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Harron, Eilis Antonia. "Imido and amido compounds of Sn(II) and Mn(II)." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619780.
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Maciel, Jhonny Willians de Oliveira. "Complexos de Fe(II), Mn(II), Cu(II) e Zn(II) derivados de um ligante do tipo oxamato funcionalizado: síntese e caracterização." Universidade Federal de Goiás, 2018. http://repositorio.bc.ufg.br/tede/handle/tede/9038.
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New supramolecular systems based on metal complexes of formula [Fe(H2pcpa)2(H2O)2] (3), [Mn(Hpcpa)(H2O)3]n•1/2H2O (4), [Zn(Hpcpa)(H2O)3]n•1/2H2O (5) and [Cu2(Hpcpa)2(bipy)2]•5,6H2O (6) [H2pcpa- and Hpcpa2- ion derivative of EtH2pcpa (1) = N-(4-carboxyphenyl)oxamic ethyl ester] have been synthesized and describe in this work. The structure of 3 consists of discrete Fe(II) units, each metal ion is six-coordinate in a distorted octahedral environment with four oxamate-oxygens from a H2pcpa- ligand in the basal plane and two water molecules in the apical position. 4 and 5 is a neutral zigzag chain of Mn(II) and Zn(II) ions, respectively, bridged by Hpcpa2- ligands exhibiting the bidentate/monodentate coordination mode. Each metal ion is building a somewhat distorted octahedral surrounding. The distance between metals ions intrachain is 11.456 Å (4) and 11.325 Å (5). Complex 6 consists of a dimer in which the Cu(II) ions is found in a square-shaped pyramidal geometry connected by two Hpcpa2- and the 2,2'-bipyridine as a terminal ligand.
Foram obtidos novos sistemas supramoleculares baseados em compostos de coordenação com o ligante ácido N-(4-carboxifenil) oxâmico etil éster (EtH2pcpa/1) e os metais Fe(II), Mn(II), Cu(II) e Zn(II). As sínteses, caracterizações espectroscópicas e elucidação das estruturas cristalinas de quatro compostos inéditos de fórmula [Fe(H2pcpa)2(H2O)2] (3), [Mn(Hpcpa)(H2O)3]n•1/2H2O (4), [Zn(Hpcpa)(H2O)3]n•1/2H2O (5) e [Cu2(Hpcpa)2(bipy)2]•5,6H2O (6) foram descritas nesse trabalho. O complexo 3 formou monocristais de cor laranja amarronzada, cuja a estrutura consiste em um monômero de Fe(II). Cada íon de Fe(II) é hexacoordenado com esfera de coordenação composta de duas moléculas de água posicionadas em trans e quatro oxigênios-oxamato de dois ligante H2pcpa-. Os compostos 4 e 5 formaram monocristais transparentes incolores cujas estruturas cristalinas são formadas por cadeias em ziguezague neutras de íons Mn(II) e Zn(II), respectivamente. Cada íon metálico está hexacoordenado com as três moléculas de água posicionadas em Meridional, dois oxigênios-oxamato de um ligante Hpcpa2- e um oxigênio-carboxilato de um outro grupo do Hpcpa2-. A distância entre os metais intracadeia Mn...Mn no complexo 4 é de 11,456 Å e Zn...Zn no complexo 5 é de 11,325 Å. O complexo 6 formou monocristais azuis, a estrutura consiste em um dímero em que o íon de Cu(II) encontra-se penta coordenado em uma geometria piramidal de base quadrada com dois íons de Cu(II) ligados por dois ligantes Hpcpa2- e com o ligante 2,2'-bipiridina atuando como ligante terminal.
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Mantel, Claire. "Etude des propriétés électroniques par RPE à haut champ et à haute fréquence de complexes mononucléaires de Mn(II) et Mn(III) et binucléaires de Mn(II)." Université Joseph Fourier (Grenoble), 2004. http://www.theses.fr/2004GRE10148.
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Ce mémoire est consacré à l'étude RPE à haut champ et haute fréquence de complexes mononucléaires de Mn(II) et Mn(III) ainsi que de complexes binucléaires de Mn(II). Une nouvelle série de complexes mononucléaires de Mn(III) hexacoordines du type [MnL(X)3](L=Ligand tridentate azote et X=anion) a été synthétisée. Les distorsions tétragonales de ces complexes ont été reliées au signe de D : D est positif pour une compression et négatif pour une élongation. Une série de complexe mononucléaires de Mn(II) pentacoordinés du type [MnL(X)2] a aussi été synthétisée. Lorsque le Mn(II) est coordiné à des ligands à champ faible, ceux-ci gouvernent D. En revanche, pour des complexes ne possédant que des ligands à champ fort, D est contrôlé par le nombre de cooordination du Mn. Enfin, une nouvelle méthode d'analyse basée sur une étude RPE multifréquence a été appliquée à deux complexes binucléaires de Mn(II) pour lesquels les deux ions métalliques sont couplés antiferromagnétiquementThis manuscript describes a high field and high frequency EPR study of mononuclear Mn(II) and Mn(III) as well as binuclear Mn(II) complexes. A new series of six-coordinated mononuclear Mn(III) complexes of general formula [MnL(X)3] (L=nitorgen tridentate ligand and X=anion) has been synthesized. Tetragonal distorsions of these complexes have been correlated with the sign of D : D is positive for a compression and negative for an elongation. A series of five-coordinated mononuclear Mn(II) complexes of general formula [MnL(X)2] was also synthesized. When Mn(II) is coordinated with weak field ligands, they control D. In contrast, for complexes with only strong fields ligands, D is governed by the coordination number of Mn. Finally, a new method of analysis based on a multifrequency EPR study was applied to two binucleat Mn(II) complexes in which the two metallic ions are antiferromagnetically coupled
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Robinson-Miller, Adam. "A study of Mn(II)/Mn(III) oxidation catalysts in alkene epoxidation and chromophore bleaching." Thesis, Northumbria University, 2015. http://nrl.northumbria.ac.uk/23589/.
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My original contribution to knowledge is presented in this work, in the new application of a previously synthesised manganese (III) complex as an effective and selective oxidation catalyst. Development of a series of conditions in which epoxidation reactions can successfully be undertaken was established with both hydrogen peroxide and n-tetrabutyl ammonium oxone. Epoxidations undertaken with hydrogen peroxide were commensurate with a competitive catalase like reaction. Establishment of the factors that drive the catalase type of oxidative reaction with the Mn(DMHP)2.Cl complex, including Michaelis Menten kinetic parameters and the effects of temperature and pH, allowed for a protocol to be set up that can favour epoxidation over catalase-like dismutation of hydrogen peroxide. To coincide with epoxidation work on hydrogen peroxide, a DFT study on the proposed reaction intermediates is presented with a focus on the likely active catalytic species. The role of imidazole was probed and showed that coordination of imidazole is slightly unfavoured and will be in equilibrium in solution, which coincided with experimental observations that imidazole was required in a slight excess for successful epoxidation. This work further demonstrated that in acidic conditions an oxomanganese(V) species is highly favoured and corresponds excellently to what is observed experimentally where very good conversion to epoxide of cyclooctene is achieved at pH 4.7. Work utilising n-tetrabutyl ammonium oxone as oxidant exhibited good to excellent conversions, and a trend was observed of high selectivity to strained cyclic alkenes. This was further probed by a joint study using a series of strained substrates that were synthesised and computational chemistry to determine the strains over the alkene bond. Collaborative work with the national mass spectrometry service allowed for identification of the intermediates of the reaction my mass spectrometry coupled with a UV/Vis spectroscopy study. Identification of an oxomanganese(V) species is presented in mass spectrometry as the active intermediate in epoxidations using n-tetrabutyl ammonium oxone . A study as to the effects of additive bases using cyclic voltammetry demonstrated a significant electronic effect on the oxidation potential of the catalyst as the source of the inductive effect, identification by mass spectrometry and UV/Vis showed direct evidence of axial ligation of the additive bases. Using an industrial manganese (II) catalyst in the bleaching of red stains (β-carotene and crocin), a protocol for bleaching was established, using UV/Vis as a method of analysis. Synthesis of a series of chelants which are used to stabilise the catalyst in the formulation was undertaken. Testing of the chelants in the bleaching system demonstrated their utility in the wash system across a pH range. The utility of surfactant when using chelants with the catalyst was established to give excellent bleaching and stability of the catalyst.
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Giovedi, Claudia. "Comportamento eletroquímico dos metais Co(II), Ni(II), Mn(II), Fe(II) e Zn(II) na presença do ligante azoteto." Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-02122009-152133/.
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O comportamento eletroquímico dos metais cobalto(II), níquel(II), manganês(II), ferro(II) e zinco(II) na presença do ligante azoteto foi estudado em duas condições: variando-se a concentração do ligante em solução de 0 a 2,0 mol/L e apenas tendo-o pré-adsorvido na superficie do eletrodo de mercúrio, buscando-se assim esclarecer os fenômenos determinantes na extensão da atuação do ligante como mediador facilitando a etapa de transferência de elétrons do eletrodo para o metal. Os resultados obtidos nas duas séries de experimentos mostraram ser a extensão da atuação do ligante como mediador dependente do metal estudado. No primeiro caso a adição gradativa de azoteto às soluções que contêm os cátions metálicos causa a antecipação progressiva da onda de redução dos metais Co(II) e Ni(II), o deslocamento para potenciais progressivamente mais negativos no caso dos metais Mn(II) e Fe(II) e, para o Zn(II), uma pequena antecipação em baixas concentrações do ligante e em seguida o aumento de sobretensão. Tendo-se apenas o ligante adsorvido na superficie do eletrodo, verifica-se a diminuição da sobretensão de redução dos metais Co(II) e Ni(II), um pequeno aumento no caso do metal Zn(II) e a completa eliminação da reação de eletrodo para o Mn(II). As diferenças observadas nos dois experimentos, comprovaram a importância do fenômeno de complexação na superficie do eletrodo para que se verifique a atuação do ligante como mediador. No entanto, apesar da necessidade de ocorrer a interação do metal com o ligante para facilitar a reação de transferência de elétrons, o complexo formado na superficie do eletrodo não pode ser termodinamicamente mais estável que o aquo-íon do metal, pois neste caso ao invés da diminuição da sobretensão de redução do metal irá se registrar o deslocamento do potencial de redução diretamente para potenciais mais negativos.The electrochemical behaviour of cobalt(II), nickel(II), manganese(II), iron(II) and zinc(II) was studied in the presence of azide in two conditions: varying the ligand concentrations in solution from 0.0 to 2.0 mol/L and just pre-adsorbing it onto the mercury electrode surface, in order to evaluate the determining aspects on the extent of the action of the ligand as a mediator in facilitating electron transfer. The results obtained in the two sets of experiments showed to what extent the action of the ligand as a mediator is dependent on the metal studied. In the first case, the addition of azide to solutions of these metaIs causes the following: a progressive anticipation in the reduction waves of Co(lI) and Ni(II); the shift towards more negative potentials for Mn(II) and Fe(II); and for Zn(TT) a small shift towards more positive potentials at low azide concentrations followed by a shift towards more negative potentials. The experiments carried out with the pre-adsorption ofthe azide onto the mercury surface showed the shift of the reduction waves of Co(lI) and Ni(II) towards more positive potentials, a small shift towards more negative potentials for Zn(II) and the complete elimination of the electrode reaction for Mn(II). The differences observed in the two experiments proved the importance of the complexation phenomenon onto the electrode surface in order to occur the action of the ligand as a mediator. However, inspite of the need of the interaction between metal and ligand to facilitate the electron transfer, the complex formed onto the electrode surface cannot be thermodynamically more stable than its metal aquo-ion, as in this case it will be observed the shift of the reduction potential towards more negative potentials.
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Murray, Karen J. "Acceleration of Cr(III) and Co(II) oxidation by Mn(II)-oxidizing bacteria /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3191987.
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PIMENTEL, AMANDA MAURO RODRIGUES. "REMOVAL OF CO(II) AND MN(II) FROM AQUEOUS SOLUTIONS USING R. OPACUS BIOMASS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2011. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=19096@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOA busca por tecnologias alternativas e de baixo custo operacional para a remoção de metais em efluentes tem direcionado a atenção para a biossorção. Recentemente vários materiais de origem biológica, como bactérias e resíduos agro-industriais têm sido utilizados para a remoção de íons metálicos de efluentes industriais. A biossorção de metais pesados por espécies biológicas envolve vários mecanismos que, em geral, dependem das espécies biológicas utilizadas e do processamento da biomassa. O cobalto e o manganês são amplamente utilizados em muitas aplicações industriais, e consequentemente, estão presentes nos efluentes provenientes de vários processos industriais, como por exemplo na mineração e produção de ligas. O objetivo deste trabalho foi investigar a eficiência do Rhodococcus opacus, que apresenta vários grupamentos fenólicos e carboxílicos (capazes de interagir com íons metálicos em solução), como adsorvente para a remoção de Co(II) e Mn(II) de soluções aquosas, visando futuras aplicações para o tratamento de efluentes. A caracterização física da superfície do R. opacus foi realizada com MEV, potencial zeta e análises de FTIR. A biomassa, R. opacus, foi previamente tratada com 0,1 mol.L(-1) NaOH e usada em todos os experimentos de biossorção. Todos os testes de biossorção foram realizados em batelada e os parâmetros avaliados foram: pH, concentração da biomassa e do metal, tempo de contato e temperatura. Os melhores valores de pH para a biossorção de Co(II) e Mn(II) foram 7,0 e 5,0, respectivamente. Para ambos os metais estudados, a capacidade de biossorção específica foi maior em soluções contendo baixas concentrações de metais. Para os dois metais, o processo de biossorção foi melhor descrito pelo modelo de Langmuir e pelo modelo cinético de pseudo segunda ordem. Os parâmetros termodinâmicos como DeltaG, DeltaS e DeltaH foram calculados e os processos de biossorção para a remoção do Co(II) e do Mn(II) a partir de soluções aquosas foram consideradas reações endotérmicas e exotérmicas, respectivamente. Este trabalho mostra que o R. opacus pode ser aplicado para a remoção de íons de Co(II) e Mn(II) de soluções aquosas. Após 180 minutos de contato da biomassa com as soluções contendo Co(II) e Mn(II), 84 por cento e 97 por cento dos íons metálicos presentes em solução foram removidos.
