Les édifices multi-porphyriniques retiennent de plus en plus l'attention des chercheurs et leur compréhension n'a cessé de croître ces dernières années en raison de leur vaste domaine d'application, que ce soit pour l'élaboration de complexes collecteurs d'énergie lumineuse, pour la construction de fils moléculaires photoniques ou électroniques ainsi que pour la formation de complexes supramoléculaires originaux.<br />Dans l'optique de synthétiser des pinces bis-porphyriniques capables de former des complexes supramoléculaires stables avec des bases bidentates de tailles variées, nous avons synthétisé plusieurs architectures moléculaires de type bis- et tris-porphyrines dans lesquelles les chromophores sont liés entre eux par des espaceurs nucléosidiques flexibles dérivés de l'uridine. Nous avons donc fait varier les positions d'ancrage des deux porphyrines sur l'uridine en accrochant soit les deux porphyrines en des positions différentes du sucre, soit en greffant un chromophore sur le ribose et l'autre sur l'uracile. <br />La caractérisation par spectroscopie UV-visible de l'ensemble des architectures moléculaires nous a permis d'observer l'existence d'interactions électroniques entre les différents chromophores au sein de ces composés. Pour deux des trois dimères ainsi que pour les trimères, l'espaceur nucléosidique bloque la conformation de ces molécules sous la forme de pinces comportant une cavité pré-organisée. Ainsi, la complexation de bases bidentates de tailles variées a été suivie par spectroscopie UV-visible, et des constantes d'association supérieures de 1,5 à 2 ordres de grandeur par rapport à la complexation des mêmes bases par une mono-porphyrine ont été trouvées. La pré-organisation des cavités bis-porphyriniques augmente donc la stabilité des complexes supramoléculaires de type hôte/récepteurs formés. En outre, l'ajustement de la cavité à la taille de l'hôte complexé a pu être démontré. Un piégeage efficace de la luminescence de la porphyrine de Zn(II) a également été observé au sein des deux dimères porteurs à la fois d'une porphyrine de Zn(II) et d'une porphyrine base-libre, et attribué à un transfert d'énergie ayant lieu vers la porphyrine base-libre.<br />Enfin, ces espaceurs nucléosidiques offrent la possibilité d'établir des liaisons hydrogène avec un synthon complémentaire de l'uracile fonctionnalisé par une porphyrine ou deux, et ainsi d'augmenter le nombre de chromophores collecteurs de photons.

Bien que présents dans l'organisme en quantités infinitésimales, les métaux de transition jouent un rôle physiologique essentiel. On les trouve généralement sous forme de chélates avec des coordinats biologiques de masse molaire élevée dont l'étude est particulièrement difficile. Il est cependant possible de modéliser les sites actifs de ces macromolécules à l'aide de petites molécules plus faciles à étudier. Nous avons synthétisé des pseudo-peptides à base d'histamine pour simuler les sites de coordination de protéines telles que la sérum albumine. Ces peptidoamines sont également intéressantes du fait de leur activité antioxydante. L'étude des propriétés complexantes de ces molécules vis-à-vis du Cu(II) et du Ni(II) a permis de mettre en évidence une variété de complexes parfois très différents par leur nature et leur stabilité. À partir de ces résultats, nous avons proposé la synthèse de nouveaux tensioactifs possédant des propriétés complexantes par greffage d'un chaîne hydrophobe sur des peptides contenant l'histidine. Les têtes polaires correspondent aux pseudo-peptides peptides ß-alanyl-histidine et glycyl-glycyl-histidine. Les concentrations micellaires critiques ont été déterminées par tensiométrie et fluorimétrie et les diagrammes de phase binaires ont été tracés. Les propriétés complexantes ont été démontrées et les diagrammes de répartition de espèces ont été déterminés à partir de molécules modèles à courte chaîne hydrophobe. Enfin des tensioactifs trimodulaires ont été préparés en greffant sur les molécules précédentes une partie de type polyoxyéthylène, pour augmenter l'hydrophilie.

