopie de structure près du front d'absorption de rayons X (XANES), détection de fluorescence à haute résolution d’énergie (HERFD) XANES, la spectroscopie EXAFS (EXAFS) et la diffusion de rayons X à haute énergie (HEXS). Le fondement théorique de ces méthodes et sous-jacent principes de la physique fondamentale sont considérés. La méthode HERFD fait l’objet d’une attention particulière en tant que méthode principale de cette thèse. La configuration expérimentale utilisée dans chaque méthode et les caractéristiques les plus importantes sont décrites. Toutes les méthodes seront appliquées aux systèmes des actinides. L'application de chaque méthode à des cas scientifiques réels sera présentée.Les procédures de formation de nanoparticules (NPs) MeO2 (Me = Ce, Th, U, Pu) et leurs caractéristiques sont traités. Les paramètres suivants de la synthèse sont variés: l’état d’oxydation du précurseur, sa concentration, pH et la température. La stabilité des NPs en termes de temps ainsi que l’oxydation et la sensibilité thermique sont également analysés. Pu NPs reçues de précurseurs différents de plutonium de pH varié, leurs caractéristiques structurelles et électroniques sont sondées. La présence d’ impuretés de l’état d’oxydation est analysée. Outre les NPs PuO2, leurs analogues – UO2, CeO2 et ThO2 – ont été étudiés, les résultats sont comparés à PuO2. Les particularités les plus importantes de chaque système ont été mises en évidence. La formation des NPs de UO2 sous les conditions inertes est observée. On a découvert que les NPs de CeO2 sont affectées par leur taille et que leur surface est modifiée par le séchage à différentes températures. La formation de NPs de ThO2 sont analysés, la taille des nanoparticules a été extraite des données HEXS. Les données HEXS sont adaptées par des méthodes semi-empiriques et des ajustements basés sur des structures réelles de NP et révèlent la présence de petites et moyennes NP en fonction des conditions de synthèse. L’effet de taille des NPs de ThO2 est aussi déterminé.

International audience; In an assisted self-assembly approach starting from the [Mn 6 O 2 (piv) 10 (4-Me-py) 2 (pivH) 2 ] cluster a family of Mn Ln compounds (Ln = Pr Yb) was synthesised. The reaction of [Mn 6 O 2 (piv) 10 (4-Me-py) 2 (pivH) 2 ] (1) with N-methyldiethanolamine (mdeaH 2) and Ln(NO 3) 3 • 6H 2 O in MeCN generally yields two main structure types: for Ln = Tb Yb a previously reported Mn 5 Ln 4 motif is obtained, whereas for Ln = Pr Eu a series of Mn 7 Ln 3 clusters is obtained. Within this series the Gd III analogue represents a special case because it shows both structural types as well as a third Mn 2 Ln 2 inverse butterfly motif. Variation in reaction conditions allows access to different structure types across the whole series. This prompts further studies into the reaction mechanism of this cluster assisted self-assembly approach. For the Mn 7 Ln 3 analogues reported here variable-temperature magnetic susceptibility measurements suggest that antiferromagnetic interactions between the spin carriers are dominant. Compounds incorporating Ln = Nd III (2), Sm III (3) and Gd III (5) display SMM behaviour. The slow relaxation of the magnetisation for these compounds was confirmed by ac measurements above 1.8 K.

The reactions between the bis(1,10-phenantro[5,6-b])tetrathiafulvalene triad (L) and the metallo-precursors Yb(hfac)3(H2O)2 (hfac− = 1,1,1,5,5,5-hexafluoroacetylacetonato anion) and Dy(facam)3 (facam− = 3-trifluoro-acetyl-(+)-camphorato anion) lead to the formation of two dinuclear complexes of formula [Yb2(hfac)6(L)]·2(C7H16) ((1)·2(C7H16)) and [Dy2((+)facam)6(L)]·2(C6H14) ((2)·2(C6H14)). The X-ray structures reveal that the L triad bridges two terminal Yb(hfac)3 or Dy(facam)3 units. (1)·2(C7H16) behaved as a near infrared YbIII centered emitter and a field-induced Single-Molecule Magnet (SMM) while (2)·2(C6H14) displayed SMM behavior in both zero- and in-dc field. The magnetization mainly relaxes through a Raman process for both complexes under an optimal applied magnetic field.

International audience; This article highlights the most representative results on the use of coordination compounds in polymerization reactions, since the version of the Comprehensive Coordination Chemistry II by Gibson and Marshall (2003). Noteworthy developments of more efficient catalysts and related significant advancements in coordination polymerization of olefins, radical polymerization, lactide and related cyclic esters polymerization and CO2/epoxides polymerization are discussed therein.

International audience; Molecular luminescent switches form a unique and fascinating class of compounds whose luminescence response can be toggled with chemical or physical stimuli. Switchable near-infrared (NIR) emitters are of major interest since they are compatible with in vivo imaging and have potential for advanced materials such as security tags. Of particular interest are the NIR emitting lanthanides, which feature narrow, sharp and intense emission lines originating from the f-f Laporte forbidden transitions. Although, these "fingerprints" are in general rather insensitive to surrounding media, they can be manipulated thanks to a proper engineering of the complex first or second coordination spheres. The resulting switching systems may thus find usefulness in various application fields. In this review, we selected representative examples of switchable lanthanide NIR emitters based on the most relevant stimuli, such as chemical, environmental, thermal, electrochemical and photochemical inputs.

The use of supported catalysis is of great interest in the present world from both an economic/industrial and environmental point of view. The heterogenization of homogeneous catalysts combines the advantages of homogeneous (high activity and selectivity) and heterogeneous (easy separation of the products at the end of the reaction) catalysis. One of the conditions for this kind of catalysis is a precise knowledge of the interaction between the catalyst and the support. Concerning lanthanide-based catalytic systems, while the use of a silica support has been widely described in the literature, very few studies have been carried out using other supports. In this thesis, therefore, we focused on other supports such as graphene and hexagonal boron nitride (h-BN) trying to understand, by a DFT theoretical study, the influence of the grafting mode and the type of support on the catalytic activity and the stereoselectivity of the different supported catalysts. After a general introduction on the surface organometallic chemistry (SOMC), the first chapter describes the use of lanthanide complexes in the SOMC and their use in catalysis. This is followed by a description of the DFT method used in this work. In the following chapter, we then look at the grafting reaction of the [La(N(SiMe3)2)3] complex on graphene surfaces functionalized by -OH and -COOH groups (gOH and gOOH). These systems are more Lewis acidic than their silica grafted analogues and show interesting catalytic activities in various polymerisation reactions such as the homo-polymerisation of ethylene, butadiene, styrene, beta-butyrolactone (BBL) and methyl methacrylate (MMA) as well as the co-polymerisation of ethylene/butadiene and ethylene/styrene. In Chapter 4, we then study the grafting reaction of the complex [La(N(SiMe3)2)3] on a modified BN surface (BNO-OH) which is characterized by a B-O-B defect and a B-OH function. Like the graphene-grafted systems, also these BN-grafted complexes show a higher Lewis acidity than their silica-grafted counterparts, resulting catalytically active in the homo-polymerisation of ethylene and butadiene. The fifth chapter, finally, deals with the propene polymerisation reaction catalysed by the same graphene and h-BN systems described above. The aim of this chapter is to compare the catalytic activity of the different complexes examined and to understand the role played by the support (BNO-OH and gOH) in a challenging reaction for the polymer industry.KeywordsDFT – SOMC – d/f metals – grafting – polymerisation – lanthanides – supported catalysis; L’utilisation de catalyseurs supportés présente un grand intérêt dans le monde actuel aussi bien d’un point de vue économique/industriel que d’un point de vue environnemental. L’hétérogénéisation des catalyseurs homogènes permet de combiner les avantages de la catalyse homogène (haute activité et sélectivité) et hétérogène (séparation facile des produits en fin de réaction). Un des prérequis pour ce type de catalyse est la connaissance précise de l’interaction entre le catalyseur et le support. En ce qui concerne les systèmes catalytiques à base de lanthanides, si l’utilisation d’une surface de silice en tant que support a été largement décrite dans la littérature, très peu d’études ont été réalisées en employant d’autres supports. Dans cette thèse nous nous sommes donc intéressés à d’autres supports tels que le graphène et le nitrure de bore hexagonal (h-BN) et nous avons essayé de comprendre, par une étude théorique au niveau DFT, l’influence du mode de greffage et du type de support sur l’activité catalytique et la stéréosélectivité des différents catalyseurs supportés. Après une introduction générale sur la chimie organométallique de surface (SOMC), le premier chapitre décrit l’utilisation des complexes de lanthanides dans la SOMC et leur utilisation dans la catalyse. Cette première partie est suivie d’une description de la méthode DFT employée dans ce travail. Nous nous sommes ensuite intéressés, dans le chapitre suivant, à la réaction de greffage du complexe [La(N(SiMe3)2)3] sur des surfaces de graphène fonctionnalisées par des groupements -OH et -COOH (gOH et gOOH). Ces systèmes résultent plus acides de Lewis que leurs homologues greffés sur silice et montrent une activité catalytique intéressante dans différentes réactions de polymérisation telles que l’homo-polymérisation de l’éthylène, du butadiène, du styrène, de la bêta-butyrrolactone (BBL) et du méthacrylate de méthyle (MMA) ainsi que la co-polymérisation éthylène/butadiène et éthylène/styrène. Dans le chapitre 4, nous avons ensuite étudié la réaction de greffage du complexe [La(N(SiMe3)2)3] sur une surface modifiée de BN (BNO-OH) qui se caractérise par un défaut B-O-B et une fonction B-OH. Comme les systèmes greffés sur graphène, aussi ces complexes greffés sur BN montrent une acidité de Lewis plus importante que leurs homologues greffés sur silice, en se montrant catalytiquement actifs dans l’homo-polymérisation de l’éthylène et du butadiène. Le cinquième chapitre, enfin, porte sur la réaction de polymérisation du propène catalysée par les mêmes systèmes greffés sur graphène et sur BN décrits auparavant. Le but de ce chapitre est de comparer l’activité catalytique des différents complexes examinés et de comprendre le rôle joué par le support (BNO-OH et gOH) dans une réaction ayant des enjeux importants pour l’industrie des polymères.Mots-clefsDFT – SOMC – métaux d/f – greffage – polymérisation – lanthanides - catalyse supportée

