Philosophiae Doctor - PhD (Chemistry) / Rare earth elements (REEs) have widespread use and importance for industrial applications due to their metallurgical, optical and electronic properties. Several typical hydrometallurgical techniques such as adsorption, chemical precipitation, filtration, ion exchange and solvent extraction techniques have been used for separation and recovery of the rare earth metals from aqueous solutions. Adsorption was recognised as one of the most promising methods due to its simplicity, high efficiency and availability. Many adsorbents are being investigated but there are few adsorbents containing specific functional groups in practical use for REEs recovery. This aim of this study was to develop a nanofibre based adsorbent containing glycolic acid functional groups for the recovery of rare earth metals. Polystyrene (PS) and polyethylene terephthalate (PET) nanofibres were prepared by the electrospinning technique, glycolic acid functional groups were grafted onto the PS or PET nanofibres and the potential of the two modified nanofibre adsorbents for adsorption of Ce3+ or Nd3+ from aqueous solution were investigated and compared. The adsorption experiments were carried out to investigate the effect of different adsorption parameters such as pH, contact time and initial concentration in a batch system in order to achieve the objectives of this research.

Submitted by TIAGO ANDRÉ DENCK COLMAN null (tiago.colman@outlook.com) on 2016-02-22T22:23:17Z No. of bitstreams: 1 tese tiago ok.pdf: 6703785 bytes, checksum: d9b55433cdc5ea86d9680b76ee645eec (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-02-23T16:15:54Z (GMT) No. of bitstreams: 1 colman_tad_dr_araiq.pdf: 6703785 bytes, checksum: d9b55433cdc5ea86d9680b76ee645eec (MD5) / Made available in DSpace on 2016-02-23T16:15:54Z (GMT). No. of bitstreams: 1 colman_tad_dr_araiq.pdf: 6703785 bytes, checksum: d9b55433cdc5ea86d9680b76ee645eec (MD5) Previous issue date: 2016-02-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Foram sintetizados os compostos LnL3•2H2O, sendo que Ln representa os lantanídeos trivalentes (La ao Lu e o ítrio (Y) e o L representa o nicotinato (C6H4NO2--). Os compostos foram sintetizados por adição do ácido nicotínico em carbonatos de lantanídeos e ítrio, sob agitação e aquecimento. A caracterização dos compostos no estado sólido, foi realizada utilizando as técnicas de difratometria de raios X pelo método do pó, complexometria, espectroscopia de absorção na região do infravermelho com transformada de Fourier (FTIR) e pelas técnicas termo analíticas: termogravimetria e calorimetria exploratória diferencial simultâneas (TG-DSC), calorimetria exploratória diferencial (DSC), analise dos gases desprendidos (EGA) por espectroscopia de absorção na região do infravermelho com transformada de Fourier (EGA:TG-FTIR) e termomicroscopia. Os resultados forneceram informações sobre o comportamento térmico, estequiometria dos compostos estudados, cristalinidade, sítios de coordenação e também foi possível identificar os principais produtos gasosos desprendidos durante o aquecimento. / The LnL3•2H2O compounds, where Ln represents the trivalent lanthanides (La to Lu) and yttrium (Y), and L represents nicotinate (C6H4NO2--) were synthesized. The synthesis was perfomed by addition of nicotinic acid lanthanides and yttrium carbonates, with stirring and heating. The characterization of the compounds in the solid state was carried out using the techniques of X-ray diffraction powder pattern, complexometry, infrared spectroscopy (FTIR) and by thermoanalytical techniques: simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), differential scanning calorimetry (DSC), evolved gas analysises (EGA) by infrared spectroscopy (EGA: TG-FTIR) and thermalmicroscopy.The results provided information on the thermal behavior of the studied as compounds stoichiometry, crystallinity, coordination sites. It was also possible to identify the main gaseous products evolued during heating. / CNPq: 141952/2013-0