The search for alternative technologies and low operating cost for removal of heavy metals from effluent has directing attention to biosorption. Recently, various biological materials, such as bacteria and agro‐waste, have been used for removal of metallic ions from industrial effluents. Biosorption of heavy metals by biological species involves several mechanisms that, in general, depending on the type of specie used and biomass processing procedure. Cobalt and manganese are widely used in many industrial applications, consequently they are present in effluent derived from various industrial processes, for example: mining, alloy production. The objective of this work is to investigate the efficiency of Rhodococcus opacus, which presents various phenolic and carboxylic groups (able to interact with metal ions in solution), as an adsorbent for the removal of Co(II) and Mn(II) from aqueous solutions, aiming future applications for the treatment of effluents. Surface physical characterization of R. opacus was carried by MEV, zeta potential and FTIR analysis. The biomass, R. opacus, was previously treated with 0.1 mol.L(-1) NaOH solution and used in all biosorption experiments. All the biosorption tests were carried out in batch and the parameters evaluated were: pH, concentration of biomass and metal, contact time and temperature. The best pH value for biosorption of Co(II) and Mn(II) were 7.0 and 5.0 respectively. For both metal studied, the specific biosorption capacity was higher in solutions containing low metals concentrations. For both metals, the biosorption process was better described by the Langmuir and pseudo-second-order kinetic models. The thermodynamics parameters, such as DeltaG, DeltaS and DeltaH were calculated and the biosorption process for Co(II) and Mn(II) removal from the aqueous solutions were considered endothermic and exothermic reactions, respectively. This work shown the R. opacus can be applied for removal Co(II) and Mn(II) ions from aqueous solutions. After 180 min contact of biomass with solutions containing Co(II) and Mn(II), 84 per cent and 97 per cent of the metallic ion present in the solutions were removed.
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Vallejo, Adriana Cossu. "Síntese, caracterização e estudo do comportamento térmico dos 3-metoxibenzoatos de Mn(II), Co(II), Ni(II), Cu(II) e Zn(II), no estado sólido /." Araraquara [s.n.], 2004. http://hdl.handle.net/11449/97870.
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Orientador: Massao IonashiroBanca: Salvador Claro Neto
Banca: Mercedes de Moraes
Resumo: Os 3-metoxibenzoatos de Mn (II), Co (II), Ni (II), Cu (II) e de Zn (II), foram preparados fazendo-se reagir os respectivos carbonatos básicos com ácido 3-metoxibenzoico, ambos em suspensão aquosa à temperatura de ebulição. Os compostos assim obtidos foram estudados através da complexometria com EDTA, Termogravimetria (TG) e difratometria de raios X pelo método do pó. As curvas TG foram obtidas em atm de ar sintético e em cadinho de Pt para a amostra e referencia. Os resultados obtidos por termogravimetria (TG), complexometria com EDTA, possibilitaram estabelecer a estequiometria e o grau de hidratação dos compostos, que apresentaram fórmula geral: M(3-MeO-BZ) 2 nH2O com n= 0,5; 1,0;1,5 e 2,0. As curvas TG também permitiram verificar a estabilidade térmica, bem como o processo de decomposição térmica, destes compostos. Os difratogramas de raios X, pelo método do pó, mostraram que todos os compostos possuem estrutura cristalina, com exceção do composto níquel, obtidos no estado não cristalino.
Abstract: The 3-methoxybenzoates of Mn (II), Co (II), Ni (II), Cu (II) and Zn (II) were prepared by reacting the respective basic carbonates with methoxybenzoates acid, both in aqueous suspension in a heating temperature. The compounds therefore obtained were studied by complexometric (EDTA), thermogravimetry, derivative thermogravimetry and differential thermal analysis (TG. DTG, DTA) and X-Ray diffractometry. The curves (TG) were obtained in atmosphere synthetic air and in Platinum crucible as samples and references. The results obtained by thermogravimetry (TG) and complexometric (EDTA) enabled to establish the stoichiometry and the hydration degree of these compounds which presented the general formula: M(3-MeO-BZ)2 nH2O with n=0,5; 1,0; 1,5 and 2,0. Also the curves (TG) permitted to verify as the thermal stability as the decomposition process of these compounds. The X-Ray powder patterns made possible to show that all the compounds had crystalline structure, except the Nickel (II) compound, shapeless by itself.
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Carvalho, Cláudio Teodoro de. "Síntese, caracterização e estudo do comportamento térmico dos 2-metoxibenzoatos de Mn(II), Co(II), Ni(II), Cu(II) e Zn(II) no estado sólido /." Araraquara : [s.n.], 2006. http://hdl.handle.net/11449/97865.
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Orientador: Massao IonashiroBanca: João Olimpio Tognolli
Banca: Salvador Claro Neto
Resumo: Carbonatos de Mn(II), Co(II), Ni(II), Cu(II) e Zn(II) foram preparados por adição lenta da solução saturada de hidrogeno carbonato de sódio com gotejamento contínuo às soluções dos respectivos cloretos metálicos, exceto para o cobre, até a total precipitação do íon metálico. Os precipitados foram lavados com água destilada para eliminar os íons cloretos e teste qualitativo com solução de AgNO3/HNO3 foi realizado para confirmar a ausência destes, e após isso, foi mantida em suspensão. Os compostos no estado sólido foram preparados pela mistura dos respectivos carbonatos metálicos com o ácido 2-metoxibenzóico (2-MeO-HBz). A suspensão aquosa foi aquecida lentamente próximo da ebulição até neutralização total dos carbonatos. As soluções resultantes depois de arrefecidas foram mantidas em banho de gelo para recristalizar o ácido em excesso e filtradas. Assim, as soluções aquosas dos metoxibenzoatos metálicos foram concentradas em banho maria e o precipitado seco resultante deste processo colocado em um dessecador contendo cloreto de cálcio. O composto de cobre devido a sua baixa solubilidade foi preparado pela adição lenta com gotejamento contínuo de solução do 2-metoxibenzoato de sódio 0.1 mol L-1 à solução de sulfato de cobre, até a total precipitação do íon cobre e o precipitado lavado com água destilada para eliminação do íon sulfato e teste qualitativo de confirmação realizado com BaCl2 0.1 mol L-1, em seguida filtrada em papel de filtro Whatman 40 e o precipitado após seco foi colocado em dessecador contendo cloreto de cálcio. Os compostos sintetizados foram investigados por meio de espectroscopia de infravermelho, difratometria de raio X pelo método do pó, termogravimetria e análise térmica diferencial simultânea (TG-DTA), termogravimetria, termogravimetria derivada (TG/DTG), calorimetria exploratória diferencial (DSC) e outros métodos de análise.
Abstract: Carbonates of Mn (II), Co (II), Ni (II), Cu (II) and Zn (II) were prepared by adding slowly with continuous stirring saturated sodium hydrogen carbonate solution to the corresponding metal chloride solutions (except copper), until total precipitation of the metal ions. The precipitates were washed with distilled water until elimination of chloride ions (qualitative test with AgNO3/HNO3 solution) and maintained in aqueous suspension. olid state Mn (II), Co (II), Ni (II) and Zn (II) compounds were prepared by mixing the respective metal carbonates with 2-methoxybenzoic acid 99% (2-MeO-HBz) obtained from Aldrich, in slight excess. The aqueous suspension was heated slowly up to near ebullition, until total neutralization of the respective carbonates. The resulting solutions after cooled were maintained in an ice bath to recrystallize the acid in excess and filtered through a Whatman nº 40 filter paper. Thus, the aqueous solutions of the respective metal 2-methoxybenzoates were evaporated in a water bath until near dryness and kept in a desiccator over calcium chloride. The copper compound due to its low solubility was prepared by adding slowly, with continuous stirring, the aqueous solution of Na-2-MeO-Bz 0.1 mol L-1 to the respective metal sulphate solution, until total precipitation of the metal ions. The precipitate was washed with distilled water until elimination of the sulphate ion, filtered through and dried on Whatman no42 filter paper, and kept in a desiccator over anhydrous calcium chloride, under reduced pressure to constant mass. The compounds were investigated by means of infrared spectroscopy, X-Ray powder diffractometry, simultaneous thermogravimetry and differential thermal analysis (TG-DTA), Thermogravimetry derivative termogravimetry (TG/DTG), differential scanning calorimetry (DSC) and other methods of analysis.
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Carvalho, Cláudio Teodoro de [UNESP]. "Síntese, caracterização e estudo do comportamento térmico dos 2-metoxibenzoatos de Mn(II), Co(II), Ni(II), Cu(II) e Zn(II) no estado sólido." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/97865.
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Carbonatos de Mn(II), Co(II), Ni(II), Cu(II) e Zn(II) foram preparados por adição lenta da solução saturada de hidrogeno carbonato de sódio com gotejamento contínuo às soluções dos respectivos cloretos metálicos, exceto para o cobre, até a total precipitação do íon metálico. Os precipitados foram lavados com água destilada para eliminar os íons cloretos e teste qualitativo com solução de AgNO3/HNO3 foi realizado para confirmar a ausência destes, e após isso, foi mantida em suspensão. Os compostos no estado sólido foram preparados pela mistura dos respectivos carbonatos metálicos com o ácido 2-metoxibenzóico (2-MeO-HBz). A suspensão aquosa foi aquecida lentamente próximo da ebulição até neutralização total dos carbonatos. As soluções resultantes depois de arrefecidas foram mantidas em banho de gelo para recristalizar o ácido em excesso e filtradas. Assim, as soluções aquosas dos metoxibenzoatos metálicos foram concentradas em banho maria e o precipitado seco resultante deste processo colocado em um dessecador contendo cloreto de cálcio. O composto de cobre devido a sua baixa solubilidade foi preparado pela adição lenta com gotejamento contínuo de solução do 2-metoxibenzoato de sódio 0.1 mol L-1 à solução de sulfato de cobre, até a total precipitação do íon cobre e o precipitado lavado com água destilada para eliminação do íon sulfato e teste qualitativo de confirmação realizado com BaCl2 0.1 mol L-1, em seguida filtrada em papel de filtro Whatman 40 e o precipitado após seco foi colocado em dessecador contendo cloreto de cálcio. Os compostos sintetizados foram investigados por meio de espectroscopia de infravermelho, difratometria de raio X pelo método do pó, termogravimetria e análise térmica diferencial simultânea (TG-DTA), termogravimetria, termogravimetria derivada (TG/DTG), calorimetria exploratória diferencial (DSC) e outros métodos de análise.
Carbonates of Mn (II), Co (II), Ni (II), Cu (II) and Zn (II) were prepared by adding slowly with continuous stirring saturated sodium hydrogen carbonate solution to the corresponding metal chloride solutions (except copper), until total precipitation of the metal ions. The precipitates were washed with distilled water until elimination of chloride ions (qualitative test with AgNO3/HNO3 solution) and maintained in aqueous suspension. olid state Mn (II), Co (II), Ni (II) and Zn (II) compounds were prepared by mixing the respective metal carbonates with 2-methoxybenzoic acid 99% (2-MeO-HBz) obtained from Aldrich, in slight excess. The aqueous suspension was heated slowly up to near ebullition, until total neutralization of the respective carbonates. The resulting solutions after cooled were maintained in an ice bath to recrystallize the acid in excess and filtered through a Whatman nº 40 filter paper. Thus, the aqueous solutions of the respective metal 2-methoxybenzoates were evaporated in a water bath until near dryness and kept in a desiccator over calcium chloride. The copper compound due to its low solubility was prepared by adding slowly, with continuous stirring, the aqueous solution of Na-2-MeO-Bz 0.1 mol L-1 to the respective metal sulphate solution, until total precipitation of the metal ions. The precipitate was washed with distilled water until elimination of the sulphate ion, filtered through and dried on Whatman no42 filter paper, and kept in a desiccator over anhydrous calcium chloride, under reduced pressure to constant mass. The compounds were investigated by means of infrared spectroscopy, X-Ray powder diffractometry, simultaneous thermogravimetry and differential thermal analysis (TG-DTA), Thermogravimetry derivative termogravimetry (TG/DTG), differential scanning calorimetry (DSC) and other methods of analysis.
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Vallejo, Adriana Cossu [UNESP]. "Síntese, caracterização e estudo do comportamento térmico dos 3-metoxibenzoatos de Mn(II), Co(II), Ni(II), Cu(II) e Zn(II), no estado sólido." Universidade Estadual Paulista (UNESP), 2004. http://hdl.handle.net/11449/97870.
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Os 3-metoxibenzoatos de Mn (II), Co (II), Ni (II), Cu (II) e de Zn (II), foram preparados fazendo-se reagir os respectivos carbonatos básicos com ácido 3-metoxibenzoico, ambos em suspensão aquosa à temperatura de ebulição. Os compostos assim obtidos foram estudados através da complexometria com EDTA, Termogravimetria (TG) e difratometria de raios X pelo método do pó. As curvas TG foram obtidas em atm de ar sintético e em cadinho de Pt para a amostra e referencia. Os resultados obtidos por termogravimetria (TG), complexometria com EDTA, possibilitaram estabelecer a estequiometria e o grau de hidratação dos compostos, que apresentaram fórmula geral: M(3-MeO-BZ) 2 nH2O com n= 0,5; 1,0;1,5 e 2,0. As curvas TG também permitiram verificar a estabilidade térmica, bem como o processo de decomposição térmica, destes compostos. Os difratogramas de raios X, pelo método do pó, mostraram que todos os compostos possuem estrutura cristalina, com exceção do composto níquel, obtidos no estado não cristalino.
The 3-methoxybenzoates of Mn (II), Co (II), Ni (II), Cu (II) and Zn (II) were prepared by reacting the respective basic carbonates with methoxybenzoates acid, both in aqueous suspension in a heating temperature. The compounds therefore obtained were studied by complexometric (EDTA), thermogravimetry, derivative thermogravimetry and differential thermal analysis (TG. DTG, DTA) and X-Ray diffractometry. The curves (TG) were obtained in atmosphere synthetic air and in Platinum crucible as samples and references. The results obtained by thermogravimetry (TG) and complexometric (EDTA) enabled to establish the stoichiometry and the hydration degree of these compounds which presented the general formula: M(3-MeO-BZ)2 nH2O with n=0,5; 1,0; 1,5 and 2,0. Also the curves (TG) permitted to verify as the thermal stability as the decomposition process of these compounds. The X-Ray powder patterns made possible to show that all the compounds had crystalline structure, except the Nickel (II) compound, shapeless by itself.
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Ferreira, Juliana Aparecida. "Desenvolvimento de estratégias para a determinação espectrofotométrica sequencial em fluxo de Co (II) e Mn (II)." Universidade Federal de São Carlos, 2009. https://repositorio.ufscar.br/handle/ufscar/6428.