The work reported in this manuscript deals with the synthesis of phosphonic monomers and polymers, together with the characterization of their complexing properties for selected lanthanides (Ln) and actinides (Ac). The poly(diethyl-6-(acrylamido) hexylcarbamoylmethylphosphonate) (P(CPAAm6C)) and its mono-hydrolysed derivative mhP(CPAAm6C), which contained carbamoylmethylphosphonate groups, were first evaluated for the sorption of gadolinium (Gd(III)) and thorium (Th(IV)), using analytical and calorimetric (ITC) tools. Then, a new monomer oxymethylphosphonate (DiAPC1) was synthesized and polymerized. Polymers before and after hydrolysis, poly((acryloyloxymethyl) phosphonic acid) (hP(APC1)), were evaluated with cerium (Ce(III)) and neodymium (Nd(III)). Finally, another monomer containing acrylamide polymerizable group and phosphonate, named diethyl-2-(acrylamido)ethylphosphonate (DAAmEP), was used to obtain P(DAAmEP) and then hydrolysed leading to hP(DAAMEP). Both polymers were finally evaluated with gadolinium (Gd(III)), cerium (Ce(III)), neodymium (Nd(III)), and thorium (Th(IV))., Les travaux de cette thèse concernent la synthèse de monomères et de polymères phosphorés et la caractérisation de leurs propriétés complexantes envers des lanthanides (Ln) et des actinides (Ac) (représentant des éléments radioactifs). Le polymère poly(diéthyl-6-(acrylamido) hexylcarbamoylmethylphosphonate) (P(CPAAm6C)) et son dérivé mono-hydrolysé mhP(CPAAm6C), contenant des groupes carbamoylméthylphosphonate, ont été évalués pour leur sorption de gadolinium (Gd(III)) et de thorium (Th(IV)), par dosage en solution et par calorimétrie de titrage pour déterminer les constantes de sorption. Puis un nouveau monomère de type oxymethylphosphonate (DiAPC1) a été synthétisé et polymérisé. Les polymères avant et après hydrolyse, nommé poly((acryloyloxymethyl) acide phosphonique) (hP(APC1)) ont été évalués pour leurs interactions avec le cérium (Ce(III)) et le néodyme (Nd(III)). Enfin un autre monomère contenant une fonction polymérisable de type acrylamide et un groupement phosphonate, nommé diéthyl-2-(acrylamido)éthylphosphonate (DAAmEP), a été utilisé afin d’obtenir le polymère P(DAAmEP) correspondant. Il a ensuite été hydrolysé afin d’aboutir à la forme acide phosphonique (hP(DAAMEP)). Les deux polymères ont été testés pour leur extraction de gadolinium (Gd(III)), du cérium (Ce(III)), du néodyme (Nd(III)) et du thorium (Th(IV)).

Zinc and copper are essential cations involved in numerous biological processes, and variations in their concentrations can cause diseases such as neurodegenerative diseases, diabetes and cancers. Hence, detection and quantification of these cations are of utmost importance for the early diagnosis of disease. Magnetic resonance imaging (MRI) responsive contrast agents (mainly Lanthanide(+III) complexes), relying on a change in the state of the MRI active part upon interaction with the cation of interest, e.g., switch ON/OFF or vice versa, have been successfully utilized to detect Zn2+ and are now being developed to detect Cu2+. These paramagnetic probes mainly exploit the relaxation-based properties (T1-based contrast agents), but also the paramagnetic induced hyperfine shift properties (paraCEST and parashift probes) of the contrast agents. The challenges encountered going from Zn2+ to Cu2+ detection will be stressed and discussed herein, mainly involving the selectivity of the probes for the cation to detect and their responsivity at physiologically relevant concentrations. Depending on the response mechanism, the use of fast-field cycling MRI seems promising to increase the detection field while keeping a good response. In vivo applications of cation responsive MRI probes are only in their infancy and the recent developments will be described, along with the associated quantification problems. In the case of relaxation agents, the presence of another method of local quantification, e.g., synchrotron X-Ray fluorescence, single-photon emission computed tomography (SPECT) or positron emission tomography (PET) techniques, or 19F MRI is required, each of which has its own advantages and disadvantages.

The isotopic and elemental compositions of nuclear samples were determined with the hyphenation of capillary electrophoresis (CE) to multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). A single step separation method by CE of the key elements of a spent nuclear fuel sample was developed. This method was optimized using an inactive sample by hyphenation with a quadrupole ICP-MS (Q-ICP-MS). It was then applied to a real spent nuclear fuel sample by hyphynation with a nuclearised Q-ICP-MS. Uranium, plutonium, minor actinides (Am, Cm) and fission products (Nd, Sm, Eu, Gd) were separated. The CE-MC-ICP-MS hyphenation allowed the determination of isotope ratio for these elements (except uranium) with uncertainties of a few per-mil and with sample quantities of a few hundreds of pg. Liquid waste production was in the µL range. Those values were notably inferior to the ones obtained with a routinely used offline protocol which were respectively in the µg and the hundreds of mL range. The age of a uranium sample was determined by CE-MC-ICP-MS with the 234U/230Th radiochronometer. The 230Th concentration in the sample was determined with the isotope dilution method using a 232Th spike. A preconcentration method associated with detection by a secondary electron multiplier allowed to measure the few hundreds of fg of 230Th present in the sample. The developments carried out throughout this PhD will be applied and adapted to analytical microsystems.; La composition isotopique et élémentaire d'échantillons nucléaires a été déterminée par couplage de l'électrophorèse capillaire (CE) à la spectrométrie de masse à source plasma et à multicollection (MC-ICP-MS). Une méthode de séparation des éléments d'intérêt d'un échantillon de combustible nucléaire usé en une étape de CE a été développée. Cette méthode a été optimisée sur un échantillon inactif par couplage avec un ICP-MS quadripolaire (Q-ICP-MS). Elle a ensuite été appliquée à un échantillon réel de combustible nucléaire usé, par couplage avec un Q-ICP-MS nucléarisé. L'uranium, le plutonium, les actinides mineurs (Am, Cm) et les produits de fission (Nd, Sm, Eu, Gd) ont été séparés. Le couplage CE-MC-ICP-MS a permis la détermination des rapports isotopiques des éléments précités (à l'exception de l'U) avec des incertitudes de l'ordre du pour-mille et des quantités d'échantillons de l'ordre de la centaine de pg. Le volume des effluents est de l'ordre du µL. Ces valeurs sont nettement inférieures à celles mises en jeu par le protocole utilisé en routine dans le laboratoire qui sont respectivement de l'ordre du µg et de la centaine de mL. Un échantillon d'uranium a été daté avec le radiochronomètre 234U/230Th par couplage CE-MC-ICP-MS. La concentration en 230Th de l'échantillon a été déterminée par la méthode de la dilution isotopique avec un traceur de 232Th. Le développement d'une méthode de pré-concentration par complexation associée à une détection avec un multiplicateur d'électrons secondaires a permis la mesure du 230Th présent à hauteur de quelques centaines de fg. Les développements effectués durant cette thèse seront transposés sur des microsystèmes analytiques.

The isotopic and elemental compositions of nuclear samples were determined with the hyphenation of capillary electrophoresis (CE) to multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). A single step separation method by CE of the key elements of a spent nuclear fuel sample was developed. This method was optimized using an inactive sample by hyphenation with a quadrupole ICP-MS (Q-ICP-MS). It was then applied to a real spent nuclear fuel sample by hyphynation with a nuclearised Q-ICP-MS. Uranium, plutonium, minor actinides (Am, Cm) and fission products (Nd, Sm, Eu, Gd) were separated. The CE-MC-ICP-MS hyphenation allowed the determination of isotope ratio for these elements (except uranium) with uncertainties of a few per-mil and with sample quantities of a few hundreds of pg. Liquid waste production was in the µL range. Those values were notably inferior to the ones obtained with a routinely used offline protocol which were respectively in the µg and the hundreds of mL range. The age of a uranium sample was determined by CE-MC-ICP-MS with the 234U/230Th radiochronometer. The 230Th concentration in the sample was determined with the isotope dilution method using a 232Th spike. A preconcentration method associated with detection by a secondary electron multiplier allowed to measure the few hundreds of fg of 230Th present in the sample. The developments carried out throughout this PhD will be applied and adapted to analytical microsystems.; La composition isotopique et élémentaire d'échantillons nucléaires a été déterminée par couplage de l'électrophorèse capillaire (CE) à la spectrométrie de masse à source plasma et à multicollection (MC-ICP-MS). Une méthode de séparation des éléments d'intérêt d'un échantillon de combustible nucléaire usé en une étape de CE a été développée. Cette méthode a été optimisée sur un échantillon inactif par couplage avec un ICP-MS quadripolaire (Q-ICP-MS). Elle a ensuite été appliquée à un échantillon réel de combustible nucléaire usé, par couplage avec un Q-ICP-MS nucléarisé. L'uranium, le plutonium, les actinides mineurs (Am, Cm) et les produits de fission (Nd, Sm, Eu, Gd) ont été séparés. Le couplage CE-MC-ICP-MS a permis la détermination des rapports isotopiques des éléments précités (à l'exception de l'U) avec des incertitudes de l'ordre du pour-mille et des quantités d'échantillons de l'ordre de la centaine de pg. Le volume des effluents est de l'ordre du µL. Ces valeurs sont nettement inférieures à celles mises en jeu par le protocole utilisé en routine dans le laboratoire qui sont respectivement de l'ordre du µg et de la centaine de mL. Un échantillon d'uranium a été daté avec le radiochronomètre 234U/230Th par couplage CE-MC-ICP-MS. La concentration en 230Th de l'échantillon a été déterminée par la méthode de la dilution isotopique avec un traceur de 232Th. Le développement d'une méthode de pré-concentration par complexation associée à une détection avec un multiplicateur d'électrons secondaires a permis la mesure du 230Th présent à hauteur de quelques centaines de fg. Les développements effectués durant cette thèse seront transposés sur des microsystèmes analytiques.