Submitted by ELAINE CRISTINA MUNIZ null (elainecris7@yahoo.com.br) on 2016-03-11T12:09:12Z No. of bitstreams: 1 ELAINE CRISTINA MUNIZ-tese.pdf: 10917322 bytes, checksum: bd6553f5a382221f4d18db6600416bcb (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-03-14T18:09:48Z (GMT) No. of bitstreams: 1 muniz_ec_dr_araiq_par.pdf: 726928 bytes, checksum: c405502c64aca6bda28f96dbbfbca30f (MD5) / Made available in DSpace on 2016-03-14T18:09:48Z (GMT). No. of bitstreams: 1 muniz_ec_dr_araiq_par.pdf: 726928 bytes, checksum: c405502c64aca6bda28f96dbbfbca30f (MD5) Previous issue date: 2016-02-26 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Materiais luminescentes despertam grande interesse nas pesquisas devido à variedade de aplicações, podendo ser empregados em displays eletrônicos, lâmpadas fluorescentes e diodos emissores de luz, por exemplo. Neste contexto, os íons lantanídeos trivalentes são destaque pois apresentam propriedades luminescentes únicas como alta pureza de cor, tempo de vida de nano a milissegundos e linhas de emissão definidas e estreitas provenientes de transições intraconfiguracionais 4f-4f. No entanto, devida à natureza proibida dessas transições, os íons lantanídeos apresentam baixa absortividade molar. Para suprir essa deficiência, pode ser realizada a coordenação destes íons com bons grupos cromóforos capazes de transferir energia para os níveis 4f dos lantanídeos. Outra estratégia para melhorar as propriedades luminescentes de materiais é através da combinação e/ou dopagem utilizando diferentes lantanídeos, o que pode resultar na emissão de ambos os íons ou na emissão preferencial de um deles por meio de processos de transferência de energia. Espécies bimetálicas heteronucleares e polímeros de coordenação porosos (Metal Organic Frameworks, MOFs) se destacam neste cenário. Neste trabalho foram estudadas quatro séries de compostos bimetálicos heteronucleares utilizando succinato de sódio e ácido 3,5-dicarbóxipirazolico como ligantes e variando a razão entre dois íons lantanídeos distintos, Gd3+:Eu3+, Gd3+:Tb3+, Dy3+:Eu3+ e Eu3+:Tb3+. Os compostos obtidos foram caracterizados por difração de raios X de monocristal e de pó, espectroscopia na região do IV, análise térmica, espectroscopia de reflectância difusa, espectroscopia de fotoluminescência com excitação UV, luminescência com excitação por raios X e microscopia eletrônica de varredura associada à espectroscopia por energia dispersiva. Os complexos apresentaram interessantes propriedades luminescentes. Para as séries de compostos contendo íons Gd3+, quanto maior a quantidade de Gd3+, maior a intensidade da banda relativa à transferência de carga do ligante para o metal, indicando que os íons Gd3+ possuem um papel importante no mecanismo de transferência de energia do ligante para os lantanídeos emissores. Foram calculados os parâmetros de intensidade, as taxas de decaimento radiativo e não-radiativo e a eficiência quântica para a série Gd3+:Eu3+, que apresentaram baixa eficiência quântica, devido principalmente à supressão da luminescência pelas moléculas de água presente na estrutura. Os compostos da série Dy3+:Eu3+ não apresentam transferência de energia entre os lantanídeos e só foi possível observar a emissão dos dois íons ao mesmo tempo quando a excitação é realizada no ligante ou quando se utilizou raios X para a excitação. Já na série Eu3+:Tb3+, observou-se transferência de energia apenas dos íons Tb3+ para os íons Eu3+. O oposto não foi verificado. Os espectros de emissão dessa série registrados em diferentes temperaturas mostram que os compostos Eu3+:Tb3+ possuem potencialidade para aplicação como termômetro molecular na faixa de temperatura entre -80 e 25°C. Foram realizadas três sínteses diferentes para preparação dos MOFs. Os compostos obtidos apresentam intensidade de emissão e eficiência quântica elevadas. Além disso, a estabilidade térmica dos compostos é evidência de que os compostos obtidos podem ser de fato MOFs. / Luminescent materials attract interest in research due to the diversity of applications. These materials can be used at electronic displays, fluorescent lamps and light emitting diodes, for example. In this context, trivalent lanthanide ions are interesting because of their unique luminescent properties like high color purity, nano to milliseconds lifetime and narrow emission lines from 4f-4f transitions. However, because of the nature of forbidden 4f-4f transitions, lanthanide ions have low molar absorptivity. To supply this deficiency, the lanthanide ions can be coordinated to chromophore groups, capable of transfer energy to the 4f levels of lanthanides. It is also possible to improve the luminescent properties of materials by combining different lanthanides, which can result in the emission of both ions or in the preferential emission of one of them by energy transfer processes. Bimetallic heteronuclear complexes and metal organic frameworks (MOFs) are interesting in this context. In