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Previous issue date: 2009-07-24Financiadora de Estudos e Projetos
In this study a kinetic-spectrophotometric method was developed for sequential determination of Co and Mn in pharmaceutical samples. The method was based on the catalytic effect of the analytes in the oxidation reaction of Tiron by H2O2 in basic medium. In the case of Mn it was employed the activator reagent 2,2-bipyridine to effective catalysis. The FIA system was projected taking into account the catalytic properties of each analyte in the indicator reaction. Two factorial designs were applied, initially, a fractionary factorial design 29-5 followed by a complete factorial design 23 to select the important variables, and then a factorial design 22 + central point + star for optimizing of FIA system. Fractionary factorial designs 27-2 were applied in the study of possible interferents for Co and Mn. The main interferents were mathematically described using factorial + central point + star designs. The pharmaceutical samples were digested by concentrated HNO3 in digestor block. To evaluate the accuracy of the developed method, samples (n=3) were analyzed by FS-FAAS and based on the determination concentrations, these were diluted to posterior analysis aplyingby the developed method. Limits of detection (LOD) and quantification (LOQ) for FS-FAAS were 3.9 and 13.2 μg L-1 for Co; 110.0 and 366.0 μg L-1 for Mn, respectively. To developed method the LOD and LOQ were 0.055 and 0.18 μg L-1 for Co, 9.76 and 32.5 μg L-1 for Mn, respectively. Comparison between the two methods was evaluated by paired t-test. At 99% confidence level, the values did not differ statistically for Co. However, for Mn, the concentration values agreed but this data cannot be statistically confirmed due to differences of standard deviations of the two methods. The repeatability was 3.2% for Co and 8.0% for Mn. The sampling frequency was 25 samples h-1.
Neste trabalho desenvolveu-se um método cinético-espectrofotométrico visando a determinação sequencial de Co e Mn em amostras farmacêuticas. O método foi baseado no efeito catalítico dos analitos na reação de oxidação do Tiron (3,5 dihidroxi-1,3-ácido benzenossulfônico-sal dissódico monohidratado [(HO)2C6H2(SO3Na)2.H2O]) pelo H2O2 em meio básico. No caso do Mn foi empregado o reagente ativador 2,2-bipiridina para a efetiva catálise. O sistema FIA foi elaborado com base nas propriedades catalíticas de cada analito na reação indicadora. Foram realizados dois planejamentos fatoriais, inicialmente um fracionário 29-5 e depois um 23, para triagem das variáveis, seguido de um 22 + ponto central + estrela para a devida otimização das mesmas no sistema em fluxo. Planejamentos fatoriais fracionários 27-2 foram realizados para o estudo de possíveis interferentes para Co e Mn; e posteriormente, a porcentagem de interferência foi descrita através de modelos matemáticos construídos a partir de planejamentos do tipo fatorial + ponto central + estrela. As amostras farmacêuticas foram digeridas com HNO3 concentrado em bloco digestor. Para avaliar a exatidão do método desenvolvido, as amostras (n=3) foram analisadas por FS-FAAS e a partir das concentrações obtidas, estas foram diluídas para posterior análise no método desenvolvido. Os limites de detecção e quantificação para FS-FAAS foram 3,9 e 13,2 μg L-1 para Co, 110,0 e 366,0 μg L-1 para Mn, respectivamente. No caso do método desenvolvido, os limites de detecção e quantificação foram 0,055 e 0,18 μg L-1 para Co, 9,76 e 32,5 μg L-1 para Mn, respectivamente. A comparação entre os dois métodos foi realizada através do teste-t pareado. No caso do Co, ao nível de confiança 99% os valores não diferiram estatisticamente. Já para o Mn os valores de concentração obtidos também foram concordantes entre si, apesar deste fato não poder ser comprovado estatisticamente devido à diferença de desvios-padrão dos dois métodos. A repetibilidade foi de 3,2% para Co e 8,0% para Mn. A frequência de amostragem foi de 25 amostras h-1.
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Lima, Gilvan Epifânio Silva. "Avaliação da atividade catalítica de novos complexos à base de Co(II), Mn(II) e Fe(II) para polimerização oxidativa." Universidade Federal de Alagoas, 2013. http://www.repositorio.ufal.br/handle/riufal/1982.
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The main aim of this study was to develop new catalysts for the oxidative polymerization of vegetable oils, and may be applied in the coatings industry, in order to control the cure process oil resins, without compromising the final quality of the material. This study was conducted in two parts. At first, the nitrogen-based ligands 2,2'-bipyridyl, 4,4'-dimethyl-2,2'-bipyridyl, 6,6'-dimethyl-2,2'-bipyridyl, 1,10-
phenanthroline, 4-methyl-1,10-phenanthroline, 5,6-dimethyl-1,10-phenanthroline were coordinated to the metal center of the catalyst precursor, producing new complexes based on cobalt, manganese and iron. The right ratio of ligands attached at the metal center was determined by ultraviolet spectroscopy, and adopted during the oxidative polymerization reactions of linseed oil in order to evaluate catalytic
properties by the evolution of the viscosity of the reaction medium. Additionally, infrared spectroscopy was used to verify the evolution of some chemical groups during the polymerization process. It was possible to observe that the manganese and iron catalytic systems, modified by the presence of the nitrogen-based ligands, were more efficient than those of based on cobalt. The addition of 5,6-dimethyl-1,10-phenanthroline in the reaction mixture led to better results in terms of increase of the viscosity rate, probably due to electronic effects, or due the compatibility of the catalyst-substrate. The adoption of nitrogen-based ligands in the reaction medium, in order to accelerate the oxidative polymerization process is very promising.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O objetivo principal desse estudo é o desenvolvimento de novos catalisadores para a polimerização oxidativa, que possam futuramente, ser aplicados na indústria de revestimentos, afim de acelerar o processo de polimerização oxidativa de óleos vegetais, sem comprometer a qualidade final do material. Este estudo foi conduzido em duas etapas. Na primeira, os ligantes nitrogenados 2,2’-dipiridil, 4,4’-imetil 2,2’-dipiridil, 6,6’-dimetil 2,2’-dipiridil; 1,10’-fenantrolina, 4-metil-1,10’-fenanatrolina e 5,6-metil-1,10’-fenantrolina foram coordenados ao precursores metálicos, produzindo assim os novos catalisadores a base de cobalto, manganês e ferro. A estequiometria apropriada para obtenção dos complexos modificados foi determinada com sucesso, através da espetroscopia na região do ultra-violeta visível. Em uma segunda etapa, esses complexos foram empregados em reações de polimerização oxidativa do óleo de linhaça, a fim de avaliar sua atividade catalítica utilizando o acompanhamento da evolução da viscosidade e complementando com a espectroscopia no infravermelho médio. Os principais resultados desse trabalho são a obtenção de três famílias de complexos, a base de cobalto, manganês e ferro, modificados com ligantes nitrogenados. Na maioria dos casos, os sistemas catalíticos a base de manganês e ferro modificados, apresentaram eficiência superior àqueles de cobalto. No caso dos ligantes fenantrolínicos, a presença do ligante contendo duas metilas conduziu a melhores resultados, provavelmente devido a efeitos eletrônicos ou de compatibilidade entre catalisador-substrato A estratégia de utilização de ligantes nitrogenados mostrou-se muito eficaz, no sentido de acelerar a reação de polimerização oxidativa.
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Schmidt, Thomas. "Optische Untersuchung und Kontrolle der Spindynamik in Mn dotierten II-VI Quantenpunkten." kostenfrei, 2009. http://www.opus-bayern.de/uni-wuerzburg/volltexte/2009/3603/.
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Carmo, Sângela Nascimento do. "Extração seletiva de Mn(II) utilizando sementes de Moringa oleífera como bioadsorvente." Universidade Federal de Uberlândia, 2014. https://repositorio.ufu.br/handle/123456789/17422.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorIn this study, a method using Moringa oleifera seeds as bioadsorbents for selective retention of Mn(II) was developed. The variables studied were pH, particle size, mass and contact time, being the pH the most important variable in the separation process. After, adsorption isotherms were constructed in order to evaluate the adsorptive capacity of the material and the characteristics of the adsorption process. The results were: pH 3,0, particle size ≤ 180 μm, adsorbent mass equal to 1.0 g and time of contact 15 minutes. Data of Mn(II) removal were adjusted to Langmuir model, obtaining qmax (mg g -1) of 10.35. Characterization techniques such as infrared spectroscopy, thermal analysis and scanning electron microscopy and theory adsorption multielement were used in physic chemical evaluation of Moringa oleífera seeds. The method was applied to the selective extraction of manganese in water samples and the accuracy of the method was evaluated using reference material (drinking water reference certified material, APS 1075). The values obtained showed high agreement with the certified values, demonstrating the efficiency of the proposed method.
Nesse estudo é apresentado o desenvolvimento de um método utilizando sementes de Moringa oleífera como bioadsorvente na retenção seletiva de Mn(II). Foram estudadas as variáveis pH, granulometria, massa e tempo de agitação sendo o pH a variável determinante para o processo de separação. Posteriormente, foram construídas isotermas de adsorção, com o objetivo de avaliar a capacidade adsortiva do material bem como as características do processo de adsorção. Os resultados obtidos foram: pH 3,0, granulometria ≤ 180 μm, massa do adsorvente 1,0 g e tempo de contato de 15 minutos. Os dados da remoção de Mn(II) se ajustaram ao modelo de Langmuir, obtendo-se qmax (mg g-1) de 10,35. Técnicas de caracterização incluindo espectrometria de infravermelho, análise termogravimétrica, microscopia eletrônica de varredura e teoria de adsorção multielementar foram utilizadas na avaliação físico-química das sementes de Moringa oleífera. O método foi aplicado para extração seletiva de manganês inorgânico em amostras de água e a exatidão do método avaliada a partir da análise de material de referência (material certificado de referência para água de bebidas, APS 1075). Os valores encontrados apresentaram elevada concordância com os valores certificados, evidenciando a eficiência do método proposto.
Mestre em Química
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Goveia, Danielle [UNESP]. "Preparação, caracterização e aplicação de membranas celulósicas organomodificadas no estudo da labilidade de Cu(II), Mn(II), Ni(II) e Cd(II) em sistemas aquáticos." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/97868.
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Neste trabalho, membranas poliméricas de acetato de celulose foram preparadas pelo procedimento de inversão de fase e juntamente com filtros de papel JP41 (Jprolab- Procedência Alemã), foram organomodificados com tetraetilortosilicato (TEOS) e 3-aminopropiltrietoxisilano (3-APTS), visando o desenvolvimento de um novo procedimento analítico para especiação in-situ de metais lábeis e inertes em sistemas aquáticos. Parâmetros que exercem influência na labilidade do íon metálico, como pH, tempo de complexação, concentração e características de matéria orgânica foram estudadas em laboratório usando testes de remoção de metais. Os tempos de equilíbrio de complexação na membrana polimérica indicaram uma cinética lenta para os íons metálicos Mn(II) e Ni(II), mais rápidas para Cu(II) e Cd(II) com uma baixa recuperação de cátions metálicos. Os resultados com os testes utilizando filtros de papel organomodificados apresentaram uma cinética mais baixa para íons Cu(II) em comparação com Ni(II), Mn(II) e Cd(II). A labilidade relativa observada para cátions metálicos complexados em substâncias húmicas aquáticas (SHA) usando filtros de papel organomodificados foi Cu>>Cd>Ni>Mn. Os valores de pH, características estruturais e concentração de SHA influenciam fortemente na labilidade dos metais estudados. Os resultados obtidos mostraram que a utilização de filtros de papel organomodificados pode ser uma alternativa interessante e promissora pra a caracterização in-situ de metais lábeis/inertes em sistemas aquáticos.
In this work, cellulose acetate polymeric membranes have been prepared by the procedure of phase inversion and together with paper filters JP41 (Jprolab- German origin), have been organomodified with tetraethylortosilicate (TEOS) and aminopropyltriethoxysilane (3-APTS), aiming the development of a new analytical procedure for in-situ especiation of labile and inert metallic species in aquatic systems. Parameters that exert influence on the metal lability, as pH, complexation time, concentration and characteristics of organic matter were studied in laboratory using tests of metal recovery. The equilibrium times of complexation in the polymeric membrane indicated slow kinetic for metallic ions Mn(II) and Ni(II), faster for Cu(II) and Cd(II) and a low metal removal. The results with the tests using organomodified paper filters showed lowest kinetic for ions Cu(II) in comparison with Ni(II), Mn(II) and Cd(II). The relative lability observed for metallic cations complexed in aquatic humic substances (HAS) using the paper filters was Cu>>Cd>Ni>Mn. The pH values, structural characteristics and concentration of AHS exert strong influence on the lability of studied metals. The results obtained showed that the utilization of organomodified filter papers can be an interesting and promising alternative for insitu characterization of metal lability/inertness in aquatic systems.
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Goveia, Danielle. "Preparação, caracterização e aplicação de membranas celulósicas organomodificadas no estudo da labilidade de Cu(II), Mn(II), Ni(II) e Cd(II) em sistemas aquáticos /." Araraquara : [s.n.], 2006. http://hdl.handle.net/11449/97868.
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Resumo: Neste trabalho, membranas poliméricas de acetato de celulose foram preparadas pelo procedimento de inversão de fase e juntamente com filtros de papel JP41 (Jprolab- Procedência Alemã), foram organomodificados com tetraetilortosilicato (TEOS) e 3-aminopropiltrietoxisilano (3-APTS), visando o desenvolvimento de um novo procedimento analítico para especiação "in-situ" de metais lábeis e inertes em sistemas aquáticos. Parâmetros que exercem influência na labilidade do íon metálico, como pH, tempo de complexação, concentração e características de matéria orgânica foram estudadas em laboratório usando testes de remoção de metais. Os tempos de equilíbrio de complexação na membrana polimérica indicaram uma cinética lenta para os íons metálicos Mn(II) e Ni(II), mais rápidas para Cu(II) e Cd(II) com uma baixa recuperação de cátions metálicos. Os resultados com os testes utilizando filtros de papel organomodificados apresentaram uma cinética mais baixa para íons Cu(II) em comparação com Ni(II), Mn(II) e Cd(II). A labilidade relativa observada para cátions metálicos complexados em substâncias húmicas aquáticas (SHA) usando filtros de papel organomodificados foi Cu>>Cd>Ni>Mn. Os valores de pH, características estruturais e concentração de SHA influenciam fortemente na labilidade dos metais estudados. Os resultados obtidos mostraram que a utilização de filtros de papel organomodificados pode ser uma alternativa interessante e promissora pra a caracterização "in-situ" de metais lábeis/inertes em sistemas aquáticos.Abstract: In this work, cellulose acetate polymeric membranes have been prepared by the procedure of phase inversion and together with paper filters JP41 (Jprolab- German origin), have been organomodified with tetraethylortosilicate (TEOS) and aminopropyltriethoxysilane (3-APTS), aiming the development of a new analytical procedure for "in-situ" especiation of labile and inert metallic species in aquatic systems. Parameters that exert influence on the metal lability, as pH, complexation time, concentration and characteristics of organic matter were studied in laboratory using tests of metal recovery. The equilibrium times of complexation in the polymeric membrane indicated slow kinetic for metallic ions Mn(II) and Ni(II), faster for Cu(II) and Cd(II) and a low metal removal. The results with the tests using organomodified paper filters showed lowest kinetic for ions Cu(II) in comparison with Ni(II), Mn(II) and Cd(II). The relative lability observed for metallic cations complexed in aquatic humic substances (HAS) using the paper filters was Cu>>Cd>Ni>Mn. The pH values, structural characteristics and concentration of AHS exert strong influence on the lability of studied metals. The results obtained showed that the utilization of organomodified filter papers can be an interesting and promising alternative for "insitu" characterization of metal lability/inertness in aquatic systems.
