Nous avons développé un microscope d’imagerie de fluorescence destiné à localiser,et à évaluer la concentration, d’un agent de contraste IRM macromoléculaire (P717) incluant du Gd, destiné à identifier les lésions athérosclérotiques. Comme l’agent de contraste n’est pas naturellement fluorescent, nous l’avons modifié en substituant des ions Tb aux ions Gd,ce qui ne modifie pas ses propriétés chimiques vis-à-vis de l’artère. Comme sa constante de temps est très supérieure à celle des autres sources de fluorescence, nous obtenons un bon rapport signal sur bruit, malgré une faible émission, par une technique de résolution temporelle.La source d’excitation, sur le microscope inversé, est une diode laser émettant à 371nm, le capteur est une caméra ICCD. Nous mesurons aussi le spectre de la fluorescence pour nous assurer que le signal provient réellement de l’agent étudié. Un microcontrôleur permet de gérer automatiquement la synchronisation de toutes les parties du système. Pour l’identification des tissus par un anatomo-pathologiste, nous prenons aussi une photo en« couleurs naturelles » en prenant successivement trois images aux trois couleurs fondamentales. Ensuite, notre logiciel assemble toutes les images en couleurs et en fluorescence.Les premières images que nous avons prises sur des artères de rat nous prouvent que l’agent de contraste est effectivement localisé dans des régions spécifiques. Nous disposons maintenant d’un outil nous permettant de comprendre l’attachement d’un agent de contraste IRM sur une artère et qui nous permettra d’optimiser cet agent. / We developed a fluorescence imaging microscope system intended for localizing and evaluating its concentration with in arteries slices of a macromolecular (P717) Gd-based MRIcontrast agent used for the visualization of atherosclerotic lesions. As the contrast agent is not initially fluorescent, we modified the agent which is now partially fitted with Tb ions, while preserving its chemical characteristics. A long fluorescence emission time constant enables usto have a suitable signal to noise ratio, despite a low intensity, using pulsed illumination and time gated imaging after the other sources of fluorescence have decayed.The excitation source, on top of the inverted microscope, is a laser diode emitting at 371nm. The fluorescence signal is imaged on an ICCD camera. The fluorescence spectrum is acquired too, to positively insure that the signal really comes from the intended contrast agent. A microcontroller synchronizes electrical gating of the ICCD camera, of the laser pulse and generally controls automatically all parts of the measurement process. For tissue identification, we acquire a “natural image” using the standard halogen lamp of themicroscope. This image is synthesized by the use of the combination of three successive images taken with the three fundamental colors. Then our software assembles the color and fluorescence images.First images of rat arteries show that the contrast agent is indeed localized on specific regions of the tissues. We now have a new tool which allows us to understand and optimize the MRI contrast agent.

La thèse s’insère dans le cadre d’études menées sur la conversion d’actinides en oxydes par le biais de précurseurs solides oxalate obtenus par précipitation ou cristallisation. Une compréhension poussée de cette étape initiale de formation de la phase solide à partir des éléments en solution est essentielle, car les caractéristiques morphologiques et structurales du précurseur oxalate contribuent à orienter le comportement aux opérations de pastillage et frittage de l’oxyde. Le travail de thèse est centré sur l’influence des paramètres physico-chimiques de précipitation et porte, en premier lieu, sur des systèmes simples simulants des actinides. Une étude de la cristallisation de l’oxalate de néodyme(III) permet ainsi d’identifier différents hydrates d’oxalate(III), dont la structure cristalline est en lien avec différentes morphologies. Les tendances dégagées orientent la suite des essais concernant la précipitation de l’oxalate de néodyme(III), phénomène plus difficilement maîtrisé que la cristallisation. Notamment, les paramètres température et ajout d’additifs dits « structurants » ou « non structurants » sont retenus. L’étude est enfin étendue à l’oxalate de thorium(IV) et à l’oxalate mixte thorium(IV)-néodyme(III) avant d’être appliquée à l’oxalate de plutonium(III). Les essais de précipitation réalisés sur ce dernier système aboutissent à l’obtention d’oxalates de plutonium de structure et/ou de morphologie différente et, par conséquent, d’oxydes de morphologie différente. / This work is in line with studies concerning actinides conversion by oxalic precipitation. This process leads to the precipitation of actinide oxalate compounds used as oxides precursors. As oxalate compounds keep their morphology through a pseudomorphic transformation when calcined into oxides, having control over their morphology is a key aspect for the control of some oxides properties. The thesis deals with the influence of physical-chemical parameters of oxalic precipitation and concerns, at first, surrogate systems of actinides. Neodymium(III) oxalate crystallization is firstly studied, and enables the identification of several Nd(III) oxalate hydrates with various morphologies, which depend on their crystalline structure. This preliminary study is used to guide the next part of the work dedicated to the study of neodymium(III) oxalate precipitation, this phenomenon being even more difficult to control than crystallization. Parameters such as temperature and influence of “structuring” and “non structuring” additives are studied. The study is then extended to thorium(IV) oxalate and mixed thorium(IV)-neodymium(III) oxalate before its application to plutonium(III) oxalate system. The experiments concerning this last system result in the obtention of plutonium oxalates with different structure and/or morphology, which, consequently, leads to plutonium oxides with different morphology.