Herein, the design, synthesis, and characterization of a phenhomazine ligand are described. The ligand has six pendant acetate arms designed for the combined coordination of copper(II) and lanthanide(III) ions, with the perspective of developing a “turn-off” copper sensor. The key step for the ligand preparation was the one-step endomethylene bridge fission of a diamino Tröger's base with a concomitant alkylation. Fluorescence and absorption spectroscopies as well as nuclear magnetic resonance (NMR) experiments were performed to analyze and understand the coordination properties of the ligand. Transition metal coordination was driven by the synergistic effect of the free nitrogen atoms of the diazocinic core and the two central acetate arms attached to those nitrogen atoms, whereas lanthanide coordination is performed by the external acetate arms, presumably forming a self-assembled 2:2 metallosupramolecular structure. The terbium complex shows the typical green emission with narrow bands and long luminescence lifetimes. The luminescence quenching produced by the presence of copper(II) ions was analyzed. This work sets, therefore, a starting point for the development of a phenhomazine-based “turn-off” copper(II) sensor. Fil: Trupp, Leandro Julián. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Centre National de la Recherche Scientifique; Francia Fil: Bruttomesso, Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina Fil: Eliseeva, Svetlana V.. Centre National de la Recherche Scientifique; Francia Fil: Petoud, Stéphane. Centre National de la Recherche Scientifique; Francia Fil: Ramírez, Fernando Javier. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina Fil: Barja, Beatriz Carmen. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina

Herein, the synthesis and characterization of the first family of multipodal ligands with a Tröger's base framework designed for the preparation of luminescent lanthanide(III) complexes are reported. Eight ligands were designed and synthesized using different strategies, including alkylation reactions, amide couplings, and Ugi multicomponent reactions. All the ligands bear carboxylate groups for the coordination of the lanthanide(III) ions, with the lanthanide(III)-sensitizing units consisting of the Tröger's base framework itself or attached benzamides. Upon irradiation of the chromophoric ligands, green terbium(III) emission was efficiently generated, whereas europium(III) emission was negligible. The geometry and substitution pattern of the ligands allow control of the stoichiometry of the species formed and the TbIII luminescence sensitization efficiency, showing that para-substitution patterns are more efficient than meta substitution for the formation of coordination compounds with lower TbIII/ligand ratio. We propose that the species formed are self-assembled 2:2 or 2:4 metallosupramolecular structures. Fil: Trupp, Leandro Julián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Centre National de la Recherche Scientifique; Francia Fil: Bruttomesso, Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina Fil: Varde, Mariana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina Fil: Eliseeva, Svetlana. Centre National de la Recherche Scientifique; Francia Fil: Ramirez, Javier Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina Fil: Petoud, Stephane. Centre National de la Recherche Scientifique; Francia Fil: Barja, Beatriz Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina

International audience; Reaction of the tungsto-antimonate [Sb 8 W 36 O 132 ] 24-polyoxometalate with late trivalent lanthanide cations (from Gd to Lu) gives rise to the formation of eight isostructural molecular compounds [{Sb 3 ( 3-O) 2 Ln(H 2 O)Ln(H 2 O) 2 (SbW 10 O 37)(SbW 8 O 31)} 2 ] 22-(Ln = Gd III (1), Tb III (2), Dy III (3), Ho III (4), Er III (5), Tm III (6), Yb III (7), Lu III (8)). All compounds were characterized by routine solid-state techniques (IR spectroscopy, TGA, single crystal X-ray diffraction) and, by SAXS measurements in aqueous solutions to assess their stabilities. Luminescent properties of compounds 5 and 7 were also studied.

A new family of five‐coordinate lanthanide single‐molecule magnets (Ln SMMs) [Dy(Mes*O)2(THF)2X] (Mes*=2,4,6‐tri‐tert‐butylphenyl; X=Cl, 1; Br, 2; I, 3) is reported with energy barriers to magnetic reversal >1200 K. The five‐coordinate DyIII ions have distorted square pyramidal geometries, with halide anions on the apex, and two Mes*O ligands mutually trans‐ to each other, and the two THF molecules forming the second trans‐ pair. These geometrical features lead to a large magnetic anisotropy in these complexes along the trans‐Mes*O direction. QTM and Raman relaxation times are enhanced by varying the apex halide from Cl to Br to I, or by dilution in a diamagnetic yttrium analogue., Halide influence: A new family of five‐coordinate lanthanide‐based single‐molecule magnets, [Dy(Mes*O)2(THF)2X] (Mes*=2,4,6‐tri‐tert‐butylphenyl), (X=Cl, Br, I) is reported. While the influence of the different halides on the quantum tunnelling of magnetization and Raman processes is clearly established, the Orbach relaxation is independent of the halide substitution.

The biological role of REEs has long been underestimated, and research has mainly focused on methanotrophic and methylotrophic bacteria. We have recently demonstrated that P. putida, a plant growth-promoting bacterium that thrives in the rhizosphere of various food crops, possesses a REE-dependent alcohol dehydrogenase (PedH), but knowledge about REE-specific effects on physiological traits in nonmethylotrophic bacteria is still scarce. This study demonstrates that the cellular response of P. putida to lanthanum (La3+) is mostly substrate specific and that La3+ availability highly affects the growth of cells on glycerol. Further, a novel route for glycerol metabolism is identified, which is initiated by PedE and/or PedH activity and provides a growth advantage to this biotechnologically relevant organism by allowing a faster onset of growth. Overall, these findings demonstrate that lanthanides can affect physiological traits in nonmethylotrophic bacteria and might influence their competitiveness in various environmental niches., Ever since the discovery of the first rare earth element (REE)-dependent enzyme, the physiological role of lanthanides has become an emerging field of research due to the environmental implications and biotechnological opportunities. In Pseudomonas putida KT2440, the two pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) PedE and PedH are inversely regulated in response to REE availability. This transcriptional switch is orchestrated by a complex regulatory network that includes the PedR2/PedS2 two-component system and is important for efficient growth on several alcoholic volatiles. To study whether cellular responses beyond the REE switch exist, the differential proteomic responses that occur during growth on various model carbon sources were analyzed. Apart from the Ca2+-dependent enzyme PedE, the differential abundances of most identified proteins were conditional. During growth on glycerol—and concomitant with the proteomic changes—lanthanum (La3+) availability affected different growth parameters, including the onset of logarithmic growth and final optical densities. Studies with mutant strains revealed a novel metabolic route for glycerol utilization, initiated by PedE and/or PedH activity. Upon oxidation to glycerate via glyceraldehyde, phosphorylation by the glycerate kinase GarK most likely yields glycerate-2-phosphate, which is eventually channeled into the central metabolism of the cell. This new route functions in parallel with the main degradation pathway encoded by the glpFKRD operon and provides a growth advantage to the cells by allowing an earlier onset of growth with glycerol as the sole source of carbon and energy.

New tridimensional 4f-3d molecular materials can be obtained through crystal growth in gel medium. A simple, economic, ecologic and environmentally friendly synthesis method that has been used until recently for the growth of mononuclear crystalline molecular materials. During this international joint PhD between Assane Seck Ziguinchor University (Senegal) and Lorraine University (France), it was possible to synthesize several novel crystalline phases of molecular materials. Ten new 4f-3d heteronuclear molecular materials was obtained by slow diffusion in gel medium and structurally characterized by single crystal X-ray diffraction. Eight of them belong to the same family of isostructural compounds [Ln(III)M(II)(3,5-pdc)2(Oxa)0.5(H2O)8]2H2O (Ln = Pr, Nd, Sm, Eu, Gd and M = Cu, Co) and can be described as one-dimensional coordination polymers. Their structure is composed of dinuclear chains sandwiching oxalate ligands and the three-dimensional network is ensured by hydrogen bonds of water molecules assisted by π-π* stacking interactions. The last two are three-dimensional coordination polymers. The one based on Sm3+ and Cu2+ [SmCu(3,5-pdc)2(Oxa)0.5(H2O)6]2H2O is a polymorph to a compound belonging to the family of isostructural compounds. Its structure consists of parallel layers bridged by oxalate ligands to generate a final three-dimensional network. As for the compound based on Dy3+ and Ni2+ [DyNi0.5(3,5-pdc)0.5(Oxa)1.5(H2O)3,5]6,5H2O it is a Metal-Organic Framework (MOFs). Its structure is formed of honeycomb layers constructed with three types of oxalate ligand interconnected by the core ligand pyridine-3,5-dicarboxylate to give rise to a porous three-dimensional structure.; Il est désormais possible, en utilisant la méthode de synthèse par diffusion lente en milieu gel, d’élaborer de nouveaux matériaux moléculaires mixtes 4f-3d tridimensionnels présentant des propriétés physiques et chimiques très intéressantes. La méthode gel est une technique de synthèse simple, économique, écologique et respectueux de l’environnement qui jusque-là n’avait généralement été utilisée que pour la mise au point de matériaux moléculaires mononucléaires. Au cours de cette thèse doctorale en cotutelle entre l’Université Assane Seck de Ziguinchor (Sénégal) et l’Université de Lorraine (France), il a été possible de mettre en évidence plusieurs nouvelles phases cristallines inédites de matériaux moléculaires. Dix nouveaux matériaux moléculaires mixtes 4f-3d ont été synthétisés par voie gel et structuralement caractérisés par diffraction des rayons-X sur monocristal. Huit d’entre eux appartiennent à une même famille de composés isostructuraux [Ln(III)M(II)(3,5-pdc)2(Oxa)0.5(H2O)8]2H2O (Ln = Pr, Nd, Sm, Eu et Gd; et M = Cu et Co) pouvant être décrits comme des polymères de coordination unidimensionnels constitués de chaînes «illimitées» en forme d’échelle. Les deux derniers, quant à eux, sont des polymères de coordination tridimensionnels. Le composé à base du Sm3+ et du Cu2+ [SmCu(3,5-pdc)2(Oxa)0.5(H2O)6]2H2O est un polymorphe à un des composés de la famille isostructurale. Il est constitué de couches parallèles pontées par les ligands oxalates pour engendrer la structure tridimensionnelle finale. Quant au composé à base du Dy3+ et du Ni2+ [DyNi0.5(3,5-pdc)0.5(Oxa)1.5(H2O)3,5]6,5H2O, il s’agit d’un polymère de coordination à charpente ouverte (MOFs). Il est formé de couches en forme de nid d’abeilles construites avec trois types de ligand oxalate interconnectées par le ligand de base pyridine-3,5-dicarboxylate pour donner une structure tridimensionnelle poreuse.