Addition of alkalinity to acid mine drainage (AMD) results in the neutralisation of acidity and precipitation of dissolved metals as insoluble hydroxides. Two aspects of the current AMD treatment practice at the Stockton Mine could be enhanced. Firstly, residual water quality may be poor due to unreacted alkalinity reagents, particularly CaCO3, resulting in poor water clarity and elevated suspended solids (SS). Secondly, neutralisation to circum-neutral pH may not avoid the discharge of residual metals (Ni and Zn) due to incomplete adsorption and hydroxide precipitation. The aim of this project was to enhance the conventional neutralisation of AMD through addition of humic substances (HS) to reduce residual SS and trace metal concentrations. Humic substances are organically derived and have a high molecular weight. Functional groups on the surface of HS are capable of binding dissolved metals, forming HS-metal complexes. Incorporation of HS complexed metals into settling floc could result in increased metal removal from the dissolved phase. Modified jar testing was used to investigate the effects of HS addition before, after and during (pH 4.5) neutralisation of AMD in two treatment scenarios at the Stockton Mine; the Blackwater Treatment Plant (BTP) using NaOH and Ca(OH)2 and the Mangatini Stream-sump System (MSS) using CaCO3. Supernatant samples collected during the sedimentation period were analysed for basic water quality parameters (turbidity and suspended solids) and dissolved (< 0.45 µm) metal concentrations. The addition of HS to the BTP process before (pH 2.8) and during (pH 4.5) neutralisation resulted in HS precipitation. Precipitated HS subsequently acted as a nucleation site, triggering flocculation of precipitating metal hydroxides, resulting in low turbidity and suspended solids (SS) of less than 2 NTU and 5 mg/L, respectively. The addition of HS after neutralisation (pH 7) did not result in HS precipitation. Intermolecular bridging of HS by the divalent Ca resulted in incorporation of HS into floc when neutralised by Ca(OH)2, resulting in low turbidity and SS. However, in NaOH neutralised conditions, the monovalent Na was unable to bridge HS molecules, resulting in HS remaining dissolved and contributing to elevated turbidity and SS of up to 24.4 NTU and 18.4, respectively. The neutralisation efficiency of CaCO3 is relatively low, thus approximately 1000 mg/L CaCO3 remained unreacted in MSS scenarios, resulting in elevated turbidity and SS. When added after neutralisation, dissolved Solid Energy Humic Acid (SEHA) facilitated flocculation of residual CaCO3 SS, resulting in an up to 75% lower suspended solids than CaCO3 neutralisation alone conditions. Although the results are good, the efficiency of SEHA as a polymer compared unfavorably in a cost: benefit analysis to two commercially available polymers for the removal of residual CaCO3. Neutralisation of AMD in control samples resulted in decreased concentrations of the target metal group (Ni, Zn, Cu, Cd, and Pb) by hydroxide precipitation, co-precipitation, and adsorption. Equilibrium speciation modeling showed that the HS-metal binding affinity controlled the effectiveness of HS addition for metal removal. The low HS complexation affinity of Ni and Zn resulted in no additional metal removal by HS dosing. The removal of Cu was enhanced by over 50% for SEHA 20 during-neutralisation conditions neutralised by both NaOH and Ca(OH)2. Up to 80% lower Cd concentrations were observed for all HS dose conditions when neutralised by Ca(OH)2. Data for CaCO3 HS dosed metal removal was statistically indeterminate. The high detection limit for Pb made any HS dosed removal enhancement difficult to identify, which was unfortunate as Pb has a high HS complexation affinity (Čežı́ková, Kozler et al. 2001; Milne, Kinniburgh et al. 2003). A simple cost: benefit analysis showed that the additional removal of metals by HS dosing was less efficient than conventional neutralisation alone, on a cost basis. Overall, incorporation of HS into AMD treatment results in improved water quality for CaCO3 neutralisation and lower concentrations of metals with a high HS binding affinity, for some conditions. However, further investigation is required to improve the feasibility of HS incorporation into the AMD neutralisation process.