Orientador: André Henrique Rosa
Coorientador: Ademir dos Santos
Banca: Raquel Fernandes Pupo Nogueira
Banca: Jorge César Masini
Mestre
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SILVA, RENATA SOBRAL. "MN(II) AND CO(II) COMPLEXES WITH THIOSEMICARBAZONES AND FLUORQUINOLONES: SYNTHESIS, SPECTROSCOPIC AND ELECTROCHEMICAL STUDIES AND BIOLOGICAL ACTIVITY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=14131@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Tiossemicarbazonas e fluorquinolonas são compostos que apresentam uma grande diversidade de aplicações farmacológicas. Este trabalho compreende um estudo de tiossemicarbazonas e seus complexos de Mn(II) e Co(II) com potencial ação antiparasitária e antitumoral e de complexos de Mn(II) e Co(II) de fluorquinolonas com atividade antimicrobiana. N(4)-metil tiossemicarbazonas derivadas de 4-nitrobenzaldeído (H4NO2Fo4M), 4-nitroacetofenona (H4NO2Ac4M) e 4-nitrobenzofenona (H4NO2Bz4M) e seus complexos de Mn(II) e Co(II), [Mn(H4NO2Fo4M)2Cl2], [Mn(H4NO2Ac4M)2Cl2], [Mn(H4NO2Bz4M)2Cl2], [Co(H4NO2Fo4M)2Cl2], [Co(H4NO2Ac4M)2Cl2], [Co(H4NO2Bz4M)2Cl2], foram obtidos e caracterizados. A estrutura cristalográfica de N(4)-metil 4-nitrobenzaldeído tiossemicarbazona (H4NO2Fo4M) foi determinada. Estudos eletroquímicos mostram que o radical Ar-NO2, um dos intermediários no mecanismo de ação de drogas antitripanossoma, forma-se em torno de -1,0 V nas tiossemicarbazonas livres e nos complexos de Mn(II), sugerindo potencial atividade anti-tripanossoma. A fluorescência natural observada para as N(4)-metil nitrotiossemicarbazonas e de seus complexos de Mn(II) e Co(II) pode vir a servir para identificar e monitorar a presença dessas espécies no meio biológico. A toxicidade das tiossemicarbazonas e de seus complexos de Mn(II) frente à Artemia salina foi estudada como um préscreening para sua ação antitumoral. Os valores de CL50;48h (concentração letal para 50% da população exposta à droga durante 48 horas) obtidos indicam que esses compostos têm atividade citotóxica, sugerindo que poderiam igualmente apresentar ação antitumoral. Um dos grandes problemas com antibióticos empregados na clínica é o aparecimento de resistência às drogas e assim a busca de novos fármacos ativos é de extrema relevância. Em muitos casos, mecanismos de resistência celular não reconhecem complexos metálicos, embora reconheçam os ligantes. Preparamos então complexos de Mn(II) e Co(II) de norfloxacina e esparfloxacina, [MnCl2(NOR)(H2O)2], [CoCl2(NOR)(H2O)2], [MnCl2(ESPAR)(H2O)2] e [CoCl2(ESPAR)(H2O)2], e testamos sua atividade em cepas de Staphylococcus aureus sensíveis e resistentes às drogas livres. Em resumo, acreditamos que com esse trabalho contribuímos para um melhor conhecimento da química de tiossemicarbazonas e fluorquinolonas e de suas diversas propriedades farmacológicas.
Thiosemicarbazones and fluorquinolones are a class of compounds presenting a wide range of pharmacological activities. In the present work a study of thiosemicarbazones and their Mn(II) and Co(II) complexes with potential anti parasite and antitumoral activities was carried out along with an investigation of Mn(II) and Co(II) complexes of norfloxacin and sparfloxacin with antimicrobial activity. N(4)-methyl thiosemicarbazones derived from 4-nitrobenzaldehyde (H4NO2Fo4M), 4-nitroacetophenone (H4NO2Ac4M) and 4-nitrobenzophenone (H4NO2Bz4M) and their Mn(II) and Co(II) complexes, [Mn(H4NO2Fo4M)2Cl2], [Mn(H4NO2Ac4M)2Cl2], [Mn(H4NO2Bz4M)2Cl2], [Co(H4NO2Fo4M)2Cl2], [Co(H4NO2Ac4M)2Cl2], [Co(H4NO2Bz4M)2Cl2], were obtained and characterized. The crystal structure of H4NO2Fo4M has been determined. Electrochemical studies have shown that the Ar-NO2, one of the proposed intermediates in the mechanism of action of nitro-containing anti-trypanosomal drugs, is formed at approximately -1.00 V in the free thiosemicarbazones as well as in their corresponding Mn(II) complexes, suggesting their potential to act as antitrypanosomal drugs. The natural fluorescence of H4NO2Fo4M, H4NO2Ac4M, H4NO2Bz4M and Mn(II) and Co(II) complexes provides a way to identify and to monitor their concentration in biological systems. The toxicity of the thiosemicarbazones and their Mn(II) complexes against Artemia salina was assayed as a prescreening for antitumoral action. The low values of CL50;48h obtained for the studied compounds in this assay indicate that they could present antineoplastic properties. One of the major problems in the clinical treatment of infection by bacteria is the appearance of resistance and therefore the search for new drugs is extremely important. In many cases resistance mechanisms recognize the ligand but cannot recognize its metal complex. In the present work Mn(II) and Co(II) complexes of norfloxacin and sparfloxacin, [MnCl2(NOR)(H2O)2], [CoCl2(NOR)(H2O)2], [MnCl2(ESPAR)(H2O)2] and [CoCl2(ESPAR)(H2O)2] were obtained and their antibacterial activity against Staphylococcus aureus has been tested. We believe that this work contributes for a better knowledge of the chemistry of thiosemicarbazones and fluorquinolones and their pharmacological properties.
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Santos, Elisama Vieira dos. "Adsor??o de Mn (II) e Zn (II) em solu??es aquosas usando perlita expandida revestida com quitosana." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17645.
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Previous issue date: 2011-07-05Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
In this work, chitosan was used as a coating of pure perlite in order to increase the accessibility of the groups OH- e NH2+the adsorptionof ions Mn2+ e Zn2+.The characterization results of the expanded perlite classified as microporous and whose surface area 3,176 m2 g-1after the change resulted in 4,664 m2g-1.From the thermogravimetry(TG) it was found that the percentage of coating was34,3%.The infrared analysis can prove the presence of groups Si-OH, Si-O e Al-O-Siresulting from the perlite and C=O, NH2and OH characterization of chitosan. The experiments on experiments on the adsorption of Mn and Zn were performed in the concentration range of10 a 50 mgL-1and the adsorption capacity inpH 5,8 e 5,2 was 19,49 and 23,09 mgg-1to 25 oC,respectively.The adsorption data were best fitted to Langmuir adsorption model to Langmuir adsorption model for both metalionsisindicative of monolayer adsorption. The kinetics of adsorption were calculated from the equation of Lagergren fitting the model pseudo-second-order for all initial concentrations, suggesting that adsorption of ions Mn2+ and Zn2+ follows the kinetics of pseudo-second-order and whose constant Speedk2(g/mg.min) are 0,105 e 3,98 and capacity and maximum removal qe 4,326 e 3,348,respectively.In this study we used a square wave voltammetry cathodic stripping voltammetry to quantify the adsorbed ions, and the working electrode glassy carbon, reference electrode silver / silver chloride and a platinum auxiliary electrode. The attainment of the peaks corresponding to ions Mn2+ and Zn2+ was evaluated in and electrochemical cell with a capacity of 30 mL using a buffer system (Na2HPO4/NaH2PO4)at pH 4 and was adjusted with solutionsH3PO4 0,1molL-1and NaOH 0,1 molL-1and addition of the analyte has been a cathodic peak in- 0,873 Vand detection limit of2,55x10-6molL-1para Zn.The dough used for obtaining the adsorption isotherm was 150 mg and reached in 120 min time of equilibrium for both metal ions.The maximum adsorption for 120 min with Mn concentration 20 mgL-1 and Zn 10 mgL-1,was91, 09 e 94, 34%, respectively
Nesse trabalho a quitosana foi utilizada como revestimento da perlita expandida pura com o objetivo de aumentar a acessibilidade dos grupos OH- e NH2+ na adsor??o dos ?ons Mn2+ e Zn2+. A perlita expandida foi classificada como microporoso com uma ?rea superficial de 3,176m2 g-1 e ap?s modifica??o resultou em 4,664m2 g-1. A partir da Termogravimetria (TG) verificou-se que o percentual de revestimento foi de 37,5%. A an?lise de infravermelho comprovou a presen?a dos grupos Si-OH, Si-O e Al-O-Si decorrentes da perlita e C=O, NH2 e OH caracter?sticos da quitosana. Os experimentos na adsor??o de Mn2+ e Zn2+ foram realizados no intervalo de concentra??o de 10 a 50 mg L-1 e acapacidade de adsor??o em pH 5,2 e 5,8 foi de 23,09 e 19,49 mg g-1 a 25 oC, respectivamente. Os dados de adsor??o se ajustaram melhor ao modelo de adsor??o de Langmuir para ambos os c?tions met?licos sendo indicativo de adsor??o f?sica em monocamada.As constantes de velocidade de adsor??o foram calculadas a partir da equa??o Lagergren se ajustando ao modelo de pseudo-segunda-ordem para todas as concentra??es iniciais, sugerindo que a adsor??o dos ?ons Mn2+ e Zn2+ segue a cin?tica de pseudo-segunda-ordem e cujas constantes de velocidade k2(g/mg.min) s?o 0,105 e 3,98 e capacidade m?xima de remo??o qe 4,326 e 3,348 mg g-1, respectivamente. Utilizou-se a voltametria de onda quadrada de redissolu??o cat?dica para a quantifica??o dos ?ons adsorvidos, com o eletrodo de trabalho de carbono v?treo, eletrodo de refer?ncia prata/cloreto de prata e um eletrodo auxiliar de platina. A obten??o dos picos correspondente aos ?ons Mn2+ e Zn2+ foi avaliado em uma c?lula eletroqu?mica com capacidade para 30 mL utilizando um sistema tamp?o (Na2HPO4/NaH2PO4) cuja concentra??o 0,1 mol L-1em pH 4, sendo ajustado com solu??es H3PO4 0,1 mol L-1e NaOH 0,1 mol L-1e adi??o do analito, tendo verificado um pico cat?dico em 0,873 V com limite de detec??o de Mn 7,76x10-7 mol L-1 e um pico an?dico de -1,1 V e limite de detec??o de 2,55x10-6mol L-1 para Zn2+.A massa utilizada para a obten??o das isotermas de adsor??o foi de 150 mg, tendo atingido o tempo de equil?brio de 120 min para ambos ?ons met?licos. A m?xima adsor??o em 120 min para Mn2+ com concentra??o de 20 mg L-1 e Zn 10 mg L-1, foi de 91,09 e 94,34% ,respectivamente
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Bonafim, Suéli. "Estudo de equilíbrio de possíveis ligantes inibidores da enzima integrase com os íons Mg (II) e Mn(II)." reponame:Repositório Institucional da UFSC, 2015. https://repositorio.ufsc.br/xmlui/handle/123456789/159643.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, 2015.Made available in DSpace on 2016-03-01T04:03:24Z (GMT). No. of bitstreams: 1 337289.pdf: 1350786 bytes, checksum: 349bc4f71bc6317404334cc4b9010aa0 (MD5) Previous issue date: 2015
A Síndrome da Imunodeficiência Adquirida (AIDS) é uma doença causada pelo Vírus da Imunodeficiência Humana (HIV). A epidemia de infecção pelo HIV é considerada uma das maiores pandemias já observada na história. A integrase (IN) é uma enzima essencial no ciclo de vida do HIV e sua inibição é um alvo atrativo para o desenvolvimento de novos fármacos. Compostos dicetônicos e com grupos catecol vem sendo validados como potenciais inibidores da integrase, portanto, o foco desde projeto foi estudar os equilíbrios envolvidos entre dez ligantes contendo grupos dicetônicos e grupos catecol com os íons Mg(II) e Mn(II) a fim de verificar se o mecanismo de ação destes possíveis fármacos envolve a complexação com sítio ativo da enzima integrase.Os equilíbrios de formação dos complexos entre os ligantes 5-CITEP, CG-I-83D, CG-I-160, CG-II-38B, CG-II-51, CG-II-133A, CG-II-135A, GS-9137, CG-I-154 e CG-I-139 e os íons Mg(II) e Mn(II) foram determinados em solução através de titulação potenciométrica e espectroscopia UV-Vis.Para o sistema com o íon Mg(II), ligantes como CG-I-83D, CG-II-51, CG-I-160, CG-I-133A, CG-I-135A, CG-I-139 e CG-I-154 foram os que apresentaram mais afinidade com o metal, formando diferentes espécies do complexo metálico ao longo da faixa de pH, especialmente em pH neutro.Os estudos com o íon Mn(II) revelaram que ligantes como 5CITEP, CH-I-38B e CH-I-135A tem mais afinidade com este metal em diferentes faixas de pH. O ligante GS-9137 não formou expressivas quantidades de complexos com ambos os íons Mg(II) e Mn(II). As espécies formadas com Mg(II) encontram-se na faixa de pH alcalina, não servindo para o propósito biológico do ligante. Para o sistema com Mn(II) houve a formação de espécies em pH neutro, porém, em pequena quantidade.