this work, four bimetallic heteronuclear compounds series with sodium succinate and 3,5- dicarboxypyrazolate ligands were prepared with different lanthanides ratio, Gd3+:Eu3+ , Gd3+:Tb3+, Dy3+:Eu3+ e Eu3+:Tb3+ . The compounds were characterized by single crystal and powder X-ray diffraction, Fourier transform infrared spectroscopy, thermal analysis, UV-Vis spectroscopy, photoluminescence spectroscopy, X-ray excited optical luminescence and field emission gun-scanning electron microscopy, with energy dispersive X-ray spectroscopy. The complexes present interesting luminescent properties. In Gd3+ compounds series, by increasing the amount of Gd3+ ions in the sample, the intensity of the relative charge transfer band also increases, indicating that the Gd3+ ions play an important role in the energy transfer mechanism from ligands to the lanthanides. The intensity parameters, the radiative and non-radiative decay rates and the quantum efficiency were calculated to Gd3+:Eu3+ series, which showed low quantum efficiency due to luminescence quenching by water molecules in the structure. The Dy3+:Eu3+ compounds does not show energy transfer between the lanthanides ions and the emission from both ions was observed simultaneously only under excitation at the ligand absorption or under X-rays excitation. In the Eu3+:Tb3+ series, the energy transfer was observed only from Tb3+ ions to the Eu3+ ions. The opposite was not verified. The emission spectra of the Eu3+:Tb3+ compound recorded at different temperatures show that this series compounds present potential to be applied as molecular thermometer in the range of -80 to 25 °C. Three different syntheses were performed to prepare MOFs. The obtained compounds exhibit high emission intensity and good quantum efficiency. Furthermore, the thermal stability of the compounds is evidence to propose that the obtained compounds is indeed MOFs. / CNPq: 141262/2012-5

Submitted by Maike Costa (maiksebas@gmail.com) on 2017-06-28T12:38:08Z No. of bitstreams: 1 arquivototal.pdf: 2848315 bytes, checksum: 889dad8fe5cef6b4c28b622bd45da5cb (MD5) / Made available in DSpace on 2017-06-28T12:38:08Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2848315 bytes, checksum: 889dad8fe5cef6b4c28b622bd45da5cb (MD5) Previous issue date: 2016-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Homonuclear complexes LnCitnH2O (Ln3+ = Eu3+, Tb3+ and Gd3+) were synthesized by stoichiometric addition of the respective aqueous solutions of the Ln3+ ions under the form nitrate and sodium citrate solution (Na3Cit) at a ratio of 1:1. A complex of formula Bi6O4(OH)4Cit2.2H2O, (M1), was synthesized similarly to the homonuclear complexes Ln3+, wherein the composition obtained was not compatible with the stoichiometry of the starting reactants, i.e., the stoichiometric bismuth/citrate ratio of 1:1. Other bismuth complex, with minima formula BiCit2H2O, (M2), was synthesized by reaction of Na3Cit with Bi(NO3)3 and phen, from the stoichiometric ratio 1:1:1, i.e., citrate, Bi3+ and phen. The complex EuCit.1/2(phen).2H2O (phen = 1,10-phenanthroline) was obtained by reaction between Na3Cit, Eu(NO3)3 and phen with a stoichiometry of the starting reactants in the ratio 1:1:1. Complexes bismuth and lanthanide, heteronucleares, were also synthesized in the ratio 1:1:2, from their respective nitrate salts of Bi3+ and Ln3+ and of the Na3Cit salt. All of these materials were characterized using: atomic graphite furnace absorption spectrophotometry, elemental analysis (CHN), (except for complexes M1 and M2), infrared (IR) spectroscopy and thermal analysis (TG-DTA-DTG). For the EuCit.1/2(phen).2H2O complex, luminescence spectroscopy was also used, which showed high luminescent intensity when irradiated with light of wavelength 350 nm. From the quantitative data of the graphite furnace, elemental analysis (CHN) and thermal analysis techniques, the chemical composition of each complex was suggested and by infrared, coordination forms of the ligands Cit and phen to ions metallics were found. For the heteronuclear complexes, the results of all these techniques indicate structures of the types [LnBi2Cit2.3H2O](H2O)3 ( Ln = Eu3+ and Gd3+ ) and [BiTbCit.2H2O](H2O)3. / Complexos homonucleares LnCit.nH2O (Ln3+ = Eu3+, Tb3+ e de Gd3+ ( n= 1 - 3)) foram sintetizados por adição estequiométrica das respectivas soluções aquosas dos íons de Ln3+, sob a forma nitrato, e da solução de citrato de sódio (Na3Cit), sendo a proporção usada referente às soluções dos