Phosphonate antiscalants are commonly used in nanofiltration and reverse osmosis water treatment to prevent membrane fouling by mineral scale. In many circumstances it is desirable to remove these phosphonate compounds before concentrate disposal or further treatment. This research investigated the removal of phosphonate compounds from simulated membrane concentrate solutions using ferric hydroxide adsorbents. Two phosphonate antiscalants were investigated, Permatreat 191® (PT191) and nitrilotrimethylphosphonic acid (NTMP). Batch adsorption isotherms and column breakthrough and regeneration experiments were performed on two commercial adsorbents and a ferric hydroxide loaded polyacrylonitrile fiber adsorbent prepared in our laboratory. The best performing adsorbent was Granular Ferric Hydroxide® (GFH) obtained from GEH Wasserchemie. Adsorption isotherms measured after 24-hour equilibration periods showed initial concentration effects, whereby the isotherms were dependent on the initial adsorbate concentration in solution. Significant differences in adsorption behavior were observed between the PT191 and the NTMP adsorbates. Differences in adsorption behavior between NTMP and PT191 are all consistent with the PT191 containing fewer phosphonate functional groups per molecule than NTMP. Desorption rates were bimodal, with 40-50% of the adsorbed phosphonate being released on a time scale of 10-24 hours, while the remaining fraction was released approximately one order of magnitude more slowly. The slow desorbing fraction primarily resulted from equilibrium effects resulting from significant phosphonate adsorption, even in 1.0 mol/L NaOH solutions. Complete regeneration could not be achieved, even after eluting the adsorbent columns with more than 300 bed volumes of 1.0 mol/L NaOH. However, the incomplete regeneration had only a minor effect on phosphonate uptake in subsequent column breakthrough experiments.

A novel cryptand was synthesized which contained a 3,5-disubstituted-4- oxahexacyclo[5.4.1.02,6.03,10.05,9.08,11] dodecane "cage" moiety. In alkali metal picrate extraction experiments the cryptand exhibited high avidity towards Rb+ and Cs+, when compared with the corresponding model compound. A computational study of a series of cage-functionalized cryptands and their alkali metal-complexes was performed. The X-ray crystal structure of a K+-complexed bis-cage-annulated 20-crown-6 was obtained. The associated picrate anion was found to be intimately involved in stabilization of the host-guest complex. The interaction energy between the host-guest complex and picrate anion has been calculated, and the energy thereby obtained has been corrected for basis set superposition error.

This master thesis deals with synthesis of 6I -N-monosubstituted β-CD bearing a linear spacer of various lenghts containing disulfidic bond and terminated by amine. Whole series was succesfully prepared by nucleophilic substitution of toluenesulfonyl group on tosyl β-CD by a spacer's amine group. In case of the shortest spacer (cystamine) 35 % yield was achieved. Synthesis of β-CD derivatives using longer and more lipophilic spacer derived from di-, tri- and tetraethylenglycol yielded 66 to 85 %. The oligoethylene spacers were prepared by standard chemical modifications. A separation method using n-butanol elution mixtures was optimized for isolation of β-CD derivatives. To better understand the β-CD derivative behavior in solution, molecular dynamics (MD) computations were used. The synthetized species were intended to be used for fluorescent sensor construction. For the same reason the inclusion of small organic molecules in β-CD cavity was studied with molecular dynamic simulations. MD method for computation of relative binding energy was optimized and gave values of right sign and order of magnitude.