New tridimensional 4f-3d molecular materials can be obtained through crystal growth in gel medium. A simple, economic, ecologic and environmentally friendly synthesis method that has been used until recently for the growth of mononuclear crystalline molecular materials. During this international joint PhD between Assane Seck Ziguinchor University (Senegal) and Lorraine University (France), it was possible to synthesize several novel crystalline phases of molecular materials. Ten new 4f-3d heteronuclear molecular materials was obtained by slow diffusion in gel medium and structurally characterized by single crystal X-ray diffraction. Eight of them belong to the same family of isostructural compounds [Ln(III)M(II)(3,5-pdc)2(Oxa)0.5(H2O)8]2H2O (Ln = Pr, Nd, Sm, Eu, Gd and M = Cu, Co) and can be described as one-dimensional coordination polymers. Their structure is composed of dinuclear chains sandwiching oxalate ligands and the three-dimensional network is ensured by hydrogen bonds of water molecules assisted by π-π* stacking interactions. The last two are three-dimensional coordination polymers. The one based on Sm3+ and Cu2+ [SmCu(3,5-pdc)2(Oxa)0.5(H2O)6]2H2O is a polymorph to a compound belonging to the family of isostructural compounds. Its structure consists of parallel layers bridged by oxalate ligands to generate a final three-dimensional network. As for the compound based on Dy3+ and Ni2+ [DyNi0.5(3,5-pdc)0.5(Oxa)1.5(H2O)3,5]6,5H2O it is a Metal-Organic Framework (MOFs). Its structure is formed of honeycomb layers constructed with three types of oxalate ligand interconnected by the core ligand pyridine-3,5-dicarboxylate to give rise to a porous three-dimensional structure., Il est désormais possible, en utilisant la méthode de synthèse par diffusion lente en milieu gel, d’élaborer de nouveaux matériaux moléculaires mixtes 4f-3d tridimensionnels présentant des propriétés physiques et chimiques très intéressantes. La méthode gel est une technique de synthèse simple, économique, écologique et respectueux de l’environnement qui jusque-là n’avait généralement été utilisée que pour la mise au point de matériaux moléculaires mononucléaires. Au cours de cette thèse doctorale en cotutelle entre l’Université Assane Seck de Ziguinchor (Sénégal) et l’Université de Lorraine (France), il a été possible de mettre en évidence plusieurs nouvelles phases cristallines inédites de matériaux moléculaires. Dix nouveaux matériaux moléculaires mixtes 4f-3d ont été synthétisés par voie gel et structuralement caractérisés par diffraction des rayons-X sur monocristal. Huit d’entre eux appartiennent à une même famille de composés isostructuraux [Ln(III)M(II)(3,5-pdc)2(Oxa)0.5(H2O)8]2H2O (Ln = Pr, Nd, Sm, Eu et Gd; et M = Cu et Co) pouvant être décrits comme des polymères de coordination unidimensionnels constitués de chaînes «illimitées» en forme d’échelle. Les deux derniers, quant à eux, sont des polymères de coordination tridimensionnels. Le composé à base du Sm3+ et du Cu2+ [SmCu(3,5-pdc)2(Oxa)0.5(H2O)6]2H2O est un polymorphe à un des composés de la famille isostructurale. Il est constitué de couches parallèles pontées par les ligands oxalates pour engendrer la structure tridimensionnelle finale. Quant au composé à base du Dy3+ et du Ni2+ [DyNi0.5(3,5-pdc)0.5(Oxa)1.5(H2O)3,5]6,5H2O, il s’agit d’un polymère de coordination à charpente ouverte (MOFs). Il est formé de couches en forme de nid d’abeilles construites avec trois types de ligand oxalate interconnectées par le ligand de base pyridine-3,5-dicarboxylate pour donner une structure tridimensionnelle poreuse.

International audience; We report a detailed study of the thermodynamic stability and dissociation kinetics of lanthanide complexes with two ligands containing a cyclen unit, a methyl group, a picolinate arm, and two acetate pendant arms linked to two nitrogen atoms of the macrocycle in either cis (1,4-H3DO2APA) or trans (1,7-H3DO2APA) positions. The stability constants of the Gd3+ complexes with these two ligands are very similar, with log KGdL values of 16.98 and 16.33 for the complexes of 1,4-H3DO2APA and 1,7-H3DO2APA, respectively. The stability constants of complexes with 1,4-H3DO2APA follow the usual trend, increasing from log KLaL = 15.96 to log KLuL = 19.21. However, the stability of [Ln(1,7-DO2APA)] complexes decreases from log K = 16.33 for Gd3+ to 14.24 for Lu3+. The acid-catalyzed dissociation rates of the Gd3+ complexes differ by a factor of ∼15, with rate constants (k1) of 1.42 and 23.5 M–1 s–1 for [Gd(1,4-DO2APA)] and [Gd(1,7-DO2APA)], respectively. This difference is magnified across the lanthanide series to reach a 5 orders of magnitude higher k1 for [Yb(1,7-DO2APA)] (1475 M–1 s–1) than for [Yb(1,4-DO2APA)] (5.79 × 10–3 M–1 s–1). The acid-catalyzed mechanism involves the protonation of a carboxylate group, followed by a cascade of proton-transfer events that result in the protonation of a nitrogen atom of the cyclen unit. Density functional theory calculations suggest a correlation between the strength of the Ln–Ocarboxylate bonds and the kinetic inertness of the complex, with stronger bonds providing more inert complexes. The 1H NMR resonance of the coordinated water molecule in the [Yb(1,7-DO2APA)] complex at 176 ppm provides a sizable chemical exchange saturation transfer effect thanks to a slow water exchange rate of (15.9 ± 1.6) × 103 s–1.; L'arrangement des atomes donneurs de ligand autour de l'ion lanthanide provoque des différences dramatiques dans les stabilités thermodynamiques et la cinétique de dissociation des complexes de lanthanides, comme le démontre l'étude des complexes avec deux ligands à base de régioisomères du cyclen, contenant un bras picolinate et deux bras acétate soit en position 1,7 ou 1,4 de la structure macrocyclique.

The synthesis of lanthanides other than cerium in the oxidation state +IV has remained a desirable but unmet target until recently, when two examples of Tb-IV with saturated coordination spheres were isolated. Here we report the third example of an isolated molecular complex of terbium(IV), where the supporting siloxide ligands do not saturate the coordination sphere. The fully characterized six-coordinate complex [Tb-IV(OSiPh3)(4)(MeCN)(2)], 2-Tb-Ph, shows high stability and the labile MeCN ligands can be replaced by phosphinoxide ligands. Computational studies suggest that the stability is due to a strong pi(O-Tb) interaction which is stronger than in the previously reported Tb-IV complexes. Cyclic-voltammetry experiments demonstrate that non-binding counterions contribute to the stability of Tb-IV in solution by destabilizing the +III oxidation state, while alkali ions promote Tb-IV/Tb-III electron transfer.

International audience; The tetra-substituted heptadentate cyclen (1,4,7,10-tetraazacyclododecane) based Eu(III)/Tb(III)/Gd(III)-complexes 1.Ln and 2.Ln were developed. 1.Eu/Tb and 2.Eu/Tb were employed in the formation of luminescent self-assembling ternary structures, and we demonstrate that only in the presence of appropriate sensitizing antennae, was the lanthanide-emission of 1.Eu/Tb and 2.Eu/Tb ‘switched on’. 1.Gd/2.Gd were developed as potential MIR contrast agents, and employed in NMRD-measurements, where their relaxivity was investigated, and their (relatively high) r1 values determined. The formation of a self-assembled micelle-type structure was clearly observed for 2.Gd. The functionalised gold nanoparticles 1.Ln-AuNP were also synthesized from 1.Ln. As for the free complexes, the Ln-emission was ‘switched on’ for 1.Eu/Tb-AuNP in the presence of the antennae. NMRD measurements indicated that the relaxivity for the 1.Gd-AuNP systems was very high, with a value of 445 s-1mM-1 (at 400 MHz), demonstrating the cumulative effect of the relatively high number of 1.Gd complexes on the surface of the AuNP.

International audience; We report the synthesis of an original ligand scaffold and the corresponding yttrium(III), europium(III) and ytterbium(III) complexes. All three compounds show reversible photochromism with high photo-conversions. Photoluminescence experiments demonstrate that this design is adapted for both europium and ytterbium emission switching. The OFF/ON luminescence ratio are excellent in the case of europium (4 to 8 %) and still quite good in the case of ytterbium (around 13 %); Nous présentons la synthèse d'un ligand original et ses complexes d'yttrium (III), d'europium (III) et d'ytterbium (III). Les trois composés présentent un photochromisme réversible avec des photo-conversions élevées. Les expériences de photoluminescence démontrent que le conception est adapté tant pour la commutation de l’émission de l'europium et de l'ytterbium. Le rapport de luminescence OFF/ON est excellent dans le cas de l'europium (4 à 8%) et encore assez bon dans le cas de l'ytterbium (environ 13%)

DNA is the carrier of genetic information in living organisms. Targeting and visualizing in vivo a specific DNA sequence is of particular interest for medical diagnosis and biological research. In this purpose, luminescent detection is very attractive because it can be easily observed with simple tools.The aim of this work was to establish the proof of concept of luminescent probes for the sequence-specific detection of double stranded DNA based on lanthanide luminescence, which is attractive for biological applications, and on zinc finger proteins for their DNA binding properties. We focused on the detection of a 12-base pair palindromic DNA using a pair of zinc finger proteins, one bearing a lanthanide(III) complex as a the FRET donor and the other an organic fluorophore as an acceptor.In this purpose, a new family of bioconjugatable lanthanide(III) complexes was developed and zinc finger proteins with various chromophores were synthesized chemically, by combination of solid phase peptide synthesis and assembly of peptidic segments by native chemical ligation. The spectroscopic characterizations of these systems have evidenced the interaction of the probes with the palindromic DNA, thereby validating the proof of concept of luminescence detection of this DNA sequence by a lanthanide-based FRET system., L’ADN est le support de l’information de tout être vivant. La possibilité de pouvoir cibler et visualiser in vivo une séquence spécifique d’ADN et plus particulièrement un gène est un enjeu de taille pour le suivi médical aussi bien que pour la compréhension du vivant. Pour y parvenir, la détection par luminescence est particulièrement attrayante de par sa facilité de visualisation avec des outils simples.L’objet de cette thèse était d’apporter la preuve de concept de sondes luminescentes pour la détection séquence spécifique d’ADN double brin, basées d’une part sur les propriétés de luminescence des lanthanides, particulièrement intéressantes pour la détection en milieu biologique, et d’autre part sur les propriétés de reconnaissance de l’ADN par les protéines à doigts de zinc. Nous nous sommes intéressé au ciblage d’un duplex d’ADN palindromique de 12 paires de bases par un couple de protéines à doigts de zinc intégrant un système FRET, où un complexe de lanthanide(III) sur une protéine joue le rôle de donneur et un fluorophore organique sur l’autre protéine joue celui d’accepteur.Pour cela, une nouvelle famille de complexes de lanthanide(III) bioconjugables a été élaborée et des protéines à doigts de zinc fonctionnalisée par différents chromophores ont été synthétisés chimiquement par synthèse peptidique supportée sur résine et assemblage par ligation chimique native de trois fragments. Les caractérisations spectroscopiques des systèmes développés ont permis de mettre en évidence l’interaction des sondes avec la séquence d’ADN palindromique et de valider la preuve de concept d’une détection de cette séquence par un FRET basé sur des lanthanides.