reagentes de 1:1. Complexos de bismuto e lantanídeo, heteronucleares, também foram sintetizados a partir dos respectivos sais de nitrato de Bi3+ e Ln3+ e do sal de Na3Cit agora na proporção 1:1:2. Um complexo de fórmula Bi6O4(OH)4Cit2.2H2O, (M1), foi sintetizado de modo semelhante aos dos complexos homonucleares Ln3+, porém, a composição obtida não foi compatível com a estequiometria dos reagentes de partida, ou seja, estequiométrica de 1:1, bismuto / citrato. Outro complexo de bismuto, com fórmula mínima de BiCit.2H2O, (M2), foi sintetizado pela reação de Na3Cit com Bi(NO3)3 e fen, a partir da razão molar 1:1:1, isto é, citrato, ion de bismuto e fen. Também um complexo de európio com composição EuCit.1/2(fen).2H2O (fen = 1,10-fenantrolina) foi obtido pela reação entre Na3Cit, Eu(NO3)3 e fen com uma estequiometria dos reagentes de partida também na proporção de 1:1:1. Todos estes materiais foram caracterizados por: espectrofotometria de absorção utilizando forno de grafite, análise elementar (CHN), (com exceção dos complexos M1 e M2), espectroscopia vibracional na região do infravermelho (FTIR) e análise térmica (TG-DTA-DTG). Para o complexo EuCit.1/2(fen).2H2O espectroscopia de luminescência foi também usada, tendo o mesmo mostrado alta intensidade luminescente quando irradiado com luz de comprimento de onda de 350 nm. A partir dos dados quantitativos de forno de grafite, análise elementar (CHN) e técnicas de análise térmica, a composição química de cada complexo foi sugerida e pelos espectros de infravermelho, as formas de coordenação dos ligantes Cit e fen aos íons metálicos foram também indicadas. Para os complexos heteronucleares, os resultados das três primeiras técnicas indicam estruturas dos tipos [LnBi2Cit2.3H2O](H2O)3 ( Ln = Eu3+ e Gd3+) e [BiTbCit.2H2O](H2O)3.

Les molécules-aimants ou Single–Molécule Magnets (SMM) ont attiré une attention croissante au cours des dernières années en raison de leur potentiel attrayant en tant que dispositifs de stockage magnétique à haute densité. Beaucoup d'efforts ont été faits pour améliorer la performance magnétique de ces molécules à l’aide des techniques de chimie de coordination.Dans cette thèse, le travail est organisé en deux parties principales. La première partie est constituée des chapitres 2 et 3 qui se concentrent principalement sur les familles Lanthanide-radicaux zéro- et mono-dimensionnelles. La deuxième partie contient les chapitres 4 et 5, ou des ligands diamagnétiques sont utilisés afin concevoir des matériaux multifonctionnels.Dans la première partie, neuf radicaux TEMPO-R (R représente le substituant) sont utilisés. Leur structure cristalline, ainsi que leurs propriétés magnétiques ont été caractérisées. Dans le chapitre 2, quatre radicaux (TEMPO-OCH3, TEMPO-NH2 TEMPO-Acetamido et TEMPO-OCH2CCH) sont utilisés pour synthétiser des complexes zéro-dimensionnels, dont trois présentent des propriétés de SMM. Dans le cas particulier de TEMPO-OCH3, un très rare comportement de SMM avec lanthanides légers est observé (CeIII, PrIII et NdIII). La première SMM à base de PrIII est ainsi reportée. Dans le chapitre 3, l'objectif est de concevoir des SMM organisés mono-dimensionnellement dans l’empilement cristallin. Cinq autres radicaux sont utilisés: TEMPO-Méthacrylate, TEMPO-OCOPh, TEMPO-oxo, TEMPO-OH et TEMPO-CN. Parmi toutes les chaînes obtenues, [Pr(hfac)3(H2O)(TEMPO-OH)]n (17), [Dy(hfac)3-TEMPO-OH)]n (18) et [Tb(hfac)TEMPO-CN)]n (22) sont identifiés comme SMM. 22 présente la relaxation magnétique la plus lente parmi tous les SMM 4f-2p obtenues dans cette thèse, avec une d'hystérèse magnétique à basse température. Son analogue à base GdIII (23) présente une des plus grandes valeurs d'échange dans les composés de Gd-2p. Enfin un très rare exemple de réseau bidimensionnel 4f-2p de formule [(Ce(hfac)3)3(Oxo-TEMPO)4]n (15) est obtenu. Dans la deuxième partie, une chaine de dimère est obtenue par réaction d'un ligand carboxylique photo-commutable avec des sels d’ions LnIII. La photo-sensibilité du ligand sous irradiation UV a été testée et des mesures magnétiques en solution ont été entreprises. En outre, un composé de type Metal-Organic-Framework (MOF) présentant un comportement de SMM de {[Dy2(o-PDA)3(H2O)2]2H2O}n (28) a été conçu et caractérisé. Une interaction ferromagnétique Ln-Ln a été observée dans ce MOF-SMM et le dopage diamagnétique démontre que, contrairement à ce qui est observé sur [Ln(AZO)3(DMSO)(H2O)]2•4DMSO, cette interaction favorise le comportement de