Des solutions d'acides carboxyliques contenant principalement de l'acide formique sont obtenues par oxydation photo-Fenton des polysaccharides. Une irradiation dans le visible de 60 W sous des conditions douces suffit à fournir des résultats reproductibles. Les produits d'oxydation issus d'amidon de pomme de terre et d'amidon de blé ont montré des capacités de complexation comparables aux solutions commerciales d'acide gluconique et glucuronique.Un système d'oxydation innovant, comprenant des sels d'halogénures et du DMSO, convertit quantitativement le HMF en DFF. Cette méthode permet aussi la transformation one-pot du fructose en DFF avec de bons rendements. Selon l'étude mécanistique, le bromo-HMF serait un intermédiaire réactionnel. / Solutions of carboxylic acids, containing mainly formic acid, are produced under photo-Fenton conditions. Visible irradiation with a 60 W spot is sufficient to provide reproducible results under mild conditions. The oxidation products of potato starch and wheat starch have shown Ca sequestering properties similar to those of gluconic and glucuronic acids.Using halide salts and DMSO, an innovating method has been elaborated for the selective oxidation of HMF to DFF with quantitative yields. The one-pot transformation of fructose to DFF occurs with fair yields. Based on the mechanistic study, Br-HMF would be the reaction intermediate.

Arthrospira platensis ou Spirulina é uma microalga com alto valor nutricional. Foram preparados extratos de Spirulina, caracterizados e aplicados como estabilizadores de emulsão de óleo de girassol comercial em água (O/A) (10% v/v) na ausência e na presença de quatro tipos de hidroxipropil metilcelulose (HPMC). Os extratos brutos de Spirulina foram preparados em tampões a pH 6 (EB6) e pH 8 (EB8) por sonicação para promover a lise celular e a libertação de proteínas e fosfolípides; Parte dos extratos foi centrifugada (EC6 ou EC8). Independentemente das condições de extração, todos os extratos apresentados apresentaram valores de potencial-&#950 médio variando de - (16 ± 2) mV a - (20 ± 2) mV, tamanho médio variando de (108 ± 52) nm a (306 ± 68) nm e atividade interfacial. As emulsões O/A preparadas com extratos de Spirulina (10 g / L) exibiram partículas com potencial- médio variando de - (16 ± 2) mV a - (27 ± 4) mV, tamanho médio variando de ~ 70 nm (EB6 ou EB8) a ~ 700 nm (EC6 ou EC8). No entanto, o EB6 levou a emulsões ligeiramente mais estáveis do que as outras. A combinação de EB6 (10 g / L) e HPMC (1,0 % m/m) levou a um aumento substancial na estabilidade da emulsão, embora os valores de potencial- diminuíram uma ordem de grandeza. Em particular, a HPMC com a maior massa molar e o maior grau de substituição de grupos metila conduziu a i) camada interfacial mais robusta resultante da formação de complexos entre cadeias HPMC e proteínas EB6 e (ii) meio contínuo mais viscoso. / Arthrospira platensis or Spirulina is a microalga with a high nutritional value. Extracts of Spirulina were prepared, characterized and applied as oil in water (O/W) (10 % v/v) emulsion stabilizers in the absence and presence of four types of hydroxypropyl methylcellulose (HPMC). The emulsions were prepared with edible sunflower oil. Crude extracts of Spirulina were prepared in buffers at pH 6 (CE6-Crude extract pH6) and pH 8 (CE8-Crude extract pH8) by sonication to promote cell lysis and protein and phospholipids release; part of the extracts was centrifuged (CCE6 or CCE8). Regardless of the extraction conditions, all extracts presented mean -potential ranging from (16 ± 2) mV to (20 ± 2) mV, mean diameter ranging from (108 ± 52) nm to (306 ± 68) nm and interfacial activity. The emulsions prepared with Spirulina extracts (10 g/L) displayed particles with mean -potential ranging from (16 ± 2) mV to (27 ± 4) mV, mean diameter ranging from ~ 70 nm (CCE6 or CCE8) to ~ 700 nm (CE6 or CE8). However, CE6 led to emulsions slightly more stable than the others did. The combination of CE6 (10 g/L) HPMC (1.0 wt %) led to substantial increase in the emulsion stability, although the -potential values decreased one order of magnitude. Particularly, the HPMC with the highest molecular weight and highest methyl substitution degree led to the most (i) robust interfacial layer resulting from the complex formation between HPMC chains and CE6 proteins and (ii) viscous continuous medium.