Abstract : The Acquired Immune Deficiency Syndrome (AIDS) is a disease caused by the Human Immunodeficiency Virus (HIV). The epidemic of HIV infection is considered one of the largest pandemics ever seen in history. Integrase (IN) is an essential enzyme in the life cycle of HIV and its inhibition is an attractive target for the development of new drugs. Dicetonic compounds and molecules containing catechol group has been validated as potential integrase inhibitors, therefore the goal in this project was focused in equilibrium studies involving dicetonics and catechol compounds of ten ligands with Mg(II) ions and Mn(II). The equilibrium of the complexes formation between the ligands 5CITEP, CG-I-83D, CG-II-51, CG-II-38B, CG-II-51, CG-II-133A, CG-II-135A, GS -9137, CG-I-154 and CG-I-139 ions and Mg(II) and Mn(II) in solution were determined by potentiometric titration and UV-Vis spectroscopy. For the system with Mg(II) ion, binders such as CG-I-83D, GC-II-51, GC-I-160, CG-I-133A, CG-II-135A, CG-I-139 and CG-I-154 were those that had an affinity for the metal, forming different species of the metal complex throughout the pH range, especially at neutral pH. Studies with Mn(II) ion revealed that ligands such as 5CITEP, CG-II-38B and CG-II-135A have affinity for this metal in different pH ranges. GS-9137 did not form complexes with significant amounts of both Mg(II) ions and Mn(II). The species formed with Mg(II) are in the alkaline pH range, not intended for the purpose of ligands with biological applications. For the system with Mn(II) species were formed at neutral pH, but in small quantities.
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Tselepis-Loertscher, Cynthia. "INVESTIGATION OF HETEROGENEOUS OXIDATION OF Mn(II) AND OXIDE FORMATION ON GOETHITE SURFACES." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1323891537.
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Clement, Brian Gregory. "Biological Mn(II) oxidation in freshwater and marine systems new perspectives on reactants, mechanisms and microbial catalysts of Mn cycling in the environment /." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3214114.
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Thesis (Ph. D.)--University of California, San Diego, 2006.Title from first page of PDF file (viewed January 28, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Reaney, Stephen Howard. "Manganese toxicity : an in vivo and in vitro investigation of the relative cellular and neurotoxic effects of Mn(II) and Mn(III) exposure /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2003. http://uclibs.org/PID/11984.
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Rahim, Abdur 1980. "SiO2/MPc/C e electrically conductive ceramic material (Pc: phthalocyanine, M=Mn(II), Co(II), Cu(II)) a new substrate for the preparation of electrochemical sensors and biosensors = Material cerâmico eletricamente condutor SiO2/MPc/C (Pc: ftalocianina, M=Mn(II), Co(II), Cu(II) um novo substrato para o preparo de sensores e biosensores eletroquímicos." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248359.
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Orientador: Yoshitaka GushikemTexto em inglês
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: Este trabalho descreve as sínteses, caracterizações e as aplicações dos materiais carbono cerâmicos mesoporosos identificados como: SiO2/20wt%C (SBET= 160 mg) e SiO2/50wt%C (SBET= 170 mg), em que C corresponde ao carbono grafite. Tais materiais foram preparados através do método sol-gel e empregados como matrizes para o desenvolvimento de sensores e biosensores eletroquímicos. Imagens obtidas através da microscopia eletrônica de varredura (MEV) acoplada com a espectrosocopia de energia dispersiva (EDS) mostraram que, com relação as resoluções utilizadas, não foram detectadas segregação de fases. Os materiais que contem 20 e 50 wt% de C apresentaram condutividades elétricas de 9,2 x 10 S cm e 0,49 S cm, respectivamente. Esses materiais foram utilizados como matrizes para suportar ftalocianinas de: cobalto (CoPc), cobre (CuPc) e manganês (MnPc), as quais foram preparadas in situ ao longo de suas superfícies de forma que fosse assegurada dispersão homogênea dos complexos eletroativos nos poros das matrizes. As densidades superficiais da ftalocianina de cobalto em ambas as superfícies da matriz foram: 0,014 mol cm e 0,015 mol cm, para os materiais contendo 20 e 50 % m/m de C, respectivamente. Foram empregados como eletrodos de trabalho pastilhas preparadas a partir dos eletrodos carbono cerâmicos, considerando-se os seguintes materiais: SiO2/C/CoPc, SiO2/C/CuPc e SiO2/C/MnPc. A técnica de XPS foi usada para determinar as proporções de Mn/Si atómicos dos materiais MnPc modificados. O material SiO2/C/CoPc foi testado como um sensor de ácido oxálico e de oxigenio, e os materiais e SiO2/C/CuPc e SiO2/C/MnPc foram testados como sensores para a dopamina e nitrito, respectivamente. Esses materiais tem se mostrado como alternativas promissoras para o desenvolvimento de sensores eletroquímicos e de biosensores, atuando como substratos robustos e versáteis para a construção de novos eletrodos carbono cerâmicos.
Abstract: This work describes the synthesis, characterization and applications of mesoporous carbon ceramic materials identified as: SiO2/20wt%C (SBET = 160 mg) and SiO2/50wt%C (SBET= 170 mg), where C represents the carbon graphite. These materials were prepared by the sol-gel method and used as support for the development of electrochemical sensors and biosensors. Images obtained by scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) showed that, within the magnification used, no phase segregation was detectable. The materials containing 20 and 50 wt% of C presented electric conductivities of 9.2×10and 0.49 S cm, respectively. These materials were used as matrices to support manganese phthalocyanines (MnPc), cobalt phthalocyanines (CoPc), and copper phthalocyanines (CuPc), prepared in situ on their surfaces, to assure homogeneous dispersion of the electroactive complex in the pores of matrices. The surface densities of cobalt phthalocyanine on both matrix surfaces were: 0.014 mol cm and 0.015 mol cm, for materials containing 20 and 50% wt% of C, respectively. The pressed disk carbon ceramic electrode: SiO2/C/MnPc, SiO2/C/CoPc, and SiO2/C/CuPc were used as working electrode. XPS was used to determine the Mn/Si atomic ratios of the MnPc-modified materials. The material SiO2/C/CoPc was tested as a sensor for oxalic acid and oxygen and the materials SiO2/C/CuPc and SiO2/C/MnPc were tested as sensors for dopamine and nitrite, respectively. These materials have shown to be promising alternative in the development of electrochemical sensors and biosensor, acting as a robust and versatile conducting substrate for the construction of new carbon ceramic electrodes.
Doutorado
Quimica Inorganica
Doutor em Ciências
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Dewhirst, William Scott. "Mn(II) oxidation by HOCl in the presence of iron oxides : a catalyzing effect /." Thesis, This resource online, 1997. http://scholar.lib.vt.edu/theses/available/etd-08252008-162202/.
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Moreno, Ruben Gregorio Moreno. "Estudos de lesão ao DNA promovida pela autoxidação de S(IV) na presença de complexos de Cu(III)/tetraglicina. Efeito sinérgico de Ni(II), Co(II) e Mn(II)." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-04062007-032229/.
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O presente trabalho apresenta estudos de lesão em biomoléculas (DNA e 2\'-deoxiguanosina) induzida por Cu(III)/tetraglicina (Cu(III)/G4), radicais de óxidos de enxofre (SO3·-, SO4·-, SO5·-), HO· e HSO5-, espécies estas geradas durante a autoxidação de S(IV) na presença de Cu(II)/G4 ou Cu(II) (ausência de tetraglicina) e traços de um segundo íon metálico (Ni(II), Co(II) ou Mn(II)). A formação dos radicais SO3·- e HO· foi detectada pela técnica de ressonância paramagnética eletrônica (EPR). As técnicas de espectrofotometria e dicroísmo circular foram empregadas para avaliar a formação de Cu(III)/G4 em diferentes condições experimentais, na presença e ausência de S(IV), e a interação entre os complexos de cobre (II)/(III) e a molécula de DNA. A eficiência da formação de Cu(III) depende da acidez, concentração de S(IV) e dos tampões utilizados. A lesão no DNA plasmidial pUC19 foi verificada empregando-se a técnica de eletroforese em gel de agarose. A extensão da lesão no DNA depende da acidez, concentração de S(IV), tempo de incubação e da presença de um segundo íon metálico. Usando a técnica de cromatografia líquida de alta eficiência (HPLC) foi possível estudar a oxidação de 2\'-deoxiguanosina a 8-oxo-7,8-dihidro-2\'-deoxiguanosina na presença dos oxidantes fortes gerados durante a autoxidação de S(IV) catalisada por Cu(II)/G4. Um estudo comparativo do efeito de vários íons metálicos evidenciou o sinergismo de Cu(II) e traços de um segundo íon metálico (Ni(II), Co(II) ou Mn(II), complexados ou não com tetraglicina).The present work presents studies related to biomolecules damage (DNA and 2\'-deoxyguanosine) induced by Cu(III)/tetraglycine (Cu(III)/G4), oxysulfur radicals (SO3·-, SO4·-, SO5·-) and HSO5-, species generated during S(IV) autoxidation in the presence of Cu(II)/G4 or Cu(II) (absence of tetraglycine) and trace level of a second metal ion (Ni(II), Co(II) or Mn(II)). The formation of SO3·- and HO· radicals was detected by electronic paramagnetic resonance technique (EPR). Spectrophotometric and circular dichroism techniques were used to evaluate the Cu(III)/G4 formation in different experimental conditions, in the presence and the absence of S(IV), and the interaction of copper (II)/(III) complexes and DNA molecule. The effectiveness of Cu(III) formation depends on the acidity, S(IV) concentration, and buffers used. The damage on pUC 19 plasmid DNA was verified by agarose gel electrophoresis. The extent on the DNA damage was related to acidity, S(IV) concentration, incubation time and to the presence of a second metal ion. Using the high performance liquid chromatography technique (HPLC) it was possible to study the oxidation of 2\'-deoxyguanosine to 8-oxo-7,8-dihydro-2\'-deoxyguanosine in the presence of strong oxidants generated during the S(IV) autoxidation catalyzed by Cu(II)/G4. A comparative study of the effect of several metal ions showed the synergism of Cu(II) and traces of a second metal ion (Ni(II), Co(II) or Mn(II), as tetraglycine complexes or not).
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Hashimoto, Patrícia Kazuyo. "Complexos de Mn(II) e Fe(II) coordenados a bases de Schiff Bidentadas derivadas de cicloalquilaminas como mediadores da OMRP de acetato de vinila /." Presidente Prudente, 2018. http://hdl.handle.net/11449/154400.
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Orientador: Beatriz Eleutério GoiCoorientador: Valdemiro Pereira de Carvalho Júnior
Banca: Pedro Ivo da Silva Maia
Banca: Ana Maria Pires
Resumo: Nas últimas décadas, a polimerização radicalar controlada (CRP) tem se tornado muito importante, pois permite a síntese de macromoléculas de arquiteturas específicas com um controle sobre as propriedades químicas e físicas. Sendo assim, este trabalho apresenta a síntese de novos complexos de Mn(II) e Fe(II) coordenados à ligantes bases de Schiff bidentados, que são resultantes da condensação do salicilaldeído com as seguintes cicloalquilaminas: (1) Ciclopentilamina, (2) Cicloexilamina, (3) Cicloeptilamina e (4) Ciclooctilamina, de forma que estes possam ser utilizados como mediadores da polimerização radicalar mediada por organometálicos. Os ligantes foram caracterizados pelas seguintes técnicas: espectroscopia de ressonância magnética nuclear de hidrogênio (RMN de 1H), espectroscopia de absorção na região do ultravioleta-visível (UV-Vis) e espectroscopia vibracional na região do infravermelho (FTIR). Já os complexos de Mn(II) e Fe(II) foram caracterizados pelas técnicas de FTIR, UV-Vis, voltametria cíclica (VC) e ponto de fusão (p.f.). Os estudos cinéticos de polimerização foram realizados para os complexos de manganês e ferro. O complexo [MnIIbis(N-Salicilideno-Ciclopentilamina)], Mn(L1)2, apresentou um melhor controle na polimerização do acetato de vinila com menores valores de polidispersidade e a curva de massa molecular (Mn) mais próxima aos valores da curva teórica. Já os complexos de ferro mediadores apresentaram um comportamento mais similar, não havendo muita...
Abstract: In the last decades, controlled radical polymerization (CRP) has become very important, since it facilitates the synthesis of macromolecules of specific architectures with excellent control over the chemical and physical properties. Thus, this work presents the synthesis of new Mn(II) and Fe(II) complexes coordinated with the bidentate Schiff bases ligands, which are the result of the condensation of salicylaldehyde with cycloalkylamines: (1) cyclopentylamine, (2) cyclohexylamine, (3) cycloheptylamine and (4) cyclooctylamine, so that they can be used as mediators of radical polymerization mediated by organometallic (OMRP). The ligands synthesized were characterized by proton nuclear magnetic resonance (1H-NMR) spectroscopy, ultraviolet-visible (UV-Vis) absorption spectroscopy and Fourier-transform infrared spectroscopy (FTIR) techniques. The synthesized Mn(II) and Fe(II) complexes were studied by FTIR, UV-Vis, cyclic voltammetry (CV) and melting point (m.p.). Kinetic polymerization studies were performed for the manganese and iron complexes. The [MnIIbis (N-Salicylidene-Cyclopentylamine)], Mn(L1)2, complex showed a better control in the polymerization of vinyl acetate with lower values of polydispersity and the molecular mass curve (Mn) closer to the values of the theoretical curve. However, the iron mediator complexes presented a more similar behavior, not having much difference in the kinetic curves
Mestre
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Griessen, Christiane. "Contribution à l'étude de l'oxydation électrochimique du Mn(II) en Mn(III) en milieu sulfurique concentré : influences de Ag(I) comme catalyseur et de substances organiques en faible quantité /." Lausanne, 1985. http://library.epfl.ch/theses/?nr=576.
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Petitpierre, Jean-Philippe. "Contribution à l'étude de l'oxydation électrochimique du Mn (II) en milieu sulfurique; influence de l'argent (I) comme catalyseur /." Lausanne, 1989. http://library.epfl.ch/theses/?nr=775.
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Filsan, Ahmed Youssouf Filsane. "Etude des réponses optiques de nanocristaux à base de semiconducteurs II-VI : znTe, ZnS et de ZnS : mn." Thesis, Metz, 2011. http://www.theses.fr/2011METZ009S/document.