In this thesis, the chemistry of lanthanide and actinide complexes of Schiff-base, polypyrrolic macrocyclic ligands has been evaluated. Chapter one introduces some general chemistry of uranium before focussing on uranium(III) and (IV) coordination complexes of nitrogen donor ligands. The surface chemistry of uranium metal is also briefly discussed along with the synthesis of uranium borohydride, hydride and alkyl complexes. Chapter two describes the synthesis and characterisation of the monometallic complexes [M(L)] or [M(HL)], where M = Y, Ce, and U, of the octadentate Schiffbase pyrrole macrocycle H4L. In particular, these complexes display a new binding mode of the macrocycle which leads to the formation of the unique trinuclear supramolecular complexes [M(HL)]3, (M = Ce, Y). Reactions of these materials towards hydrolysis, oxygen sources and other metal reagents are also exemplified. Chapter three details the synthesis and characterisation of the bimetallic complexes, [(MX)2(L)], where M = Ce, U, and Np and X = I or Cl, and [(MX2)2(L)], where M = U, and the attempts to transform these complexes into metal hydrides via their borohydrides. The solid state variable temperature magnetism of the binuclear U(III) and Np(III) complexes was recorded and was found to be consistent with the formation of iodide-bridged, polymeric structures. Chapter four explores the synthesis and reactions of adducts between UI3 and neutral macrocyclic ligands that incorporate either oxygen or nitrogen donors such as crown ethers and cyclam, respectively. The new synthesis of the key starting material, unsolvated UI3 is also outlined, along with the full characterisation of UI4(OEt)2.

While copper is an essential micronutrient in all living organisms, copper misregulation in humans is associated with neurodegenerative disorders such as Menkes and Wilson’s diseases, amyotrophic lateral sclerosis and Alzheimer’s disease. Furthermore, copper is a widely-produced pollutant and thus the detection of Cu(II) and Cu(I) has received much attention in recent years. Copper can be detected in a number of ways including; quenching of fluorescence upon the binding of paramagnetic Cu(II) (a "turn-off" response); augmentation of fluorescence upon Cu(II) binding due to PET modulation (a "turn-on" response); and selective Cu(II)- or Cu(I)-catalysed reactions where the luminescence of the product is distinctly different to that of the starting material. A review of Cu(I) and Cu(II) sensors is described herein. The Hulme group has previously developed a sensor for ligand-bound copper(I) utilising the copper(I)-catalysed [GS-−Cu(I)] variant of the Huisgen 1,3-dipolar cycloaddition reaction. Cu(I)-catalysed alkyne-azide cycloaddition (CuAAC or “click”) was carried out between an alkynyl Eu(III)-DOTA complex and a dansyl azide yielding a 1,4-triazole with a modest turn-on response (10-fold increase in luminescence). The project described herein aimed to achieve a more significant increase in lanthanide luminescence intensity through alteration of the donor moeity, lanthanide ion, and linker length between donor and acceptor moiety. The synthesis of several lanthanide-DOTA complexes, azido fluorophores and the formation of novel Cu(I)-sensors via CuAAC is described herein. All Cu(I) sensors were excited at their individual λex and their lanthanide luminescence intensity was measured using a timedelayed phosphorimeter. The DOTA structural motif has the ability to complex a plethora of potentially useful radionuclides including; yttrium, indium, gallium, lutetium and gadolinium. In general, DOTA-complexes doped with gadolinium are utilised for the identification of tumour sites while yttrium or indium complexes are used for tumour treatment. Biotin-DOTA conjugates have previously been used for pretargeted cancer imaging and radiotherapy. Biotinidase degradation of the amide bond in some biotin constructs has been reported, rendering them unable to bind to the pre-targeted antibody-(strept)avidin site. A novel biotinyl azide lacking this vulnerable amide bond is reported, with potential for bioconjugation to a variety of biomolecules via “click” chemistry. The synthesis of two novel biotinylated Gd-DOTA complexes, with prospective application as pretargeted MRI contrast agents, are also described.