Dentre as espécies químicas metálicas responsáveis pela contaminação do meio aquático, mercúrio e outros compostos mercuriais têm recebido atenção especial devido a sua alta toxicidade. Os ligantes de ocorrência natural formam complexos com íons de Hg2+, influenciando a sua biodisponibilidade. Em meio a esses ligantes, dá-se destaque aos ligantes heterogêneos de ocorrência natural (LHON), tais como substâncias húmicas e argilominerais, por sua elevada capacidade de adsorção/complexação com íons metálicos. Entre as técnicas existentes para a determinação de Hg(II), as voltamétricas, em especial a voltametria de redissolução anódica, ganham destaque devido as características que as tornam mais adequadas para estudos envolvendo interações entre LHON e Hg(II), tais como alta sensibilidade e mínima manipulação da amostra. Uma estratégia para se evitar os problemas causados pela passivação do eletrodo de trabalho por adsorção de matéria orgânica, bem como para se aumentar a robustez da técnica, é a mecanização da análise em sistema de análise por injeção sequencial (SIA). Baseando-se neste contexto, este trabalho teve por objetivo o desenvolvimento de um sistema SIA com detecção voltamétrica, especificamente voltametria de onda quadrada (SIA-SWV), para se determinar Hg(II) em estudos de adsorção com ácido húmico, permitindo o procedimento de troca de meio em linha, sem contato do eletrodo com a atmosfera, contornando problemas de reoxidação do Hg pelo O2 atmosférico e a distorção de sinal causada pela saturação dos sítios de adsorção presentes na camada de difusão na etapa de redissolução, tornando as medidas voltamétricas mais reprodutíveis e rápidas. O sistema SIA-SWV desenvolvido tem potencialidade para a realização de medidas da fração de Hg(II) lábil e livre em águas naturais, mostrando-se também adequado para a elaboração de estudos de adsorção envolvendo a presença de ligantes orgânicos devido a ausência de passivação do eletrodo de trabalho e a possibilidade do uso do procedimento de troca de meio. O limite de detecção (0,02 &#181;mol L-1) atende aos limites permitidos pelo CONAMA (0,05 &#181;mol L-1) para o lançamento de efluentes. Isso mostra a potencialidade do sistema SIA-SWV para a realização de determinações de Hg2+ e como um recurso para auxiliar no controle da concentração da espécie em efluentes antes do lançamento em corpos dágua. Dentre os LHONs empregados, o ácido húmico foi o que apresentou maior capacidade de adsorção por Hg(II) (Kf = 295/304 ± 1 &#181;mol1-1/n g-1 L1/n e Qmax = 537 ± 30 &#181;mol g-1. Essas evidências indicam que em corpos de água com presença de MOD, as substâncias húmicas, em especial os grupos carboxílicos nelas presentes, são uns dos principais reguladores da disponibilidade e mobilidade de Hg(II). É demonstrado que a presença de partículas de argilominerais também influencia na capacidade de adsorção (sob as condições de pH 6,0 e força iônica) pelas substâncias húmicas na adsorção por Hg(II). O processo de dessorção de Hg(II) em HCl 0,06 mol L-1 foi mais favorecido para a condição em sistema ternário, com porcentagens de dessorção variando entre 74 e 100% . Foi evidenciado que a diminuição do pH influencia no processo de adsorção/complexação devido a competição entre este processo e a protonação dos sítios de adsorção presentes no ácido húmico. Já com o aumento da força iônica ocorre o aumento da adsorção/complexação por Hg(II), o que sugere a formação de ligações covalentes é que governa o processo de interação entre Hg(II) e ácido húmico. / Among the chemical species responsible for metal contamination of the aquatic environment, mercury and other mercury compounds have received special attention due to its high toxicity. The naturally occurring ligands form complexes with Hg2+ ions, influencing their bioavailability. Through these ligands, there is emphasis on heterogeneous naturally occurring ligands (HNOL), such as humic substances and clay minerals because of its high adsorption capacity/complexation with metal ions. Between the techniques for the determination of Hg(II), anodic stripping voltammetry stands out because of characteristics that make it more suitable for studies involving interactions between HNOL and Hg(II), such as high sensitivity and minimal sample handling. A strategy to avoid