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Ce travail de thèse s’inscrit dans le cadre de l’étude des réponses optiques des nanocristaux à base de semiconducteurs II-VI. Ici nous avons déterminé les propriétés optiques de ZnTe, ZnS et ‘ZnS : Mn’ nanostructurés par ellipsométrie spectroscopique (SE). Nous avons déterminé la fonction diélectrique et les transitions optiques des NC-ZnTe par SE dans la gamme spectrale 0.6 à 6.5 eV. L’influence de la taille des NC sur les propriétés optiques et en particulier sur les transitions optiques a été aussi montrée. Les réponses optiques ont été déterminées en utilisant deux modèles : le modèle des points critiques d’Adachi et la loi de dispersion de Tauc-Lorentz. Tout au long de ce travail, nous avons tenté de contribuer à la compréhension du processus d’absorption dans les NC semi-conducteurs avec une technique non destructive capable de rendre compte des phénomènes liés à la réduction de la taille. Malgré le caractère indirect de l’ellipsométrie nécessitant une bonne connaissance de l’échantillon, nous avons démontré qu’elle est capable de déterminer plusieurs propriétés des NC (indice de réfraction complexe, coefficient d’absorption, énergie de gap, signatures des transitions optiques, excès de NC, taille moyenne, épaisseurs des couches de silice) et même de tenir compte des défauts liés à l’implantationIn this work, we report on the study of the optical responses of nanocrystals semiconductor based II-VI. Here we have determined the optical properties of nanostructured ZnTe, ZnS and 'ZnS:Mn' by spectroscopic ellipsometry (SE). We have obtained the dielectric function and optical transitions of NC-ZnTe by spectroscopic ellipsometry in the spectral range 0.6 à 6.5 eV. The influence of the NC size on the optical properties and on the optical transitions was also shown. The optical responses were extracted using two models: the generalized critical points model of Adachi and the Tauc-Lorentz dispersion formula. Throughout this work we have tried to contribute to the understanding of absorption processes in semiconductor NC with a nondestructive technique by tacking into account the phenomena related to quantum confinement. Despite the indirect nature of ellipsometry requiring a good knowledge of the sample, we demonstrated that it is able to determine several properties of NC (complex refractive index, absorption coefficient, energy gap, optical transition energies, NC of excess, thick layers of silica) and even to take account into defects due to implantation
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Bittencourt, Rodrigo Ferreira. "Síntese e avaliação de hidrogéis à base de alginato e nanopartículas magnéticas preparadas in situ para remoção de Mn(II) e Ni(II) de efluente industrial." Universidade do Estado do Rio de Janeiro, 2015. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=8935.
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Esta Dissertação teve como objetivo,a síntese de hidrogéis à base de alginato e nanopartículas magnéticas (maghemita) preparadas in situ. Os hidrogéis foram preparados em diferentes concentrações de alginato de sódio (2 e 3% m/v), FeSO4 (0,3 e 0,5 mol L-1) e CaCl2 (0,1 e 0,3 mol L-1). As propriedades físico-químicas dos hidrogéis foram analisadas e, posteriormente, foram avaliados quanto à capacidade de remoção de íons Ni2+ e Mn2+ de soluções aquosas. Para caracterização das amostras foram utilizadas diversas técnicas de análises, tais como, análise granulométrica, microscopia óptica (OM), microscopia eletrônica de varredura (SEM), microscopia eletrônica de transmissão (TEM), magnetometria de amostra vibrante (VSM), espectroscopia na região do infravermelho por transformada de Fourier (FTIR), difratometria de raios-X (XRD), espectroscopia Mössbauer, e análise termogravimétrica (TGA). Foram preparados hidrogéis com morfologia predominantemente esférica e dimensões micrométricas (500 a 850 m), com átomos de Fe e Ca dispersos uniformemente em sua estrutura. Os hidrogéis apresentaram boa resistência térmica e comportamento superparamagnético. As amostras foram intumescidas em água deionizada durante um intervalo de tempo a fim de avaliar o grau de intumescimento (Q) para determinar a amostra com a melhor resposta para posterior aplicação em solução aquosa contendo íons metálicos (Ni2+ e Mn2+). Os resultados revelaram que a amostra cuja concentração de 3% m/v de alginato de sódio, 0,3 mol L-1 de FeSO4 e 0,3 mol L-1 de CaCl2 obteve maior Q (50%). Em consequência deste resultado, optou-se por utilizar estaamostra, na remoção de metais pesados presentes em soluções aquosas e em efluentes industriais. Vários parâmetros,tais como: tempo de contato,pH, concentração inicial do íon e massa de hidrogel foram estudados.Os resultados, para efluente sintético, revelaram que o tempo de equilíbrio foi de 60 minutos; a capacidade de remoção dos metais melhora com o aumento de pH (3 a 9), sendo máxima em pH 7;quanto menor a concentração inicial da solução iônica (50 a 500 mg L-1), maior a capacidade de remoção, 52% de Ni2+ e 49% de Mn2+ (concentração inicial de 50 mg L-1). No efluente industrial, a remoção foi de 61% de Ni2+ e 57% de Mn2+(300 mg de hidrogel). Os resultados encontrados revelaram que os hidrogéis magnéticos produzidos à base de alginato têm potencial uso no tratamento de efluentes industriais contaminados com metais pesadosThis Dissertation aims thesynthesis of hydrogels based on alginate and magnetic nanoparticles (maghemite) prepared in situ. Hydrogels were prepared at different concentrations of sodium alginate (2 and 3% w/v), FeSO4 (0.3 and 0.5 mol L-1) and CaCl2 (0.1 and 0.3 mol L-1). The physicochemical properties of the hydrogels were analyzed and, subsequently, evaluated for their ability to remove ions Ni2+ and Mn2+ from aqueous solutions. In orderto characterize the samples,several techniques were used, such as, granulometric analysis, optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Mössbauer spectroscopy and thermogravimetry analysis (TGA). Hydrogels with predominant spherical morphology and micrometric dimension were prepared (500 and 850 m) with atoms of Fe and Ca dispersed uniformly in their structure. The hydrogels presented good thermal resistance and superparamagnetic behavior. The samples were swollen in deionized water, for a period of time, to evaluate the swelling degree (Q) and determine the sample with the best result for subsequent application in an aqueous solution containing metallic ions (Ni2+ and Mn2+). The results revealed that the sample with concentration of 3% w/v of sodium alginate, 0.3 mol L-1 of FeSO4, and 0.3 mol L-1 of CaCl2 presented the higher Q (50%). In consequence of this result, we decided to use thissample, in the removal of heavy metals from aqueous solution and industrial wastewater.Several parameters, such as: contact time, pH, initial concentration of ionic solution and hydrogel mass were studied. The results, to the synthetic solution, revealed that the equilibrium time was 60 minutes; the capacity of metals removal improves with the pH increasing (3 to 9), and was maximum at pH 7; the lower the initial concentration of ionic solution (50 to 500 mg L-1), the higher the removal capacity, 52% of Ni2+ and 49% of Mn2+ (initial concentration of 50 mg L-1). In the industrial wastewater, the removal was 61% of Ni2+ and 57% de Mn2+ (300 mg of hydrogel). The results showed that magnetic hydrogels based on alginate synthesized have potential use in the treatment of industrial wastewater contaminated with heavy metals
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Mathieu, Émilie. "Anti-oxidant Mn(II)-complexes : design and study in a cellular model of inflammatory diseases. Investigation of subcellular location." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066428.
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Les espèces réactives de l'oxygène (ROS) sont produites en continu dans tous les organismes aérobies et sont impliquées dans la signalisation cellulaire, les défenses contre les pathogènes, mais aussi le stress oxydant. Ce dernier correspond à un déséquilibre entre la production des ROS et leur prise en charge par les défenses anti-oxydantes de la cellule. Le stress oxydant est associé à de nombreuses pathologies, notamment les maladies inflammatoires chroniques de l'intestin (MICI). Parmi les métallo-enzymes qui contrôlent la concentration en ROS, les superoxide dismutases (SOD) jouent un rôle essentiel. Ces enzymes sont responsables de la régulation du superoxyde le premier ROS produit lors de la réduction du dioxygène. Dans ces travaux, des complexes de Mn(II) mimant l'activité de la Mn-SOD (SODm) ont été conçus en utilisant une approche biomimétique. Leur intérêt pour limiter le stress oxydant et l'inflammation dans un modèle cellulaire des MICI a été examiné. En particulier, leur activité biologique a été étudiée au vu de leurs propriétés physico-chimiques et de leur biodisponibilité. Les résultats obtenus avec un complexe parent ont mené à la conception d'une deuxième génération de SODm couplés à une sonde multimodale, à des peptides pénétrants, ou à des peptides adressant aux mitochondries. L'étude du complexe parent fonctionnalisé par des peptides polyarginines a démontré l'influence de charges positives portées par le ligand sur la constante de vitesse. Dans la continuité de l'approche biomimétique développée ici, la conception de SODm de novo est présentée et constitue un premier pas vers l'imitation de l'influence de la seconde sphère de coordinationReactive oxygen species (ROS) are produced continuously in all aerobic organisms and are involved in cell signaling, defenses against pathogens, but also oxidative stress. This latter corresponds to an imbalance between ROS production and their consumption by the antioxidant defenses of the cell. Oxidative stress is associated with numerous pathologies, such as inflammatory bowel diseases (IBD). Among the metalloenzymes controlling the concentration of ROS, superoxide dismutases (SOD) play a crucial role. These enzymes are responsibles for the regulation of superoxide, the first ROS produced by the reduction of oxygen. In this work, Mn(II) complexes mimicking the activity of the Mn-SOD (SODm) were designed using a biomimetic approach. Their relevance to limit oxidative stress and inflammation in a cellular model of IBD was investigated. In particular, their biological activity was studied in light of their physico-chemical properties and of their bioavailability. The results obtained with a parent complex led to the design of a second generation of SOD mimics conjugated with a single core multimodal probe, cell-penetrating peptides, or mitochondria-penetrating peptides. An effect of electrostatic interactions on the catalytic rate constant of the parent complex functionalized with polyarginines peptides was demonstrated, similarly to what is observed for the enzyme. In the continuity of the biomimetic approach envisioned here, the design of de novo SOD mimics is presented and constitutes a first step toward the mimicry of second sphere influence
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Santos, Jozemir Miranda dos. "Avaliação do efeito dos íons Cu(II), Fe(II), Fe(III), Ni(II) e Mn(II), na reação quimiluminescente do sistema peróxi-oxalato, visando o desenvolvimento de procedimentos analíticos para a determinação destes íons em óleos mineral e de oliva." reponame:Repositório Institucional da UFABC, 2010.
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Seifert, Steffen. "Synthese und Komplexbildungseigenschaften ausgewählter Maillard-Reaktionsprodukte." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1232923513056-87374.
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Zahlreiche Studien belegen, dass Maillard-Reaktionsprodukte (MRP) in vivo einen Einfluss auf den physiologischen Metallionenhaushalt haben können. Da bisher noch keine Korrelation zwischen dem Entstehen von definierten MRP und einem erhöhten Metallionenbindungsvermögen ermittelt werden konnte, war es das Ziel dieser Arbeit, die Komplexbildungseigenschaften der ausgewählten MRP Nε-Carboxymethyllysin, Isomaltol und Maltosin sowie deren Strukturanaloga Maltol, Deferipron, Mimosin und Pyridosin mit den physiologisch relevanten Metallionen Cu(II), Zn(II), Fe(III), Al(III) und Mn(II) zu untersuchen. Dazu wurden die MRP Nε-Carboxymethyllysin und Maltosin sowie die parallel untersuchten Substanzen Pyridosin, Maltosin-3-benzylether, Nα-Hippuryl- und Nα-Acetylmaltosin in ausreichender Menge und Reinheit synthetisiert. Dabei gelang es, für Maltosin und Pyridosin neue und effiziente Synthesewege zu entwickeln, bei welchen zum ersten Mal beide Substanzen gezielt aufgebaut wurden. Die Komplexbildungskonstanten der Liganden mit den Metallionen wurden pH-potentiometrisch bestimmt (I[KNO3] = 0,15 M; θ = 25 °C). Durch die Auswertung der Protonierungskonstanten der gebildeten Komplexe und das Vermessen geeigneter Derivate konnten für die untersuchten Komplexe zusätzlich die Koordinationsstellen der Liganden aufgeklärt werden. Die Untersuchungen zu den Komplexbildungseigenschaften bestätigten erstmals die Vermutung, dass MRP in der Lage sind, Metallionen zu binden. Dabei wurde weiterhin ermittelt, dass die Bindung von Cu(II) durch Nε-Carboxymethyllysin und von Fe(III), Al(III) und Cu(II) durch Maltosin durchaus von physiologischer Relevanz sind. Die Bedeutung der Ergebnisse wurde qualitativ durch Versuche mit Maltosin-derivatisiertem Rinderserumalbumin unterstrichen. Als besonderes Ergebnis der Arbeit ist herauszustellen, dass das MRP Maltosin und die Verbindung Pyridosin deutlich stabilere Komplexe mit Fe(III) bilden als das zur Fe(III)-Chelattherapie eingesetzte Medikament Deferipron. Diese festgestellte Eigenschaft bietet interessante Perspektiven für zukünftige Studien zur möglichen Anwendung von z. B. Maltosin als PharmakonSeveral studies show that Maillard reaction products (MRP) may influence the physiological metal ion balance. But none of these studies prove a correlation between the formation of defined MRP and an enhanced metal ion binding. Therefore it was the aim of this work to investigate the complex formation characteristics of the selected MRP Nε-carboxymethyllysine, isomaltol and maltosine as well as the structural analogues maltol, deferiprone, mimosine and pyridosine with the physiological relevant metal ions Cu(II), Zn(II), Fe(III), Al(III) and Mn(II). For that purpose the MRP Nε-carboxymethyllysine and maltosine plus the parallel analysed substances pyridosine, maltosine-3-benzylether, Nα-hippuryl- and Nα-acetylmaltosine were synthesised. Thereby new and efficient syntheses for maltosine and pyridosine were developed. The stability constants of the ligands with the metal ions were determined by pH-potentiometry (I(KNO3) = 0,15 M; θ = 25 °C). Furthermore the donor atoms within the formed complexes were determined by the evaluation of the protonation constants of the formed complexes and by the analysis of adequate derivatives. The studies to the complex formation characteristics confirm for the first time the assumption, that MRP are able to form stable complexes with metal ions. Withal it was ascertained that the coordination of Cu(II) by Nε-carboxymethyllysine and of Fe(III), Al(III) and Cu(II) by maltosine may be of physiological relevance. The significance of the results was pointed out by experiments with maltosine derivatised bovine serum albumine. The fact that the MRP maltosine and the compound pyridosine form more stable complexes with Fe(III) as the medicament for the Fe(III) chelate therapy deferiprone is a particular result of this work. This property affords interesting perspectives for future studies about a possible appliance of e.g. maltosine as pharmaceutical
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Franco, Carlos Ramon. "Troca ionica entre pectinatos de aluminio com diferentes graus de metilação, obtidos por hidrolise enzimatica, e os ions de Fe(III), Zn, Cu(II), Mn(II) e Ca em solução aquosa." [s.n.], 1996. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250368.