Luminescent lanthanide complexes have been widely studied for various biotechnology and materials science uses, however, the application of these luminescent systems in metallopolymers has been relatively limited, especially when compared to those incorporating transition metal complexes. The unique and interesting photophysical properties of lanthanide complexes (i.e., high color purity and long radiative lifetimes) make these systems ideal for the development of luminescent metallopolymers, which are a unique class of hybrid materials that synthetically incorporate metal centers into organic polymers, thereby taking advantage of the beneficial properties of both traditional inorganic (i.e., catalysis, optics, electronics) and organic (i.e., easy to process, flexible, low weight) materials. A new class of lanthanide complexes exhibiting metal-based visible and near-IR photoluminescence has been designed, synthesized and fully characterized by melting point, ESI-MS, elemental analysis and single crystal and powder X-ray diffraction (when possible). The photophysical properties of these luminescent monomer complexes were studied in solution and the solid state, with the emission spectra displaying the characteristic line-like emission peaks of the trivalent lanthanide ions. This indicates efficient energy transfer from ligand centered excited states to the emissive excited states of the lanthanides. The monomer complexes have been electropolymerized, resulting in conducting metallopolymers that display metal-based photoluminescence. Because these hybrid materials retain the desirable properties of both inorganic semiconductors and organic polymers, such as near metallic electrical conductivity, ease of processing, flexibility and light weight, they are promising for applications in solid-state lighting. / text

Luminescent lanthanide complexes are gaining an increasing amount of interest for their applications in various fields such as OLEDs, immunoassays, analytical sensors, and optical communication. They are promising candidates as light-emitting materials in OLEDs to overcome the difficulty of obtaining pure emission colors with conjugated polymers or small organic molecules. N,N-di(pyridin-2-yl)quinolin-8-amine, a novel blue-emitting ligand, was synthesized to coordinate to europium(III). Experimental studies led to insights of its reactivity with europium acetylacetonate complexes. A new Eu(III) complex based on the diazafluorene ligand was synthesized. A sharp emission band was observed, demonstrating that the Eu(III) ion was effectively sensitized by the intramolecular energy transfer of the ligand. Sensitization of europium(III) by the 3MLCT energy based on an iridium complex-ligand in a d-f bimetallic assembly was previously found to emit red light when irradiated with sunlight. 1-(quinolin-8-yl)butane-1,3-dione, a novel bridging ligand, was synthesized to prepare Eu-Ir complexes with potentially enhanced efficiencies.

Luminescent lanthanide complexes are gaining an increasing amount of interest for their applications in various fields such as OLEDs, immunoassays, analytical sensors, and optical communication. They are promising candidates as light-emitting materials in OLEDs to overcome the difficulty of obtaining pure emission colors with conjugated polymers or small organic molecules. N,N-di(pyridin-2-yl)quinolin-8-amine, a novel blue-emitting ligand, was synthesized to coordinate to europium(III). Experimental studies led to insights of its reactivity with europium acetylacetonate complexes. A new Eu(III) complex based on the diazafluorene ligand was synthesized. A sharp emission band was observed, demonstrating that the Eu(III) ion was effectively sensitized by the intramolecular energy transfer of the ligand. Sensitization of europium(III) by the 3MLCT energy based on an iridium complex-ligand in a d-f bimetallic assembly was previously found to emit red light when irradiated with sunlight. 1-(quinolin-8-yl)butane-1,3-dione, a novel bridging ligand, was synthesized to prepare Eu-Ir complexes with potentially enhanced efficiencies.