SMM. / Single-molecule-magnet (SMM) has attracted increasing attention in recent years due to their appealing potential for high-density storage devices. Much effort has been made to improve the magnetic performance through flexible coordination chemistry strategy.In this thesis, the work is organized in two main parts. The first part is constituted of chapter 2 and chapter 3, primarily focus on the Ln-Radical families aiming at designing zero-dimensional and one-dimensional single-molecule-magnet (SMM). The second part contains chapter 4 and chapter 5, in which the ligands are replaced by diamagnetic ones for the purpose of designing the multifunctional materials.In the first part, nine TEMPO-R (R represents the substituent) radicals are employed to construct zero-dimensional and one-dimensional complexes. These kinds of compounds were prepared by reactions in the dichloromethane/n-heptane co-solvents between the precursor [Ln(hfac)3(H2O)2] and TEMPO radicals. Subsequently their molecular structure as well as magnetic properties have been characterized and described. In chapter 2, four radicals (TEMPO-OCH3, TEMPO-NH2 TEMPO-Acetamido and TEMPO-OCH2CCH) are used to synthesize monometallic or dimetallic complexes, among which three are successful to construct the SMM. For the special case of TEMPO-OCH3 a rare light lanthanide ions (CeIII, PrIII and NdIII) SMM behavior is reported. The PrIII derivative is the first PrIII-based SMM ever reported. In chapter 3, the target is to design SMM in one dimension by using another five radicals: TEMPO-Methacrylate, TEMPO-OCOPh, TEMPO-oxo, TEMPO-OH and TEMPO-CN. Among all the chains, [Pr(hfac)3(H2O)(TEMPO-OH)]n (17), [Dy(hfac)3-TEMPO-OH)]n (18) and [Tb(hfac)3(TEMPO-CN)]n (22) are identified as chains of SMM. 22 exhibits the slowest magnetic relaxation among all the 4f-2p SMMs obtained in this thesis, with a small opening of magnetic hysteresis. Its analogue of [Gd(hfac)3(TEMPO-CN)]n (23) even exhibits one of the largest exchange values in Gd-2p compounds. Last a very rare example of bidimensional 4f-2p network of formula [(Ce(hfac)3)3(Oxo-TEMPO)4]n (15) is obtained.In chapter 4, the salt of a photo-switchable carboxylic ligand was reacted with LnIII ions to afford a chain-like arrangement of dinuclear complexes of formula [Ln(AZO)3(DMSO)(H2O)]2•4DMSO. Photo-sensitivity of the ligand under the irradiation of UV has been tested together with magnetic measurements in solution. In chapter 5, a Metal-Organic-Framework (MOF) (28) has been designed and characterized. Ln-Ln ferromagnetic interaction has been observed and diamagnetic doping highlight that, contrary to what observed on [Ln(AZO)3(DMSO)(H2O)]2•4DMSO, this interaction promote SMM behavior in a so-called MOF-SMM.

This work describes an investigation into the solution-phase binding of anionic guests by bimacrocyclic lanthanide complexes. It outlines the preparation of different classes of complexes bearing two metallic domains, and the effects of association on both the complex and the guest. Chapter one provides a cursory introduction to the fundamental properties of the lanthanides with a focus on luminescence. A brief literature review is given on the use of emissive lanthanide probes for the sensing of analytes. Chapter two concerns the preparation and properties of a series of binuclear complexes in which the two centres are linked with a short spacer group, with the aim of selectively sequestering small anions such as the halides in solution. The concept of luminescence titration will be introduced and then used to assess the binding parameters of a selection of guests. Chapter three describes a related class of ditopic lanthanide complexes in which the two metal centres are separated by a semi-rigid butyne linking group. Luminescence studies are again used to evaluate the binding constants of homologous series of dianions to ascertain how the size, geometry and functionalization of the anionic guest impacts on binding. Chapter four explores the coordination of phosphate species and assesses the ability to bind biologically significant phosphates of some of the complexes from Chapter 3. Chapter five details an investigation into the effects on guest-selectivity of further lengthening the linking unit which separates the two macrocyclic binding domains. Chapter six summarises the work done throughout the thesis and draws some overarching conclusions, as well as highlighting areas for further study. Chapter seven describes the experimental procedures.