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Orientador: Aecio Pereira Chagas e Renato Atilio JorgeTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Alcover, Fortuny Gerard. "Spin-Crossover beyond the traditional Fe(II) complexes: ab initio study of spin-state stability in complexes with Mn, Ni and Ru." Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/396293.
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Tradicionalment el fenomen de spin-crossover s’ha estudiat en complexos hexacoordinats de Fe2+. L’objectiu d’aquesta tesi és aprofundir en aquest fenomen en complexos amb metalls de transició menys convencionals i altres nombres de coordinació mitjançant un estudi computacional.
El capítol 3 presenta l’estudi d’un compost de ruteni amb capacitat de transferir electrons a molècules acceptores i per tant amb potencials aplicacions en cel•les solars. En els capítols 4 i 5 s’analitzen complexos de Ni porfirina amb biestabilitat i spin-crossover per irradiació amb llum. El capítol 6 tracta dels estats magnètics i d’oxidació de complexos de manganès.
El treball estudia les diferències en la fotoquímica d’aquests metalls amb la dels complexos de ferro. L’exemple de la porfirina de Ni funcionalitzada amb un braç fenilazopiridínic dóna informació sobre el mecanisme de spin-crossover dirigit pel lligand amb canvi de coordinació. En els complexos de Mn, l’estabilitat relativa dels estats singlet i triplet depèn del caràcter sigma-donador del lligand axial.Tradicionalmente el fenómeno de spin-crossover se ha estudiado en complejos hexacoordinados de Fe2+. El objetivo de esta tesis es profundizar en este fenómeno en complejos con metales de transición menos convencionales i otros números de coordinación mediante un estudio computacional. El capítulo 3 presenta el estudio de un compuesto de rutenio con capacidad de transferir electrones a moléculas aceptoras y por lo tanto con potenciales aplicaciones en celdas solares. En los capítulos 4 y 5 se analizan complejos de Ni porfirina con spin-crossover después de ser irradiados por luz. El capítulo 6 trata de los estados magnéticos y de oxidación de complejos de manganeso. El trabajo estudia las diferencias en la fotoquímica de estos metales con la de los complejos de hierro. El ejemplo de la porfirina de Ni funcionalizada con un brazo fenilazopiridínico aporta información sobre el mecanismo de spin-crossover dirigido por el ligando con cambio de coordinación. En los complejos de Mn, la estabilidad relativa de los estados singlete y triplete depende del carácter sigma-dador del ligando axial.
Spin-crossover phenomenon has traditionally been studied for hexacoordinated Fe2+ complexes. The aim of this thesis is to get insight on this phenomenon in less conventional transition metals and other coordination numbers by means of a computational study. Chapter 3 presents the study of a ruthenium compound with ability to transfer electrons to acceptor molecules and, hence, with potential applications in solar cells. Chapters 4 and 5 analyze Ni porphyrin complexes exhibiting spin-crossover after irradiation with light. Chapter 6 treats the magnetic and oxidation states of manganese complexes. The work studies the differences in the photochemistry of these metals with respect to the iron complexes. The example of Ni porphyrin functionalized with a phenilazopyridine arm helps to understand the mechanism of coordination-induced spin-crossover. In Mn complexes, the relative stability of the singlet and triplet states depends on the sigma-donor character of the axial ligand.
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Seifert, Steffen. "Synthese und Komplexbildungseigenschaften ausgewählter Maillard-Reaktionsprodukte." Doctoral thesis, Technische Universität Dresden, 2008. https://tud.qucosa.de/id/qucosa%3A23758.
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Zahlreiche Studien belegen, dass Maillard-Reaktionsprodukte (MRP) in vivo einen Einfluss auf den physiologischen Metallionenhaushalt haben können. Da bisher noch keine Korrelation zwischen dem Entstehen von definierten MRP und einem erhöhten Metallionenbindungsvermögen ermittelt werden konnte, war es das Ziel dieser Arbeit, die Komplexbildungseigenschaften der ausgewählten MRP Nε-Carboxymethyllysin, Isomaltol und Maltosin sowie deren Strukturanaloga Maltol, Deferipron, Mimosin und Pyridosin mit den physiologisch relevanten Metallionen Cu(II), Zn(II), Fe(III), Al(III) und Mn(II) zu untersuchen. Dazu wurden die MRP Nε-Carboxymethyllysin und Maltosin sowie die parallel untersuchten Substanzen Pyridosin, Maltosin-3-benzylether, Nα-Hippuryl- und Nα-Acetylmaltosin in ausreichender Menge und Reinheit synthetisiert. Dabei gelang es, für Maltosin und Pyridosin neue und effiziente Synthesewege zu entwickeln, bei welchen zum ersten Mal beide Substanzen gezielt aufgebaut wurden. Die Komplexbildungskonstanten der Liganden mit den Metallionen wurden pH-potentiometrisch bestimmt (I[KNO3] = 0,15 M; θ = 25 °C). Durch die Auswertung der Protonierungskonstanten der gebildeten Komplexe und das Vermessen geeigneter Derivate konnten für die untersuchten Komplexe zusätzlich die Koordinationsstellen der Liganden aufgeklärt werden. Die Untersuchungen zu den Komplexbildungseigenschaften bestätigten erstmals die Vermutung, dass MRP in der Lage sind, Metallionen zu binden. Dabei wurde weiterhin ermittelt, dass die Bindung von Cu(II) durch Nε-Carboxymethyllysin und von Fe(III), Al(III) und Cu(II) durch Maltosin durchaus von physiologischer Relevanz sind. Die Bedeutung der Ergebnisse wurde qualitativ durch Versuche mit Maltosin-derivatisiertem Rinderserumalbumin unterstrichen. Als besonderes Ergebnis der Arbeit ist herauszustellen, dass das MRP Maltosin und die Verbindung Pyridosin deutlich stabilere Komplexe mit Fe(III) bilden als das zur Fe(III)-Chelattherapie eingesetzte Medikament Deferipron. Diese festgestellte Eigenschaft bietet interessante Perspektiven für zukünftige Studien zur möglichen Anwendung von z. B. Maltosin als Pharmakon.Several studies show that Maillard reaction products (MRP) may influence the physiological metal ion balance. But none of these studies prove a correlation between the formation of defined MRP and an enhanced metal ion binding. Therefore it was the aim of this work to investigate the complex formation characteristics of the selected MRP Nε-carboxymethyllysine, isomaltol and maltosine as well as the structural analogues maltol, deferiprone, mimosine and pyridosine with the physiological relevant metal ions Cu(II), Zn(II), Fe(III), Al(III) and Mn(II). For that purpose the MRP Nε-carboxymethyllysine and maltosine plus the parallel analysed substances pyridosine, maltosine-3-benzylether, Nα-hippuryl- and Nα-acetylmaltosine were synthesised. Thereby new and efficient syntheses for maltosine and pyridosine were developed. The stability constants of the ligands with the metal ions were determined by pH-potentiometry (I(KNO3) = 0,15 M; θ = 25 °C). Furthermore the donor atoms within the formed complexes were determined by the evaluation of the protonation constants of the formed complexes and by the analysis of adequate derivatives. The studies to the complex formation characteristics confirm for the first time the assumption, that MRP are able to form stable complexes with metal ions. Withal it was ascertained that the coordination of Cu(II) by Nε-carboxymethyllysine and of Fe(III), Al(III) and Cu(II) by maltosine may be of physiological relevance. The significance of the results was pointed out by experiments with maltosine derivatised bovine serum albumine. The fact that the MRP maltosine and the compound pyridosine form more stable complexes with Fe(III) as the medicament for the Fe(III) chelate therapy deferiprone is a particular result of this work. This property affords interesting perspectives for future studies about a possible appliance of e.g. maltosine as pharmaceutical.
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Queralt, Rosinach Núria. "Estudi de l'acoblament magnètic en complexos heterometàl·lics amb lligands pont oxamido, oxamato, tiooxalato i anàlegs." Doctoral thesis, Universitat Rovira i Virgili, 2010. http://hdl.handle.net/10803/9106.
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Aquest treball teòric estudia l'acoblament magnètic en complexos bi- i trinuclears heterometàl·lics amb lligands pont oxamido, oxamato, ditiooxalato i anàlegs. Per calcular la seva estructura electrònica s'han usat mètodes multireferencials, en particular diferents variants del mètode DDCI, desenvolupat en el grup, i el mètode CASPT2. Per diferents sistemes binuclears coneguts de Cu(II) i Mn(II), l'acoblament magnètic i els mapes de densitat de spin calculats reprodueixen acuradament les dades experimentals. L'acoblament antiferromagnètic en aquests depèn de la transferència de càrrega del lligand al metall, lligada a l'electronegativitat dels àtoms coordinats. En els sistemes hipotètics de tipus Cu(II)-M(II)-Cu(II), on M=Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu i Zn, la magnitud de l'acoblament estimada depèn de l'electronegativitat del metall central, anant de feblement ferromagnètic pel Sc a moderadament antiferromagnètic pel Cu. Aquest treball aporta la interpretació microscòpica de l'acoblament en aquests sistemes, així com la validació i/o les limitacions dels mètodes de càlcul emprats.This theoretical work examines the magnetic coupling in bi- and trinuclear heterometallic transition metal complexes with bridging ligands such as oxamido, oxamato, ditiooxalato and analogues. To calculate their electronic structure multireference methods have been used, including different variants of DDCI method, developed in our group, and CASPT2 method. For different Cu(II)-Mn(II) binuclear known systems, the magnetic couplings and spin density maps calculated accurately reproduce the experimental data. The antiferromagnetic coupling in these compounds depends on the charge transfer from ligand to metal, linked to the electronegativity of coordinated atoms. In the hypothetical systems of type Cu(II)-M(II)-Cu(II), where M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn, the magnitude of the estimated coupling depends on the electronegativity of the metal core, going from the weakly ferromagnetic for Sc to moderately antiferromagnetic for Cu. This work provides the microscopic interpretation of the coupling in these systems, as well as the validation and/or limitations of the computational methods used.
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Cavalcanti, Higo de Lima Bezerra. "Um estudo de estrutura eletrônica de algumas mn(ii/iii)-n-alquilpiridilporfirinas de alto spin: avaliação do efeito de crescente carga positiva ao redor do centro metálico." Universidade Federal da Paraíba, 2011. http://tede.biblioteca.ufpb.br:8080/handle/tede/7039.
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Synthetic manganese porphyrins comprise the most potent mimics of Superoxide Dismutases (SOD) and redox modulators in vivo. Superoxide (O2 ) and its reactive oxygen/nitrogen species progenies are associated to numerous human pathologies, such as stoke, cardiovascular conditions among others. The effectiveness of ortho Mn N-tetrapyridylporphyrin derivatives (MnT-2-PyP) as SOD mimics has been achieved by appropriate choice of the substituent on the pyridyl moieties to control lipophilicity, charge distribution, and electrostatic facilitation to O2 approach. Hereon we evaluate the semiempirical method PM6 on the treatment of manganese porphyrins based on a comparison over the structural features obtained theoretically and experimentally. Our evaluation on PM6 method showed us that it would not be an appropriate choice on the treatment of our interest complexes and then we decided to carry out a DFT level of theory treatment of MnXM-2-PyP (X = B, Tr, T), where each X indicates the sequencial methylation of the pyridyl groups, entailing an increase of positive charges. We investigate the effect of this increasing charge on some geometrical and electronic properties of aqua high-spin complexes. Geometry optimizations were performed with NWchem6.0 package, applying UDFT/B3LYP method (for a quintet or sextet spin state) with a 6-311G(d,p) basis set for all atoms except Mn where LANL2DZ ECP was used. Vibrational analysis was carried out, followed by an NBO analysis on the optimized structures with Gaussian 2009 package. For the Mn(II)P(H2O) systems studied, the NBO charge in the Mn atom increases with methylation and overall positive charge of the compound. The presence of a single water molecule as axial ligand drives Mn out of the porphyrin plan. An increase in positive charge is accompanied by an increase in Mn-N bond length, while Mn-O bond is shortened. We also point out the fact that the HOMO orbital of these complexes are primarily constituted of d orbitals basis functions from the metal center, and the addition of positive charges contribute to stabilize these orbitals. For the Mn(III)P(H2O)2 systems, the extra coordination water renders Mn nearly within the porphyrin plane. The HOMO orbital is now related to a double-occupied orbital while the LUMO orbital is given by about 55% of d orbitals and resembles the HOMO of Mn(II) species. These results may shed some light on the electronic and structural features underlying the catalytic activity of these compounds.
Porfirinas sintéticas de manganês compreendem os mais potentes mímicos da Superóxido Dismutase e moduladores redox in vivo. O Superóxido (O2 ) e suas espécies derivadas estão associados a numerosas patologias humanas, como derrame, doenças cardiovasculares, entre outras. A grande efetividade dos derivados da orto Mn N-tetrapiridilporfirina como mímicos de SOD tem sido atingida através da escolha apropriada do substituinte nas vizinhanças piridil de modo a controlar a lipofilicidade, distribuição de carga e facilitação eletrostática para a aproximação do O2 . Doravante avaliamos o método semi-empírico PM6 para o tratamento de porfirinas de manganês baseados numa comparação acerca de características estruturais obtidas teoricamente e experimentalmente. Nossa avaliação do método PM6 mostrou que este não seria uma escolha apropriada para o tratamento dos complexos de nosso interesse, então decidimos realizar uma abordagem em nível DFT das MnXM-2-PyP (X = B, Tr, T), onde cada X indica a seqüente metilação dos grupos piridil gerando um acréscimo das cargas positivas. Investigamos o efeito deste aumento de cargas em algumas propriedades geométricas e eletrônicas dos complexos aquosos de alto spin. Otimizações de geometria foram realizadas com o pacote NWchem6.0, aplicando o método UDFT/B3LYP (para estados quinteto ou sexteto) com um conjunto de base 6-311G(d,p) para todos os átomos exceto Mn, onde o ECP LANL2DZ foi usado. Desempenhamos uma análise vibracional seguida de análise das cargas NBO no pacote Gaussian09. Para os sistemas Mn(II)P(H2O) estudados, a carga NBO no átomo de Mn cresce com a metilação. A presença de uma única molécula de água como ligante axial leva o Mn para fora do plano da porfirina. O aumento na carga positiva é acompanhado por um aumento na distância Mn-N, enquanto a distância Mn-O é encurtada. Apontamos o fato de que o orbital HOMO destes complexos são primariamente constituídos de funções de base dos orbitais d do centro metálico, e a adição de cargas positivas contribui para estabilizar este orbital. Para os sistemas Mn(III)P(H2O)2, a água de coordenação extra torna o Mn aproximadamente planar com relação ao plano da porfirina. O orbital HOMO é agora relacionado a um orbital duplamente ocupado, enquanto o LUMO é dado por cerca de 55% de orbitais d e assemelha-se ao HOMO das espécies Mn(II). Estes resultados podem trazer esclarecimentos sobre características relacionadas à atividade catalítica destes compostos.