International audience; Use of 155Gd Mössbauer spectroscopy allows a straightforward characterization of heterodinuclear Ln-Ln′ complexes (LLnLn′ (NO3)3·(H2O)2) with a tripodal ligand L, possessing two different N4O3 and O3O3 coordination sites. Thanks to the isomer shift value, the location of the GdIII ion is confirmed; the Gd atom in the Gd–Ln′ series (Ln′ = Ce, Nd, Eu) occupies the inner N4O3 site with a eight-coordination (N4O3 + O), but on the other hand the Gd atom in the Ln–Gd series (Ln = Dy, Er, Yb) resides in the outer O3O3 site with a ten-coordination (O3O3 + O2 + O2). The smaller isomer shift values for the former indicate that coordination of the basic nitrogen atoms enhances the 6s orbital population. With the help of 151Eu Mössbauer spectroscopy, we demonstrate that the Gd–Eu entity is a genuine heterodinuclear complex, in which the GdIII ion is located in the inner site and the EuIII ion in the outer oxygenated site. This result highlights the feasibility of our synthetic process described earlier to introduce in a heterodinuclear complex two consecutive ions of the periodic table. And the slow paramagnetic relaxation observed in the 166Er Mössbauer spectrum of the Er–Gd complex confirms presence of a magnetic interaction in the genuine Er–Gd complex.

Due to the increasing human activities in the civilian nuclear fields, the actual and potential release of radionuclides into the environment is a matter of concern. The mobility of radio-nuclides depends on several factors such as pH, ionic strength, oxidation state and the presence of organic ligands. In order to guarantee the safety of radioactive waste storage sites and to develop contaminated soil remediation processes, it is necessary to have fundamental data on actinides and natural organic ligands interactions. This study focuses on the interaction between Th(IV), U(IV,VI), Cf(III) and Eu(III) and hydroxamates derivatives, desferrioxamine B, a bacterial siderophore with three hydroxamic functions. The stability constants of complexes are determined as function of acidity and ligand concentration, at fixed ionic strength and temperature, using several techniques and metal concentrations ranging from 10⁻¹⁰ to 10⁻³ M (liquid-liquid extraction coupled with γ-spectrometry, capillary electrophoresis with UV detection, UV-Vis absorption spectrophotometry). The thermodynamic study is supplemented by a structural one using spectroscopic techniques such as Fourier transform infrared spectroscopy and X-ray absorption spectroscopy. Experimental measurements are compared with quantum chemistry calculations (DFT) in order to determine the coordination geometry of the metal ion and the interatomic distances.; L’augmentation des activités humaines dans le domaine nucléaire civil comme militaire est à l’origine d’une dissémination effective ou potentielle de radionucléides dans l’environnement. Leur mobilité dépend de plusieurs facteurs tels que le pH, la force ionique, le degré d’oxydation et la présence de ligands organiques. Afin de garantir la sûreté de sites d’entreposage ou de stockage, de développer des procédés de remédiation de sols contaminés, il est nécessaire de disposer de données fondamentales sur les interactions entre actinides et ligands organiques susceptibles d’être présents dans l’environnement, vecteurs de migration ou de piégeage de ces radioéléments. Dans ce contexte, l’étude s’est axée sur les interactions entre Th(IV), U(IV,VI), Cf(III) and Eu(III) et des dérivés hydroxamates, en particulier, la desferrioxamine B, un sidérophore bactérien comportant trois fonctions hydroxamiques. Les constantes de formation des complexes sont déterminées en fonction de l’acidité et de la concentration de ligand à force ionique et température fixées en mettant en jeu plusieurs techniques expérimentales et des concentrations en élément comprises entre 10⁻¹⁰ et 10⁻³ M (extraction liquide-liquide combinée à une détection par spectrométrie γ, électrophorèse capillaire avec détection UV, spectrophotométrie d’absorption UV-visible). L’approche thermodynamique de cette étude est complétée par une étude structurale à l’aide de techniques spectroscopiques telles que la spectroscopie infrarouge à transformée de Fourier et de la spectroscopie d’absorption des rayons X. Ces mesures expérimentales sont alors confrontées à des calculs théoriques (DFT), afin de déterminer l’arrangement structural du métal et les distances interatomiques.

International audience; This review summarizes the progress in organo-f-element chemistry during the year 2018. A continuing trend for many years, which remained important in 2018, was the synthesis and investigation of reactive trivalent lanthanide mono- and bis(alkyl) or (benzyl) complexes supported by a variety of non-cyclopentadienyl ligands such as amidinates, β-diketiminates or NHC ligands. An important contribution was the synthesis of the homoleptic, solvent-free dibenzyl complexes [Ln(CH2Ph)2]n (Ln = Eu, Sm, Yb) which served as precursors for the synthesis of the first divalent lanthanide imides [(THF)Ln(μ3-NDipp)]4. Lanthanide carbene chemistry has also been of growing interest. Functionalized NHC ligands were employed to unveil new reactivity as demonstrated in the synthesis of homoleptic lanthanide complexes with aryloxide-tethered NHC ligands, Ln(LR)3 (LR = 2-O-3,5-tBu2C6H2(1-C{N(CH)2N(R)}), R = iPr, tBu, Mes), which reacted with CO2 by selective insertion into Ln–C(NHC) bonds. A diverse reactivity towards small unsaturated molecules was observed for phosphino and thiophosphinoyl alkylidene lanthanide complexes as well as for phosphinidene lanthanide complexes. Furthermore, the trinuclear mixed oxo/alkyl complexes L13Ln3(μ2-CH3)3(μ3-CH3)(μ3-O) (with L1 = PhC(NC6H3iPr2-2,6)2; Ln = Sc, Y, Lu, Dy) undergo non-redox oxygen transfer with PhNCS or CS2 despite the presence of reactive Ln-alkyl bonds. The synthesis of pseudo-Grignard reagents PhLnI (Ln = Eu, Yb) was investigated and their synthetic potential in organometallic chemistry demonstrated. The first lanthanide-cyclobutadienyl complexes were obtained as anionic “tuck-in” complexes [M{η4-C4(SiMe3)4}{η4-C4(SiMe3)3-κ-(CH2SiMe2)}]2− (Ln = Y, Dy), showing square-shaped cyclobutadienyl ligands. Further progress has been made in the understanding of “new” divalent lanthanide chemistry, especially the influence of the ligand size. The small CpMe ligand formed highly reactive complexes, e.g. [K(crypt)][Y(CpMe)3], with the larger lanthanides, which reacted with the solvent to give unprecedented reductive THF-ring opening. However, with smaller lanthanides the complexes [(18-crown-6)K(μ-CpMe)K(18-crown-6)][CpMe3Ln] (Ln = Tb, Ho), displaying an inverse sandwich as counter-cation, could be isolated. The reactivity of the highly bulky complex SmCpAr-Et2 (CpAr-Et = C5(4-EtC6H4)5) towards a large range of small molecules was investigated, revealing only reaction with cuminil to afford the first trivalent lanthanide decaaryllanthanidocene complex SmCpAr-Et2(Ar′C(O)C(O)Ar′) (Ar′ = 4-iPrC6H4). Following the important discovery of recent years on SMM (single molecule magnet) behavior of Dy metallocenes, the quest for even better SMMs continued in 2018. Several new record-holding complexes were synthesized based on polyisopropyl-cyclopentadienyl complexes, with the best complex to date being [(C5iPr5)(C5Me5)Dy] [BAr4], showing magnetic hysteresis up to 80 K and an effective energy barrier to reversal of magnetization Ueff = 1541 cm−1.Several remarkable lanthanide arene complexes have been prepared and structurally characterized. For example, the bimetallic inverse sandwich La2+ complex salt [K(18-crown-6)(THF)2][(Cp″2La)2(μ-η6:η6-C6H6)]·THF (Cp″ = C5H3(SiMe3)2-1,3) reduces hydrocarbons such as naphthalene, anthracene, or cyclooctatetraene to give La3+ complexes of the hydrocarbon anions. Samarium-arene bonding has also been observed in the rare samarium(II) aryloxide Sm(OAriPr6)2 [AriPr6 = −C6H3-2,6-(C6H2-2,4,6-iPr3)2] and in the remarkable tetranuclear samarium(II) inverse sandwich complex (µ-η6:η6-C7H8)[KSmL3]2 (L = OSi(OtBu)3). Several new triple-decker complexes of the type Ln2(COT″)3 (COT″ = bis(trimethylsilyl)cyclooctatetraenyl dianion) have been isolated and structurally characterized. The synthesis and structural characterization of four unsolvated divalent lanthanide cyclononatetraenyl sandwich complexes, Ln(Cnt)2 (Ln = Sm, Eu, Tm, Yb; Cnt = η9-cyclononatetraenyl) have also been achieved. Single-crystal X-ray diffraction studies revealed that these neutral sandwich complexes are rigorously linear. A rare heterobimetallic [1] ferrocenophane terbium(III) complex has been found to exhibit single-ion magnet behavior. Reduction of the scandium precursor Sc(nacnac)(OAr)(OCP) (nacnac– = [ArNC(CH3)]2CH, Ar = 2,6-iPr2C6H3) with KC8 afforded a binuclear scandium complex comprising a unique [OCPPCO]4− central motif formed through P–P radical coupling. Heterobimetallic Sm/Co polyarsenides [(CptttCo)2As4Sm(C5Me4R)2] (Cpttt = 1,2,4-C5H2tBu3, R = Me, nPr) were synthesized from the reaction of divalent Sm complexes Cp*2Sm, Cp*2Sm(THF)2 or (C5Me4nPr)2Sm with [(CptttCo)2(μ,η2:2-As2)2], while the Sm/Sb multimetallic complex [(Cp*2Sm)4(μ4,η2:2:2:2-Sb8)] was synthesized from the oxidation of Cp*2Sm with activated antimony. The chemistry of endohedral lanthanide metallofullerenes continued to be an active field of research in 2018. Significant achievements have also been made in the area of organolanthanide catalysis. For example, a variety of highly active lanthanide catalysts for the polymerization of polar substituted styrene monomers as well as the polymerization of 2-vinylpyridine have been developed. Half-sandwich complexes of scandium have been successfully employed in the copolymerization of myrcene with ethylene and propylene. New organolanthanide-catalyzed reactions include the diastereo- and enantioselective C(sp)–H addition of terminal alkynes to 3,3-substituted cyclopropenes and the catalytic hydrothiomethylation of olefins and dienes with a series of methyl-alkyl sulfides. Moreover, the first-time scandium-catalyzed C(sp3)–H alkylation of N,N-dimethyl anilines with olefins has been investigated. Significantly less results over previous years have been published in 2018 on the use of organolanthanide precursors in materials science.The synthesis and reactivity of complexes with actinide-element multiple bonds, e.g. AcC, AcN, AcP, is a highly active research area. The synthesis of uranium(IV) silyl-phosphino-carbene complexes was reported, among which the bis(carbene) complex [U{C(SiMe3)(PPh2)}(BIMPTMS)(µ-Cl)Li(TMEDA)(µ-TMEDA)0.5]2 (36%) showing a 3-center U–C–P character and a short UCcarbene bond. A rare U(IV) imido species [K(THF)3][(PN)U(NH)(iPr2P(C6H3Me)N(C6H2Me2CH2)] was isolated, in which one of the PN ligands has been cyclometallated. This complex was proposed to have been formed by the addition of the ligand C–H of a nearby methyl group to a uranium nitride intermediate. The synthesis and the diverse reactivity of the first base-free terminal phosphinidene thorium(IV) complex, Th(CptBu3)2(PR), towards heterounsaturated small molecules was reported. The functionalization of CO and tert-butyl nitrile have been reported for a Th(IV) bis(phosphido) complex, (C5Me5)2Th{P(Mes)(H)}2, involving intramolecular proton transfer reactions. The synthesis and characterization of the first Np(II) organometallic complex [K(crypt)][Np(Cp″)3] (crypt = 2,2,2-cryptand, Cp″ = C5H3(SiMe3)2) was achieved by reduction of a trivalent precursor. The synthesis and characterization of a neutral U(II) complex, U(NHAriPr6)2, and the very reactive uranium(III) cation [U(NHAriPr6)2][BArF24] supported by an amido bis(arene) ligand was reported. Good progress has been made in metallofullerene chemistry of the actinides, as evidenced by the structural characterization of the dimetallic actinide endohedral metallofullerene (EMF) U2@C80, revealing short U–U bonding inside the cage. Actinide complexes have also found new applications in catalysis, as shown by the first example of selective hydroboration of aldehydes and ketones using actinide catalysis. Previous article in issue