Les électrons 4f sont fortement localisés et leurs répulsions coulombiennes intersites sont évaluées comme plus larges que leurs largeurs de bande. Parmi tous les lanthanides, le cérium est particulièrement fascinant. Ceci s'explique par la forte hybridation avec les bandes 6s-6p-5d qui se situent toutes au niveau de Fermi. L'origine de l'effondrement du volume lors de la transition isostructurale γ-α est une énigme difficile à résoudre depuis sa découverte en 1927. Expérimentalement, la transition γ-α se réalise seulement à température finie. Récemment, des mesures très précises de diffraction aux rayons X ont confirmé le caractère isotructural (groupe Fm-3m) du premier ordre. À partir des premiers principes, nous avons caractérisé la transition de phase γ-α du cérium par une méthode utilisant une fonction d'onde Jastrow corrélée qui minimise l'énergie variationnelle de l'hamiltonien relativiste scalaire. L'ansatz variationnel traite les corrélations de manière non-perturbative et reproduit les propriétés des deux phases en accord avec l'expérience. Cela prouve que même à température nulle, la transition est toujours du premier ordre avec des paramètres ab initio qui sont sans aucun doute reliés aux mesures obtenues par l'expérience à température finie T. Nous montrons que la transition est liée à un réarrangement complexe de la structure électronique qui affecte en même temps la localisation des orbitales t1u (leur répulsion coulombienne) et le caractère de la liaison chimique. / The 4f electrons are strongly localized and their on-site Coulomb repulsion is large compared to bandwidth. Among all lanthanides, cerium is particularly fascinating, due to the strong hybridization with the 6s-6p-5d bands, all present at the Fermi level. The origin of the cerium volume collapse along the isostructural γ-α transition has been a puzzle since its discovery in 1927. Experimentally, pure cerium undergoes the γ-α transition always at finite temperature T. Recently, very accurate X-ray diffraction measurements undoubtedly confirmed the first-order Fm-3m isostructural character of the transition. The first-order line extrapolates to zero-T at negative pressures. The cerium γ-α phase transition is characterized by means of a many-body Jastrow-correlated wave function, which minimizes the variational energy of the first-principles scalar-relativistic Hamiltonian, and includes correlation effects in a non-perturbative way. Our variational ansatz reproduces the structural properties of the two phases, and proves that even at temperature T = 0 K the system undergoes a first order transition, with ab-initio parameters which are seamlessly connected to the ones measured by experiment at finite T. We show that the transition is related to a complex rearrangement of the electronic structure, with key role played by the localisation of t1u orbitals, which tunes the Coulomb repulsion, and the character of the chemical bond.

Lanthanide(III) and actinide complexes with the N-donor extractants which are proposed for se in next generation separation processes, CyMe4-BTPhen and CyMe4-BTBP, have been synthesised and characterised in idealised synthetic and real extraction conditions. Next generation spent nuclear fuel reprocessing is necessary in order to reduce the longevity of activity (from 100,000’s to 100-1,000’s years) through re-use as fuel in GenIV reactor programs. The N donor extractants have been previously shown to preferentially extract the trivalent An ions over the Ln ions in biphasic acidic extraction processes, a necessary task due to the large neutron capture crosssections of the lanthanides, and the reasons behind this selectivity have been investigated here. Proposed processes that use these extractants are called SANEX and GANEX. The SANEX process is undertaken after a PUREX-style process where only the trivalent minor actinides and the lanthanides are present during the separation. Whereas, in the GANEX process the organic phase contains the N-donor molecule and another extractant, such as TBP, with the aqueous phase containing the entire An series in various oxidation states. Speciation of the Ln3+ ions with the N-donor molecules has been shown to be dominated by 1:2 (M:L) complexes in the bulk organic phase post extraction and coordination is completed by a small ligand, either H2O or NO3-. Spectrophotometric titration yielded logβ values for the 1:2 (M:L) complexes of Pr3+, Eu3+ and Tb3+ nitrate salts. In all cases it was shown that the CyMe4-BTPhen molecule has a greater affinity than the CyMe4-BTBP molecule for the Ln3+ ions, as expected given the ‘locked’ design of CyMe4-BTPhen. The uranyl ion was shown to only form 1:1 (M:L) complexes in solution with the N-donor molecules but structural characterisation showed it to also form 2:1 (M:L) complexes with the metal ions bridged by a peroxide anion. The formation of this species was found to require a protic solvent, light and molecular dioxygen. Again, binding was shown, by spectrophotometric titration, to be stronger with CyMe4-BTPhen than CyMe4-BTBP.The speciation of the tetravalent An ions, Pu4+ and Th4+ was studied using 1H NMR and X-ray absorption spectroscopy in GANEX style conditions. When the organic phase contains TBP and the N donor extractants, complexation is completed by TBP in the post extraction organic phase and the extraction of Th4+ is exclusively completed by TBP but by both extractants for Pu4+. In both cases, the major bulk species was identified as Pu/Th(NO3)4.3TBP, although complexes of the N donor extractants and the An4+ have been observed in idealised conditions, in both 1:1 and 1:2 (M:L) stoichiometries, depending on the solution composition. U4+ was shown to form a variety of complexes of a myriad of M:L stoichiometries.