problems caused by the passivation of the electrode surface by adsorption of organic matter and to increase robustness of the technique is the mechanization of the analysis system by sequential injection analysis (SIA). The present study aimed at developing a SIA system with voltammetric detection, specifically square wave voltammetry (SIA-SWV), to determine Hg(II) in adsorption studies with humic acid, automating the medium exchange procedures avoiding the contact of the electrode with the atmosphere, overcoming problems of Hg0 reoxidation by atmospheric O2 and signal distortion caused by saturation of adsorption sites present in the diffusion layer in the stripping step, making voltammetric measurements more reproducible and rapid. The proposed SIA-SWV system has the potential to carry out measurements of the labile and free fraction of Hg2+ in natural waters, being also suitable for the development of adsorption studies involving the presence of organic ligands. The limit of detection (0.02 &#181;mol L-1) attends the limits allowed by CONAMA (0.05 &#181;mol L-1) for the discharge of effluents. This shows the potential of the SIA-SWV system to perform determinations of Hg2+ and as an auxiliary technique for monitoring the concentration of the species in wastewater before release into water bodies. Among the studied LHONs, the humic acid showed the highest adsorption capacity for Hg (II) (Kf = 295/304 ± 1 &#181;mol1-1/n g-1 L1/n and Qmax = 537 ± 30 &#181;g mol-1). The results suggest that in waters rich in dissolved organic matter (DOM) carboxylic groups in humic acids are among the major regulators of the availability and mobility of Hg(II). It is also shows that clay particles influences the adsorption capacity (under conditions of pH 6.0 and ionic strength) of the humic substances in the adsorption of Hg(II). The process of desorption of Hg (II) in HCl 0.06 mol L-1 was most favored for the condition in the ternary system, with desorption percentages ranging from 74 to 100%. It was evidenced that the decrease of the pH influences the adsorption/complexation because of the competition between this process and protonation of the adsorption sites present in the humic acid. The increase in ionic strength increases adsorption/complexation by Hg (II), suggesting the formation of covalent bonds is governing this process of interaction between Hg(II) and humic acid.

Deux thématiques principales ont été étudiées au cours de cette thèse. La première partie porte sur la synthèse de complexes de manganèse dérivés de porphyrines et de salens. L'activité catalytique de ces complexes a été évaluée dans l'époxydation d'alcènes non-Fonctionnalisés. Suite à cette étude, les propriétés électroniques des ligands ont été étudiées, notamment par le biais de la complexation d'anions. Dans une deuxième étape, nous nous sommes intéressés à la synthèse de phosphines P-Chirogéniques. Afin de trouver un substitut à l'éphédrine, couramment utilisée dans ces synthèses, des dérivés du (1S,2S)-2-Aminocyclohexanol et de la D-Glucosamine ont été synthétisés. L'utilisation de groupements sulfonamides a permis l'obtention aisée d'oxazaphospholidines N-Tosylées. L'un ou l'autre diastéréoisomère de cet hétérocycle peut être obtenu en fonction du degré d'oxydation du réactif phosphoré utilisé. Avec cette stratégie, divers oxydes de phosphines ont été obtenus avec de bons rendements et de bonnes énantiosélectivités / This thesis is divided in two parts. The first part focuses on the synthesis of manganese complexes derived from porphyrins and salens. The catalytic activity of these complexes were evaluated toward the epoxidation of unfunctionalized alkenes. Next, the electronic properties of the ligands were evaluated using their anion binding properties. In a second part, we were interested in the synthesis of P-Chirogenic phosphines. In order to find a surrogate to ephedrine, that is commonly used in those syntheses, derivatives from (1S,2S)-2-Aminocyclohexanol and D-Glucosamine were synthesized. The use of sulfonamides allows the access to N-Tosylated oxazaphospholidines. Both diastereoisomers could be synthesized depending on the oxydation state of the phosphine precursor. Using this strategy, various phosphine oxides were obtained in good yields and enantioselectivities