Luminescent lanthanide complexes are gaining an increasing amount of interest for their applications in various fields such as OLEDs, immunoassays, analytical sensors, and optical communication. They are promising candidates as light-emitting materials in OLEDs to overcome the difficulty of obtaining pure emission colors with conjugated polymers or small organic molecules. N,N-di(pyridin-2-yl)quinolin-8-amine, a novel blue-emitting ligand, was synthesized to coordinate to europium(III). Experimental studies led to insights of its reactivity with europium acetylacetonate complexes. A new Eu(III) complex based on the diazafluorene ligand was synthesized. A sharp emission band was observed, demonstrating that the Eu(III) ion was effectively sensitized by the intramolecular energy transfer of the ligand. Sensitization of europium(III) by the 3MLCT energy based on an iridium complex-ligand in a d-f bimetallic assembly was previously found to emit red light when irradiated with sunlight. 1-(quinolin-8-yl)butane-1,3-dione, a novel bridging ligand, was synthesized to prepare Eu-Ir complexes with potentially enhanced efficiencies.

Luminescent lanthanide complexes are gaining an increasing amount of interest for their applications in various fields such as OLEDs, immunoassays, analytical sensors, and optical communication. They are promising candidates as light-emitting materials in OLEDs to overcome the difficulty of obtaining pure emission colors with conjugated polymers or small organic molecules. N,N-di(pyridin-2-yl)quinolin-8-amine, a novel blue-emitting ligand, was synthesized to coordinate to europium(III). Experimental studies led to insights of its reactivity with europium acetylacetonate complexes. A new Eu(III) complex based on the diazafluorene ligand was synthesized. A sharp emission band was observed, demonstrating that the Eu(III) ion was effectively sensitized by the intramolecular energy transfer of the ligand. Sensitization of europium(III) by the 3MLCT energy based on an iridium complex-ligand in a d-f bimetallic assembly was previously found to emit red light when irradiated with sunlight. 1-(quinolin-8-yl)butane-1,3-dione, a novel bridging ligand, was synthesized to prepare Eu-Ir complexes with potentially enhanced efficiencies.

The (trivalent) lanthanides exhibit a common sequence of phases upon the application of pressure: hcp → dhcp → fcc → “distorted-fcc”. The “distorted-fcc”’ phase (d-fcc), observed in the light lanthanides is known to be related by geometric distortions to the fcc unit cell, yet the d-fcc phase has been reported to comprise of one or two structures, with no prevailing consensus as to the solution(s). This thesis contains a detailed study of the d-fcc phase of the light lanthanides Pr and Nd. High-pressure angle-dispersive powder-diffraction techniques were employed to systematically study the phases adopted by Pr (up to 25GPa) and Nd (up to 44GPa). Particular attention was paid to solving the d-fcc of each of these elements, the structure of which is very unclear in published work. In Pr, the d-fcc between 7 and 20GPa is shown to comprise of two phases, the solutions of which are shown to be hR24 (R¯3m) and oC16 (Ibam) for the regions 7-14GPa and 14-20GPa, respectively. The pressure dependence of each of these structures over their stability range is presented. Revisions to previously-published volume vs. pressure data are made, with a different value for the volume collapse at the 4f electron delocalisation transition reported. Similarly, the d-fcc phase of Nd, stable over the pressure range 16-40GPa, is studied in detail. Nd differs from Pr by undergoing a further transition, to a hP3 (P63) structure, on pressurisation above 40GPa, before transforming to a α-Uranium phase. The distorted-fcc phase is shown, like that of Pr, to comprise of two phases, hR24 (R¯3m) and oC16 (Ibam) for the pressure regions 16-26GPa and 26-40GPa, respectively. Data on Nd are presented up to the maximum pressure achieved, 44GPa. Data from a preliminary study of La are also presented, along with a brief report on attempts to prepare a single crystal of Pr within a diamond anvil cell, by laser annealing of a powder of Pr.