Two series of lanthanide complexes have been chosen to analyze trends in the magnetic properties and crystal field parameters (CFPs) along the two series: The highly symmetric LnZn16 (picHA)16 series (Ln=Tb, Dy, Ho, Er, Yb; picHA=picolinohydroxamic acid) and the [Ln(dpa)3 ](C3 H5 N2 )3 ⋅3H2 O series (Ln=Ce-Yb; dpa=2,6-dipicolinic acid) with approximate three-fold symmetry. The first series presents a compressed coordination sphere of eight oxygen atoms whereas in the second series, the coordination sphere consists of an elongated coordination sphere formed of six oxygen atoms. The CFPs have been deduced from ab initio calculations using two methods: The AILFT (ab initio ligand field theory) method, in which the parameters are determined at the orbital level, and the ITO (irreducible tensor operator) decomposition, in which the problems are treated at the many-electron level. It has been found that the CFPs are transferable from one derivative to another, within a given series, as a first approximation. The sign of the second-order parameter B 0 2 differs in the two series, reflecting the different environments. It has been found that the use of the strength parameter S allows for an easy comparison between complexes. Furthermore, in both series, the parameters have been found to decrease in magnitude along the series, and this decrease is attributed to covalent effects.

This work investigated a rare earth element (REE) natural biogeochemical cycle in an area with a light rare earth element (LREE)-rich ferrocarbonatite intrusion. An REE determination in this geological environment allowed us to trace REE natural transfers in order to better manage future REE mining exploitations. Our findings suggest that although REE concentrations in abiotic compartments (soil and freshwater systems) and biotic samples (terrestrial and aquatic plants) were low, the LREE fractionation observed in the parent material was maintained along compartments. Additionally, Nd anomalies observed in the sediment pore water suggest a potential different biogeochemical cycle of this element in aquatic systems. According to the potential bioaccumulation of REEs in the organisms of two studied plants belonging to terrestrial and aquatic compartments, Equisetum arvense L. and Typha latifolia L. (respectively), we observed that REEs were not accumulated and that they showed limited REE transfer inside plants, but with an increased uptake of Eu relative to the other REEs. Our results indicated a low mobility and transfer of REEs from REE-rich bedrocks in a natural area toward terrestrial and freshwater systems, but also pointed to a dilution of the REE content in the different compartments, maintaining the LREE fractionation. Our findings provide new knowledge about the REE biochemical cycle in a natural area (from rocks to plants) and represent a starting point for an environmentally friendly exploitation of future REE mining areas., This work was supported by the French National Research Agency through the national program “Investissements d’avenir” with the reference ANR-10-LABX-21-01/LABEX RESSOURCES21. A. Romero-Freire would like to acknowledge support by the COST-European Cooperation in Science and Technology (TD1407: NOTICE).

Texte intégral uniquement accessible aux membres de l'Université de Lorraine; The flotation of fine particles is a technical challenge that the mining industry must address to efficiently exploit certain types of deposit whose ores are finely textured. This issue is of particular importance with the depletion of mineral resources considered as “conventional” with regards to the liberation mesh of minerals of interest. There are two basic approaches to optimise the flotation process for a particular ore, the research for the best working parameters of existing flotation devices and the development of new flotation reagents. The research works in the past decades highlight that, owing to their high hydrodynamic regimes, intensive flotation technologies are more adapted to the treatment of fine particles than conventional mechanical flotation devices. However, due to the short residence time in intensive flotation cells, it is essential that the surface of the minerals of interest has been particularly hydrophobised. In this sense, the improvement of the flotation performance for fine grained ores implies both the use of new flotation technologies and the development of more efficient and more selective flotation reagents. The selected object of studies is a fine grained residue produced after the extraction of gold and tellurium out of the ore from the Kankberg mine which is located in Sweden. This fine material contains low amounts of rare earth elements, in the form of monazite, a phosphate mineral. The thesis works presented in this manuscript consists of developing a reagent that improves the adsorption of the collector on the surface of monazite to facilitate its recovery throughout intensive flotation. The conducted studies emphasise that lanthanum ions significantly promote the adsorption of carboxylate type collectors on the monazite surface thereby increasing the floatability of this mineral. Current knowledge regarding the surface properties of monazite and the mechanism of anionic collectors adsorption on the monazite surface are relatively limited. Therefore, it seems wise to contribute to improving this knowledge during this thesis. A study was carried out to assess the hydroxylation of the monazite surface which is largely considered in the literature as a phenomenon influencing the collector adsorption. The handling of monazite may cause radiation exposure because of the radioactive decay chains of the actinide elements naturally present in the monazite crystal lattice. During this thesis, the synthesis of indurated monazite analogue materials was also investigated to facilitate the conduct of experiments. A protocol of synthesis of monazite powder sufficiently indurated to be mechanically stirred has been developed. Electrophoretic mobility measurements highlight that the surface properties of the synthetic monazite materials were similar to those of natural monazite with complex chemistry showing, in addition, that the presence of several atom substitutions in the monazite crystal lattice has no influence on its electrophoretic mobility.; La flottation des particules fines est un challenge technique que l’industrie minière doit relever pour pouvoir exploiter de manière optimale certains types de gisement dont les minerais présentent des textures particulièrement fines. Cette problématique revêt une importance particulière avec la diminution des ressources minérales considérées comme conventionnelles du point de vue de la maille de libération des minéraux d’intérêt. Il existe deux manières d’optimiser les procédés de flottation pour un minerai, la recherche des paramètres de fonctionnement optimaux des équipements de flottation existants et l'élaboration de nouveaux réactifs de flottation. Les travaux des dernières décennies ont mis en évidence qu’en raison de leurs hauts régimes hydrodynamiques favorisant le contact entre les bulles et les particules, les techniques de flottation intensive étaient beaucoup plus adaptées pour le traitement des fines que les dispositifs de flottation mécanique. Cependant, en raison du temps de résidence très court au sein de ces dispositifs de flottation, il est nécessaire que la surface des minéraux d’intérêts soit rendue particulièrement hydrophobe. En ce sens, l’amélioration des performances de flottation, pour les minerais à granularité réduite, par des techniques de flottation intensive requiert l’élaboration de réactifs de flottation plus efficaces et plus sélectifs. L’objet d’étude qui a été choisi est un résidu fin produit à l’issue des différentes étapes nécessaires à l’extraction de l’or et du tellure à partir du minerai de la mine de Kankberg en Suède. Ce résidu à granularité fine possède une faible teneur en terres rares présentes sous la forme de monazite, un minéral de type phosphate. Les travaux de thèse présentés dans ce manuscrit consistaient à développer un réactif permettant d’améliorer l’adsorption d’un collecteur sur la surface de la monazite pour faciliter sa récupération lors de la flottation intensive. Il ressort de ces études que les ions lanthane peuvent améliorer significativement l’adsorption des collecteurs de type carboxylate sur la surface de la monazite et donc améliorer la flottabilité de cette dernière. Les connaissances actuelles concernant les propriétés de surface de la monazite et les mécanismes d’adsorption des collecteurs anioniques sur la surface de ce minéral sont relativement limitées. Il paraissait donc judicieux de contribuer au cours de cette thèse à l’amélioration de ces connaissances. Une étude a été menée pour évaluer l’hydroxylation de surface de la monazite qui est largement considérée dans la littérature comme influençant l’adsorption du collecteur. La manipulation de monazite peut conduire à une exposition aux radiations en raison de la radioactivité émise par la chaîne de désintégration des actinides souvent présents en quantité significative dans le réseau cristallin de la monazite. Au cours de ce projet doctoral, la synthèse de matériaux indurés analogues à la monazite a également été étudiée dans le but de faciliter le déroulement des expérimentations qui nécessitent l’utilisation de monazite. Un protocole de synthèse de poudre de monazite suffisamment indurée pour être agitée a été développé. Des mesures de mobilité électrophorétiques ont par ailleurs montré que les propriétés de surface de ces monazites de synthèse sont identiques à celles d’une monazite naturelle à composition complexe démontrant par ailleurs que la présence de nombreuses substitutions atomiques dans le réseau cristallin de la monazite n’avait pas d’influence sur sa mobilité électrophorétique.