Ce mémoire est consacré à l'élaboration, au greffage chimique de macrocycles azotés sur des surfaces, le développement des procédés d'élaboration de surfaces sensibles aux ions, l'évaluation de leurs propriétés et la réalisation de prototypes de capteurs chimiques sensibles aux ions. Les macrocycles azotés sont des cyclames sensibles aux ions de métaux de transition et des terpyridines sensibles aux lanthanides. Un capteur sensible à l'ion Fer (III) est réalisé par fonctionnalisation d'un ISFET et de structures de nitrure de silicium/silicium au moyen du greffage de macrocycles azotés de type cyclames sur la surface du dispositif. Un agent de couplage poly(méthylhydrosiloxane) (PMHS) permet cette immobilisation avec une grande efficacité. L'immobilisation d'un dérivé du cyclame (naphtyl-cyclam) sur des surfaces d'or a permis la préparation de capteurs chimiques sensibles aux ions. Les molécules de cyclame ont été déposées sur des électrodes en or par des interactions fortes entre le groupe de naphtyle et la surface d'or. Le film obtenu a été caractérisé en termes de composition, morphologie et propriétés électriques. La conductivité protonique du film naphtyl-cyclam a été mise en évidence par la spectroscopie d'impédance électrochimique (EIS) et la voltampérométrie cyclique (CV). Nous avons montré que l'immobilisation de dérivé de phényl-terpyridine sur des surfaces d'or a permis la préparation des capteurs chimiques sensibles aux ions Gadolinium (III). Les molécules de terpyridine ont été auto-assemblées sur des électrodes en or par des interactions fortes (greffage chimique) avec groupement thiol terminal. Les propriétés électriques de ces interfaces films sensibles/électrolyte sont décrites et des modèles théoriques sont proposés d'après les résultats expérimentaux obtenus par la spectroscopie d'impédance électrochimique / This dissertation is devoted to the elaboration, the chemical grafting of aminated macrocycles on surfaces, the development of elaboration processes of surfaces sensitive to the ions, the evaluation of their properties and the fabrication of prototypes of chemical sensors sensitive to the ions. The aminated macrocycles are cyclames, sensitive to transition metal ions and terpyridines sensitive to lanthanides. A chemical sensor sensitive to iron (III) ion is fabricated by means of the functionalization of an ISFET and of silicon nitride/silicon structures through grafting of aminated macrocycles of the cyclam type on to the surface of the device. The coupling agent poly(methylhydrosiloxane) (PMHS) allows such an immobilization with a high efficiency. The immobilization of a derivative of cyclam (naphtyl-cyclam) on gold surfaces allowed the preparation of chemical sensors sensitive to the ions. The molecule of cyclam was deposited on gold electrodes by strong interactions between the naphtyl group and the gold surface. The film obtained was characterized in terms of composition, morphology and electrical properties. The proton conductivity of the N-MNC film was brought out, for the first time, by electrochemical impedance spectroscopy (EIS) and by cyclic voltammetry (CV). We showed that the immobilization of the phenyl-terpyridine derived on gold surfaces allowed the preparation of the chemical sensors sensitive to gadolinium (III) ions. The molecules of terpyridine were self-assembled on gold electrodes by strong interactions (chemical grafting) with a final thiol group. The electrical properties of these sensitive films/electrolyte are described and theoretical models are proposed from the experimental results obtained by the electrochemical impedance spectroscopy

Les lanthanides sont de plus en plus étudiés par la communauté scientifique et leur utilisation au sein de dispositifs grand public ne fait que croître. Ces éléments sont en effet connus pour présenter des propriétés magnétiques et de luminescence remarquables. Ils sont alors particulièrement efficaces pour la création de molécules aimants ou de matériaux luminophores. Dans ces travaux de thèse, la synthèse, la cristallogenèse et les caractérisations magnétiques et photo-physiques de nouveaux complexes associant lanthanides et molécules organiques photo-actives sont étudiées. Ces dernières possèdent une conformation « trans » et « cis » et il est possible, grâce à un stimulus lumineux (irradiation UV), de passer de l'une à l'autre. Cette photo-isomérisation induit un changement des propriétés du complexe au sein duquel elles sont présentes. Dans la première partie, quatre