Texte intégral uniquement accessible aux membres de l'Université de Lorraine; The flotation of fine particles is a technical challenge that the mining industry must address to efficiently exploit certain types of deposit whose ores are finely textured. This issue is of particular importance with the depletion of mineral resources considered as “conventional” with regards to the liberation mesh of minerals of interest. There are two basic approaches to optimise the flotation process for a particular ore, the research for the best working parameters of existing flotation devices and the development of new flotation reagents. The research works in the past decades highlight that, owing to their high hydrodynamic regimes, intensive flotation technologies are more adapted to the treatment of fine particles than conventional mechanical flotation devices. However, due to the short residence time in intensive flotation cells, it is essential that the surface of the minerals of interest has been particularly hydrophobised. In this sense, the improvement of the flotation performance for fine grained ores implies both the use of new flotation technologies and the development of more efficient and more selective flotation reagents. The selected object of studies is a fine grained residue produced after the extraction of gold and tellurium out of the ore from the Kankberg mine which is located in Sweden. This fine material contains low amounts of rare earth elements, in the form of monazite, a phosphate mineral. The thesis works presented in this manuscript consists of developing a reagent that improves the adsorption of the collector on the surface of monazite to facilitate its recovery throughout intensive flotation. The conducted studies emphasise that lanthanum ions significantly promote the adsorption of carboxylate type collectors on the monazite surface thereby increasing the floatability of this mineral. Current knowledge regarding the surface properties of monazite and the mechanism of anionic collectors adsorption on the monazite surface are relatively limited. Therefore, it seems wise to contribute to improving this knowledge during this thesis. A study was carried out to assess the hydroxylation of the monazite surface which is largely considered in the literature as a phenomenon influencing the collector adsorption. The handling of monazite may cause radiation exposure because of the radioactive decay chains of the actinide elements naturally present in the monazite crystal lattice. During this thesis, the synthesis of indurated monazite analogue materials was also investigated to facilitate the conduct of experiments. A protocol of synthesis of monazite powder sufficiently indurated to be mechanically stirred has been developed. Electrophoretic mobility measurements highlight that the surface properties of the synthetic monazite materials were similar to those of natural monazite with complex chemistry showing, in addition, that the presence of several atom substitutions in the monazite crystal lattice has no influence on its electrophoretic mobility.; La flottation des particules fines est un challenge technique que l’industrie minière doit relever pour pouvoir exploiter de manière optimale certains types de gisement dont les minerais présentent des textures particulièrement fines. Cette problématique revêt une importance particulière avec la diminution des ressources minérales considérées comme conventionnelles du point de vue de la maille de libération des minéraux d’intérêt. Il existe deux manières d’optimiser les procédés de flottation pour un minerai, la recherche des paramètres de fonctionnement optimaux des équipements de flottation existants et l'élaboration de nouveaux réactifs de flottation. Les travaux des dernières décennies ont mis en évidence qu’en raison de leurs hauts régimes hydrodynamiques favorisant le contact entre les bulles et les particules, les techniques de flottation intensive étaient beaucoup plus adaptées pour le traitement des fines que les dispositifs de flottation mécanique. Cependant, en raison du temps de résidence très court au sein de ces dispositifs de flottation, il est nécessaire que la surface des minéraux d’intérêts soit rendue particulièrement hydrophobe. En ce sens, l’amélioration des performances de flottation, pour les minerais à granularité réduite, par des techniques de flottation intensive requiert l’élaboration de réactifs de flottation plus efficaces et plus sélectifs. L’objet d’étude qui a été choisi est un résidu fin produit à l’issue des différentes étapes nécessaires à l’extraction de l’or et du tellure à partir du minerai de la mine de Kankberg en Suède. Ce résidu à granularité fine possède une faible teneur en terres rares présentes sous la forme de monazite, un minéral de type phosphate. Les travaux de thèse présentés dans ce manuscrit consistaient à développer un réactif permettant d’améliorer l’adsorption d’un collecteur sur la surface de la monazite pour faciliter sa récupération lors de la flottation intensive. Il ressort de ces études que les ions lanthane peuvent améliorer significativement l’adsorption des collecteurs de type carboxylate sur la surface de la monazite et donc améliorer la flottabilité de cette dernière. Les connaissances actuelles concernant les propriétés de surface de la monazite et les mécanismes d’adsorption des collecteurs anioniques sur la surface de ce minéral sont relativement limitées. Il paraissait donc judicieux de contribuer au cours de cette thèse à l’amélioration de ces connaissances. Une étude a été menée pour évaluer l’hydroxylation de surface de la monazite qui est largement considérée dans la littérature comme influençant l’adsorption du collecteur. La manipulation de monazite peut conduire à une exposition aux radiations en raison de la radioactivité émise par la chaîne de désintégration des actinides souvent présents en quantité significative dans le réseau cristallin de la monazite. Au cours de ce projet doctoral, la synthèse de matériaux indurés analogues à la monazite a également été étudiée dans le but de faciliter le déroulement des expérimentations qui nécessitent l’utilisation de monazite. Un protocole de synthèse de poudre de monazite suffisamment indurée pour être agitée a été développé. Des mesures de mobilité électrophorétiques ont par ailleurs montré que les propriétés de surface de ces monazites de synthèse sont identiques à celles d’une monazite naturelle à composition complexe démontrant par ailleurs que la présence de nombreuses substitutions atomiques dans le réseau cristallin de la monazite n’avait pas d’influence sur sa mobilité électrophorétique.

Scandium, yttrium and lanthanides (REE) are critical raw materials in increasing demand for modern technology, so identifying and developing new sources of REE has become a pressing need. REE concentrations in acid mine drainage (AMD) are several orders of magnitude higher than those in natural water, and their recovery is of economic interest. Passive remediation systems designed to minimize AMD impact on the ecosystem retain REE in solid waste, where basaluminite, Al4SO4(OH)10·5H2O, is the mineral responsible for the scavenge. However, no information about the retention mechanisms of REE is currently available in the literature. The objective of the present work is to study the adsorption of lanthanides, yttrium and scandium onto synthetic basaluminite over a pH range of 4–7 at room conditions. Since sulfate is ubiquitous in AMD, the adsorption has been investigated with variable sulfate concentrations. Experimental results show that sorption onto basaluminite is strongly dependent on pH, starting at pH 5 for lanthanides and yttrium and at pH 4 for scandium. At any given pH values, sorption increases with sulfate concentration. Distribution coefficients, defined as KD = [REEsorbed]/[REEsolution], are higher for Sc, and across the lanthanide series, the distribution coefficients increase from La to Lu according to decreasing ionic radius, where yttrium is considered close to Ho. Experimental results were modeled using a sorption model that considers mass law equations where the strong sulfate aqueous complex, MSO4 +, is adsorbed by exchanging a proton with the mineral surface. The dependence of the experimental results on pH suggests the formation of monodentate binding for Y and lanthanides. The bidentate complex for Sc is deduced by the two proton exchange per mol of Sc extracted from the experiments. The thermodynamic constants for the surface complexation reactions were obtained from experiments with high sulfate concentration and were successfully applied to the experiment with low sulfate content and different solid-liquid ratios. Therefore, the model can be applied to interpret the REE geochemistry in natural systems with variable pH and sulfate concentrations. © 2019 Elsevier Ltd, This work was funded by the European EIT ‘Morerecovery’ and the Spanish SCYRE (CGL2016-78783-C2-R)] projects. A. L. was also funded by the FPI grant (BES-2014-069978) Ministry of Science, Innovation and Universities (Spain). The authors wish to thank J. Bellés, M. Cabañas, R. Bartrolí and N. Moreno (IDAEA-CSIC) for their analytical assistance. The manuscript has been greatly improved with the comments of Prof. Villalobos and three anonymous reviewers.

International audience; Dedicated to Professor Miguel Julve on the occasion of his 65 th birthday, and for its outstanding contribution to the field of coordination chemistry and molecular magnetism. Abstract The deposition of Single-Molecule Magnets (SMMs) on surfaces is a mandatory step toward their possible use as data-storage units or qubits. In this study we report the structural and magnetic characterization of two parent compounds of a well-known SMM called DyPyNO, ([Dy(hfac) 3 (PyNO)] 2 with hfac = hexafluoroacetylacetonate and PyNO = pyridine-N-oxide), that are targeted to be deposited on gold surfaces. Thio-substitution of the pyridine ring of these dimers is expected to provide good anchoring group toward deposition on gold. We have investigated two significantly different geometries of the anchoring groups in dimers 1 and 2. Interestingly, despite these strong differences, SMM behavior is remarkably well-preserved in the polycrystalline material offering possibilities to graft these SMMs on surface.

International audience; A new tripodal ligand, based on a central nitrogen atom tris‐functionalized with 6‐methylene‐2‐pyridyl phosphonic acid was synthesized and characterized, in particular by its X‐ray crystal structure. The coordination behaviour of the tripod with lanthanide cations in aqueous solutions was studied by means of UV/Vis electronic absorption spectroscopy and steady‐state and time‐resolved luminescence spectroscopy, revealing the formation of a [LnL] complex followed by polynuclear species with 2:1 and 3:1 metal/ligand stoichiometries. The [LnL] complexes (Ln = Eu, Tb and Yb) were isolated and characterized and the solid‐state structure of the Eu complex was determined by X‐ray diffraction analysis on monocrystals, revealing the observation of dimeric species, in which the Ln3+ cations are firmly held in the cavity formed by the three pyridylphosphonate arms, the coordination of the cations being completed by a water molecule and a phosphonate function of the second complex, allowing for the formation of the dimers, which are further stabilized by π–π stacking interactions between one pyridyl unit of each adjacent monomer. The spectroscopic properties of the complexes in aqueous solutions were studied, showing an impressive 16 µs excited state lifetime for the Yb complex in D2O, despite the presence of a water molecule in the first coordination sphere.

International audience; Luminescent Single-Molecule Magnets (SMM) belong to a new class of multifunctional molecule-materials that associate luminescence and slow relaxation of their magnetization within a single crystalline phase. We present in this mini-review the major advances that have been achieved in this new field over the last few years. More particularly, we will focus on the use of Schiff-base complexes in order to correlate magnetism and luminescence, as well as discussing the future outlooks of the field.