nouveaux complexes à base de DyIII, EuIII, TbIII et SmIII sont présentés. Ils sont obtenus grâce à l'association de précurseurs de terres rares et d'une molécule organique dérivée de stilbène : la 4-styrylpyridine. Une forte modulation des propriétés optiques de ces composés induite par l'isomérisation du ligand est observée. Il est mis en évidence que celle-ci a un impact notable sur les propriétés de luminescence des composés et sur leur couleur émise. Dans un second temps, l'influence de cette isomérisation sur les propriétés magnétiques du complexe à base de DyIII est étudiée. La deuxième partie consiste en l'élargissement de l'étude à des molécules photo-actives voisines dans le but de caractériser l'influence du changement de certains groupements chimiques sur les propriétés de photo-isomérisation. Un dérivé de 4-styrylpyridine comportant un groupement diméthyle-amino a ainsi été associé avec un ion DyIII. Un nouveau complexe a été obtenu et ses propriétés magnétiques à l'état solide et en solution étudiées. Parallèlement, l'utilisation d'une nouvelle molécule comportant un groupement diéthyle-amino ainsi qu'une partie azobenzène a donné lieu à l'obtention de deux nouveaux composés à base de DyIII et de TbIII. L'impact de l'isomérisation de ce ligand sur les propriétés luminescentes du complexe à base de TbIII et sur les propriétés magnétiques du complexe à base de DyIII a ensuite été étudié. Dans une troisième partie, les perspectives d'évolution du sujet sont présentées. Une première stratégie consiste à utiliser des solvants moins protonant que le chloroforme afin d'observer une photo-isomérisation plus robuste. Une deuxième stratégie est d'utiliser un ligand magnétique photocommutable. Un radical de la famille des nitronyl nitroxide substitué par un groupement stilbène a ainsi été synthétisé et coordiné à des ions DyIII et TbIII. Leur étude photophysique est commentée. / Lanthanides are more and more studied by the scientific community and their use in devices and operating materials is exploding. These elements are indeed known to exhibit remarkable magnetic and luminescent properties. They are indeed particularly effective for the creation of singles molecule magnets or light emissive materials. In this thesis work, the synthesis, the crystal growth and the magnetic and photo-physical characterizations of new complexes that associates lanthanides and photo-active organic molecules are studied. The latter possess a " trans " and "cis" conformation and it is possible, thanks to a bright UV irradiation stimulus, to switch from one to the other one. This photo-isomerization leads to a modification of the properties of the complex in which they are part of. In the first part, four new complexes with DyIII, EuIII, TbIII and SmIII are presented. They are obtained thanks to the association of precursors of lanthanides and an organic molecule from the stilbene family: the 4-styrylpyridine. A strong modulation of the optical properties of these compounds led by the isomerization of the ligand is observed. It is highlighted that this one has a notable impact on the luminescent properties of these four compounds and on their color emission. Then, the influence of this isomerization on the magnetic properties of the complex with DyIII is studied. The second part consists of the extension of the study in lookalike photo-active molecules. The aim of this work is to characterize the influence of the change of a given chemical group on the photo-isomerization properties. A ligand that is closely related to 4-styrylpyridine containing a dimethyl-amino group, is associated with a DyIII ion. A new complex is obtained and its magnetic properties in the solid state and in solution are studied. Besides, the use of a new molecule containing a diethyl-amino group as well as an azobenzene part gave rise to two new compounds with DyIII and with TbIII. The impact of the isomerization of this ligand on the luminescent properties of the complex with TbIII and on the magnetic properties of the complex with DyIII is then studied. In the third part, the perspectives of evolution of the subject are presented. A first strategy consists is to use less protonatings solvents than the chloroform to observe a stronger photo-isomerization. The second strategy is to use a photo-switching magnetic ligand. A radical of the nitronyl nitroxide family substituted by a stilbene group was synthesized and coordinated to DyIII and TbIII ions. Their photophysical study is commented.