In the framework of development of new processes for spent nuclear fuel reprocessing, new extractant molecules are studied.The goals of this thesis are to study the molecular and supramolecular speciation of representative organic solutions. The speciation was determined by coupling experimental and theoretical study. After solute extraction, the composition of the organic solutions is experimentally determined. Simulations boxes with the same composition than experimental solutions are build. After simulation, trajectories are used to calculate small angle scattered intensities. The representativeness of the simulations is checked by comparison of experimental and calculated scattered intensities. The use of the simulation, ESI-MS spectrometry and IR spectroscopy provides the description of the structures in organic solution at the molecular and supramolecular scale. This methodology was applied on water and uranyl nitrate extraction by the monoamide DEHBA and MOEHA and by the malonamide DMDOHEMA as well as the extraction of water and neodymium nitrate by TODGA solutions.The extraction of water is dependent of the organization of the solution: monoamide solution made of monomer and dimer solubilize few amount of water in comparison with DMDOHEMA or TODGA solutions.The extraction of uranyl nitrate showed different behavior. UO2(NO3)2L2 complexes are observed at low uranium concentration after extraction by the monoamides. Polymetallic species are observed with the increase of uranium concentration. In the case of DMDOHEMA, monometallic complexes are majority but without a unique stoichiometry. The uranyl can be linked to 1 o 2 malonamides, 2 nitrates and sometimes to a water molecule. Neodymium is extracted by TODGA within small aggregates made of 2 or 3 cations liked by bridging nitrates. The increase of the concentration of neodymium leads to a phase separation. The presence of octanol provides the extraction of higher concentration of neodymium nitrate. Simulations showed the replacement of water and TODGA molecules and the first coordination sphere of the cation with octanol molecule. This increases the solubility of the aggregates. The presence of DMDOHEMA prevents also the phase separation by structuring the solution. With malonamide, smaller aggregates are observed.For both systems, phases after demixing (third phase formation) were characterized.This work provides the study of the molecular and supramolecular organization of organic solutions by combining experimental studies and molecular dynamic simulations., Dans le cadre du développement de nouveaux procédés par extraction liquide-liquide pour le recyclage du combustible nucléaire usé, de nouvelles molécules extractantes sont à l’étude. Les molécules à fonction amide (monoamide, malonamide ou diglycolamide) sont particulièrement étudiées. Les objectifs de cette thèse sont d’étudier la spéciation moléculaire et supramoléculaire de solutions organiques représentatives des différents procédés en cours de développement. Cette spéciation a été réalisée en couplant des études expérimentales et théoriques. Après extraction de solutés, la composition des solutions organiques est déterminée expérimentalement. Des boites de simulation par dynamique moléculaire ayant la même composition que les solutions expérimentales sont ensuite construites. Après simulation, les trajectoires de dynamique moléculaire permettent de calculer les masses volumiques et les intensités diffusées aux petits angles théoriques des solutions simulées. Dès lors que les données calculées et les données expérimentales sont en accord, on estime que les simulations sont représentatives des solutions réelles. Ces simulations couplées à des caractérisations expérimentales supplémentaires (spectroscopie infra-rouge – IR – et spectrométrie de masse à ionisation par électrospray – ESI-MS –) permettent de décrire les structures en solution à la fois à l’échelle moléculaire et supramoléculaire. Cette méthodologie a été appliquée à l’extraction d’eau et de nitrate d’uranyle par les monoamides DEHBA et par le malonamide DMDOHEMA ainsi qu’à l’extraction d’eau et de nitrate de néodyme par des solutions à base de TODGA.L’extraction d’eau en phase organique est dépendante de l’organisation de la solution : les solutions de monoamides essentiellement constituées de monomères et dimères solubilisent peu d’eau contrairement aux solutions de DMDOHEMA ou de TODGA majoritairement constituées d’agrégats. L’extraction de nitrate d’uranyle a mis en évidence différents comportements dépendant de la structure de la molécule ou de la concentration d’uranyle. Des complexes UO2(NO3)2L2 sont observés à faible concentration d’uranium après extraction par les monoamides. Lorsque la concentration d’uranium augmente, des espèces polymétalliques sont observées et deviennent majoritaire en solution. Dans le cas du DMDOHEMA, des complexes monométalliques sont majoritaires mais n’ont pas une stœchiométrie unique. L’uranyle peut être coordiné à 1 ou 2 malonamides (monodenté ou bidenté), 2 nitrates et parfois une molécule d’eau. Le néodyme est extrait par le TODGA dans l’heptane sous forme de petits agrégats contenant 2 ou 3 cations liés par des nitrates pontants. Une augmentation de la concentration de néodyme entraine une augmentation de l’agrégation jusqu’à l’apparition d’une démixtion de phase. La présence d’octanol (0,3 mol/L) permet d’extraire une plus forte concentration de Nd sans séparation de phase. Les simulations ont montré que l’octanol se place dans la 1ère sphère de coordination du néodyme à la place des molécules d’eau ou de TODGA améliorant ainsi la solubilité des complexes et agrégats dans la phase organique. L’ajout de 0,5 mol/L de DMDOHEMA à une solution de TODGA permet également d’éviter la démixtion en structurant la solution. En présence de malonamide des agrégats plus petits sont observés.Pour les deux systèmes étudiés (mono et diamides), les phases obtenues après démixtion de la phase organique (phénomène de formation de 3ème phase) ont également été caractérisées.Ces travaux ont permis de déterminer l’organisation moléculaire et supramoléculaire dans des solutions d’extraction par l’utilisation d’une méthode couplant études expérimentales et simulations par dynamique moléculaire.

Molecular materials, and in particular those based on Lanthanides, have been extensively studied for their use in data storage, spintronics and quantum computing, as they promise high anisotropic systems and magnetic bistability of the discrete entity. Actually, in Athe last twenty-five years a plethora of compounds have been reported, thus showing slow of their magnetic relaxation and the characteristic magnetic hysteresis at low temperature. Moreover, some of the last investigations have reach blocking temperatures (temperature for which the system shows superparamagnetic behavior) at the liquid nitrogen level, hence facilitating the applicability of devices based on these molecules. However, the slow relaxation is commonly accompanied by quantum phenomena, favoring a fasten relaxation. The quantum effects open the possibility to different magnetic objects, but only if the operating mechanisms are well known. Dipolar interactions, with the neighboring molecules, and hyperfine interactions, with the metal ion, are known to be some of the reasons why this fast relaxations occurs. With the aim of acquiring a better understanding of the quantum events, and the contribution of the different interactions, different systems have been chosen to be studied in this work. Thus, the synthesis and magnetic characterization of magnetically diluted (suppression of dipolar interactions) and isotopic enrichment (tuning of the hyperfine interactions) of the different systems have been performed in order to find a general direction for the optimization of the slow relaxation process., Les matériaux moléculaires, et plus précisément ceux à base d’ions lanthanides, ont été largement étudiés pour leur utilisation dans différentes applications, dont le stockage de l’information ou l’ordinateur quantique. Cet intérêt s’explique du fait que des systèmes contenant des ions lanthanides donnent lieu à une large anisotropie et une bistabilité magnétiques d‘origine purement moléculaire. Durant les vingt-cinq dernières années, beaucoup d’articles ont été publiés dans lesquels les composés à base de ces ions montraient une relaxation lente de leur aimantation et une hystérèse magnétique à basse température. Récemment, des recherches ont menées à l’obtention de systèmes moléculaires présentant des températures de blocage (température maximale à laquelle le système se comporte comme à superparamagnétique) proche de l’azote liquide ce qui facilite le transfert dans des dispositifs basés sur ces systèmes.Cependant, cette relaxation lente de l’aimantation est souvent accompagnée des phénomènes quantiques, donnant lieu à d’autres relaxations beaucoup plus rapides. Les phénomènes quantiques peuvent donner lieu à de nouvelles applications mais à condition de bien comprendre leurs mécanismes d’action. Les interactions dipolaires et les hyperfines, les premiers provenant des molécules voisines et la deuxième de l’interaction spin-noyau dans le métal, sont connus pour participer à l’origine de ces phénomènes. Quelques systèmes ont été choisis durant ce travail de thèse dans le but de mieux comprendre les évènements quantiques et la contribution des différentes interactions. Ceci a mené à la synthèse et aux caractérisations magnétiques de différents systèmes magnétiquement dilués (étude des interactions dipolaires) et isotopiquement enrichis (étude des interactions hyperfines), afin de mettre en évidence une tendance générale pour l’optimisation des processus de relaxation lente.

International audience; Our society heavily depends on the availability of raw materials. Technology metals such as rare earth elements (REEs) are vital in many applications. Because their virgin mining and production is constrained by a multitude of factors, future exploitation of secondary sources is strongly considered. Tailings from past and present mining activities are important sources of REEs and other critical raw materials, e.g., tungsten and phosphate. The possibility of processing such tailings was thoroughly investigated in the ENVIREE European Project (2015-2018). In this paper, we assess the use of solvent extraction to recover REEs from tailings originating from New Kankberg (Sweden) and Covas (Portugal). Extraction of REEs from common mineral acid solutions was carried out using solvating (Cyanex 923 and TODGA) and acidic extractants (DEHPA and Cyanex 572). Extraction was studied in the presence of high amounts of phosphate, iron and copper in solution. This was to identify bottlenecks in the separation process and ways to mitigate them. While copper and phosphate didn't pose significant issues, iron was co-extracted with the REEs in several systems, e.g., DEHPA - sulfuric acid. Co-extraction was reduced by using a blended DEHPA - Cyanex 923 organic phase. At the same time, the extraction efficiency of REEs improved. Control of the contact time between the aqueous and organic phase, and selective stripping were also used to effectively mitigate the extraction of iron. (C) 2019 Elsevier Ltd. All rights reserved.

In this study, the atom substitutions that commonly affect the monazite lattice were considered as potential factors affecting the monazite electrophoretic mobility. The influence of light rare earth elements (LREE) substitutions and the presence of thorium, calcium, and silicate within the monazite crystal lattice was also examined using a natural monazite and synthetic cerium, lanthanum and neodymium monazite materials. Electrophoretic mobility measurements performed after treatment in an electrolyte solution equilibrated with air outline that LREE substitutions and other substitutions observed in the tested natural monazite did not affect the mineral surface properties. Conversely, the electrophoretic mobility of the synthetic monazites was found to be significantly affected by the amount of dissolved carbonate species present in the aqueous media. More precisely, carbonate species were found to decrease the electrophoretic mobility of monazite. Unlike tests performed with a solution equilibrated with air, the electrophoretic mobility of monazite treated in a CO2 depleted electrolyte solution, under controlled atmosphere, were found erratic. This highlights the difficulty in obtaining reliable electrophoretic mobility data when the carbonate content in the supporting electrolyte solutions is not controlled.

International audience; Nanoparticles with strong paramagnetic responses are of prime interest for advanced MRI imaging. To replace Gd expensive and toxic complexes, Gd-based nanoparticles have emerged as a viable solution for efficient and harmless MRI contrast agents. Gadolinium oxysulfide nanoparticles could represent suitable candidates for MRI imaging and bimodal imaging thanks to their excellent properties as host matrix and chemical stability, but their magnetic properties at the nanoscale have been hitherto poorly investigated especially in the case of ultrafine nanoparticles (< 10 nm), where surface effects and ligands can significantly affect the magnetic behavior. In the present work, we synthesized and characterized bimetallic (Gd,Ce) 2 O 2 S nanoparticles and demonstrated that they are paramagnetic over a wide 2 temperature range including the body one. The mixture of Gd and Ce magnetic centers enables a fine control of the magnetic properties up to high Ce concentrations (80 %) and over a large range of magnetic moments, while photoemission properties are guaranteed up to 20 % of Ce owing to a regular dispersion of the Ce centers. The present study on bimetallic oxysulfide nanoparticles with high concentrations of two lanthanides shows that (Gd,Ce) 2 O 2 S nanoparticles are viable candidates as tunable nanoscaled agents for bimodal imaging.

This article aimed at reviewing the advances on the development of paramagnetic complexes used as chemical exchange saturation transfer agents in magnetic resonance imaging. This relatively new type of contrast opens new avenues in the development of MRI probes for molecular imaging, and coordination chemistry lies at the center of such advances. Strategies to detect important biomarkers such as pH, cations, anions, metabolites, enzyme, and O2 were described. The current challenges, limitations, and opportunities in this field of research were discussed.