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Merdy, Patricia. "Etude de la complexation et de la sorption des cations Mn(II), Cu(II) et Fe(III° par une lignine et différents modèles moléculaires : influence de la teneur en ions calcium et carbonate présents dans les sols de craie." Reims, 2001. http://www.theses.fr/2001REIMS025.
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Le rôle des cations métalliques dans les processus de biodégradation de la lignine est peu connu. Ces cations sont certainement impliqués, en complément à l'action des enzymes et des microorganismes, dans des réactions radicalaires dégradatives. De plus, le transport des ions dépend de la présence de lignine qui va déterminer en partie leur concentration et leur spéciation dans les sols. Dans ce contexte, nous nous sommes attachés à l'étude des interactions entre une lignine de paille de blé et les cations métalliques Cu(II), Fe(III) et Mn(II), très abondants dans les sols. Afin de comprendre les phénomènes se produisant spécifiquement dans les sols de craie, caractéristiques de la région Champagne-Ardenne, l'influence de la teneur en ions calcium et carbonate sur la complexation des métaux de transition par la lignine, a également été étudiée. Dans un premier temps, étant donné la complexité structurale de la lignine, l'étude a été réalisée sur des molécules modèles simples, représentatives des motifs structuraux trouvés dans la lignine native : trois acides cinnamiques (précurseurs de la lignine), l'alcool coniférylique et un dimère. Cette étude a été menée en solution aqueuse afin de rendre compte des phénomènes de complexation en solution se produisant dans les sols avec des fractions solubles de lignine. Dans un second temps, trois modèles polymériques ont été étudiés : un déhydropolymère (lignine de synthèse) et deux substrats extraits de la paille de blé. De nombreuses techniques physico-chimiques (RMN du solide, potentiométrie, XPS, etc) ont été mises en œuvre pour caractériser préalablement ces trois solides.
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Zue, Mve Mexent [Verfasser]. "Préparation et caractérisation des charbons actifs obtenus à partir des coques de noix de Coula edulis : Application dans l’élimination en solution aqueuse des cations Mn (II) et Al (III) et des substances humiques / Mexent Zue Mve." München : GRIN Verlag, 2018. http://d-nb.info/1159960410/34.
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Saarnio, J. (Juha). "Distribution of carbonic anhydrase IX, MN/CA IX, in normal and neoplastic gastrointestinal and hepatobiliary tissues:its potential value as a new biomarker and comparison of its expression with that of isoenzymes I, II, IV, V, and VI." Doctoral thesis, University of Oulu, 2000. http://urn.fi/urn:isbn:9514257901.
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Abstract
The carbonic anhydrase (CA) gene family contains eleven active members, the basic physiological functions of which are linked to the interconversion of carbon dioxide and bicarbonate (CO2 + H2O ⇔ H+ + HCO3⇔ H2CO3-). They participate in a variety of physiological processes that involve pH regulation, CO2 and HCO3- transport and water and electrolyte balance, and some new functions have also been suggested recently. A novel tumour-associated antigen, MN, containing a CA-domain and named MN/CA IX, has been found to promote cell proliferation when transfected into NIH3T3 cells and has also been shown to be a potential biomarker for neoplasia in the uterine cervix.
The present study examines the expression of MN/CA IX in the normal alimentary tract by immunohistochemistry and compares it with the expression of cytoplasmic CA I, CA II, apical plasma membrane associated CA IV and secretory CA VI. The distribution of mitochondrial CA V is examined by immunohistochemistry and Western blotting. The value of MN/CA IX as a potential biomarker of gastrointestinal tumours is assessed in a series of colorectal and hepatobiliary neoplasms.
A positive immunoreaction for MN/CA IX was detected in the basolateral plasma membrane of the gastric, intestinal and biliary epithelium, but was confined to the proliferating cryptal enterocytes in the human gut, suggesting a role in cellular proliferation. In colorectal tumours, MN/CA IX immunoreaction was also located in the proliferative zone, indicating that it could be a useful marker of cellular proliferation. In the case of hepatobiliary tumours a positive signal was mainly associated with tumours of biliary epithelial parentage.
These results demonstrate that MN/CA IX has a unique expression pattern in the alimentary tract relative to other CAs. Its localization and enzymatic properties suggest that it may have a dual function in the gastrointestinal epithelium. Through its CA activity it could participate in the regulation of carbon dioxide/bicarbonate homeostasis, while its localization to the basolateral surfaces of proliferating cryptal enterocytes suggests that it may serve as a ligand or receptor for one or more other proteins that regulate intercellular communication and/or cell proliferation. MN/CA IX may also serve as a new biomarker of gastrointestinal tumours.
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Hartmann, Jean-Michel. "Epitaxie par jets moléculaires alternés d'hétérostructures CdTe/Mn(Mg)Te : application à la réalisation de super-réseaux verticaux." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10204.
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Le but de ce travail est de developper des methodes de croissance pour fabriquer in-situ des nanostructures - en particulier des reseaux de fils quantiques - a base de semiconducteurs ii-vi de la famille des tellurures. Pour ce faire, nous avons fait appel a l'epitaxie par jets moleculaires alternes (envoi alterne des elements ii et des elements vi), technique permet un controle ultime des phenomenes d'incorporation des atomes en surface. Nous avons obtenu pour cdte deux regimes d'autoregulation, le premier a 0. 5 monocouches (mc) de cdte deposees par cycle d'ejma entre 260c et 290c, le second a 1 mc/cycle entre 230c et 240c. Pour mgte, un regime d'autoregulation a 0. 7mc/cycle d'ejma a ete mis en evidence entre 260c et 300c. Pour mnte, par contre, tous les atomes de mn incidents s'incorporent a 280c. Une etude systematique de super-reseaux cdte/mnte et cdte/mgte nous a permis d'une part d'evaluer et d'optimiser la morphologie des interfaces, d'autre part d'avoir acces a des parametres physiques importants de mgte (parametre de maille 6. 42 a, energie de bande interdite a l'ambiante 3. 5 ev, rapport des constantes elastiques 2c#1#2/#c#1#1=1. 06) comme de mnte (2c#1#2/#c#1#1=1. 12). En particulier, un modele de segregation a ete utilise pour decrire quantitativement les interfaces directes et inverses des super-reseaux cdte/mnte. Enfin, nous avons obtenu en croissance par avancees de marches sur surfaces vicinales des super-reseaux inclines (sri) cdte/mnte. Une grande regularite de la periode et de l'angle d'inclinaison de ces sri a ete demontree, avec une modulation laterale de la composition en mn de l'ordre de10%. Ce potentiel lateral de confinement a ete mis en evidence en optique a l'aide de mesures d'anisotropie de la polarisation.
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Marsal, Laurent. "Elaboration et caractérisation de nanostructures auto-organisées de semiconducteurs II-VI." Université Joseph Fourier (Grenoble), 2001. http://www.theses.fr/2001GRE10037.
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Nous presentons dans ce travail la mise au point des conditions de croissance epitaxiale permettant d'elaborer de maniere auto-organisee des nanostructures 1d et 0d a base de semiconducteurs ii-vi de la famille des tellurures. Les boites quantiques sont realisees en epitaxie par jets atomiques dans le systeme cdte/znte (desaccord de maille de 6,2%), et nous montrons que dans ce cas la croissance n'est pas de type stranski-krastanow. Ce sont des poches riches cd dans une matrice de znte qui sont responsables du comportement 0d. En particulier, l'emission excitonique d'une boite unique a pu etre observee. Les fils quantiques (cdte/cdmn (mg)te) sont realises en epitaxie par jets moleculaires sur des substrats vicinaux permettant de travailler en regime d'avancee de bords de marches : nous obtenons ainsi un superreseau de fils, dont l'inclinaison est determinante dans le caractere 1d du systeme. Un calcul complet de la structure de bandes est confronte aux resultat experimentaux. Une etude de spectroscopie optique sur l'ensemble de ces nanostructures est presentee. En particulier les experiences de temps de declin de la luminescence sont caracteristiques du type de systeme etudie : le comportement du temps de declin avec la temperature est la signature de la dimensionnalite de nos systemes.
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AGUSTIN, DOMINIQUE. "Bases de schiff et coordinences non usuelles du germanium, de l'etain et du plomb : (base de schiff)m(ii), (base de schiff)m = x et (base de schiff)m n = ml m (m = ge, sn, pb ; x = s, se, n-sime 3 ; m = w, cr, fe et mn ; n = 1, 2)." Toulouse 3, 1999. http://www.theses.fr/1999TOU30162.
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Ce travail concerne l'etude d'especes organometalliques stables des types >m, >m = y (y = o, s, se, n-sime 3) et (>m) nm (m : metal de transition) a metal 14 a coordinence non usuelle. Le premier chapitre est une mise au point bibliographique concernant les basses coordinences stables des types > m et (> m) nm (m = ge, sn, pb). Le deuxieme chapitre concerne la synthese et l'etude physicochimique des nouvelles especes divalentes l 2m (m = ge, sn, pb ; l 2 = base de schiff). Les donnees spectroscopiques soulignent la coordination intramoleculaire n-m-n. Des reactions de cycloaddition et la structure rx de l'adduit (salen)sn-3,5-di-tert-butyl-1,2-benzoquinone sont presentes. Des insertions d'aldehydes ou de clivage par des acides organiques et des chlorures d'acides conduisent, a partir de (salen)m, a de nouveaux composes divalents heteroleptiques. Le troisieme chapitre concerne les complexes (salen)m nm(co) 6 - n (m = ge, sn, pb ; m = cr, w, n = 1, 2) 2. Les structures rx indiquent le caractere double de la liaison sn = m. Les complexes (salen)m = m(co) 5 (m = ge, sn ; m = cr, w) conduisent, par des reactions de cycloaddition et de substitution de ligands, a de nouvelles especes a enchainement p-w-sn ou a des composes trimetalles sn-m-sn (m = cr, w). Le quatrieme chapitre decrit les complexes (salen)m = mncp(co) 2 (m = ge, sn, pb), (salen)sn = fe(co) 4 et leurs structures rx. Le caractere double de la liaison (salen)m-ml n, du au caractere -donneur et au fort caractere -accepteur de (salen)m, est demontre par l'obtention de la plus courte liaison sn-mn connue dans (salen)sn = mn(cp)(co) 2. La position axiale de (salen)sn dans la structure de (salen)sn = fe(co) 4 demontre que (salen)sn est plus -donneur que -accepteur vis-a-vis du fer. Le cinquieme chapitre traite de la reactivite des especes divalentes (salen)m vis-a-vis d'oxydants conduisant a de nouvelles especes insaturees de type (salen)m = y (m = ge, sn ; y = s, se, n-sime 3) ; certains aspects de leur reactivite sont egalement presentes. La derniere partie concerne des transferts de ligands entre (salen)sn et des composes halogenes (bf 3. Me 2o, cp 2ticl 2, nicl 2. Dppe, pcl 3, tbupcl 2, cl 3p = x (x = o, s)) conduisant a de nouveaux composes lineaires ou cycliques a ligand salen du bore, du titane, du nickel et du phosphore (neutres ou cationiques).
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Luttmann, Michel. "Ellipsométrie spectroscopique à angle variable : applications à l'étude des propriétés optiques de semi-conducteurs II-VI et à la caractérisation de couches à gradient d'indice." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10232.
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Ce travail apporte une contribution a la caracterisation des couches minces par ellipsomerie spectroscopique a angle variable. Nous presentons les differentes modifications apportees a l'ellipsometre d'origine et decrivons les procedures d'etalonnage utilisees. La reduction des erreurs systematiques et aleatoires est egalement traitee. Une etude originale a ete menee sur les derivees partielles des angles ellipsometriques psi et delta par rapport aux differents parametres de l'echantillon (epaisseurs, indices, angle d'incidence). Celle-ci nous a conduit a introduire le concept de sensibilite integrale relative (sir) qui s'est avere tres utile pour localiser les zones angulaires les plus interessantes et pour comparer entre elles les sensibilites de la mesure ellipsometrique aux divers parametres de l'echantillon. L'interet de mesures spectroscopiques a plusieurs angles d'incidence est discute. Deux applications principales ont ete traitees dans ce memoire: la premiere concerne la mesure des indices de semi-conducteurs ii-vi a grands gaps. L'etude realisee porte sur des substrats massifs de cdmnte et sur des couches epitaxiees de cdmgte. Une loi d'indice permettant de decrire le comportement de la fonction dielectrique du cdmgte sur l'ensemble du domaine spectral est proposee. Dans la zone transparente, deux lois de sellmeier donnant les indices du cdmnte et du cdmgte pour toute concentration de manganese ou de magnesium, ont ete etablies. La seconde porte sur la caracterisation de couches a gradient d'indice. Une methode permettant d'analyser des couches de profil d'indice a priori quelconque est proposee. Elle a ete validee sur des couches inhomogenes de gaalas et d'oxy-nitrure de silicium. L'ellipsometrie s'est revelee etre une technique bien adaptee a ce type de caracterisation puisque des profils polynomiaux du quatrieme degre ont pu etre mis en evidence sur des couches d'oxy-nitrure de silicium a fort gradient d'indice
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Ferrand, David. "Interactions d'échange ferromagnétiques induites par un gaz de trous dans des hétérostructures 2D et des couches 3D de semi-conducteurs II-VI." Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10174.
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L'electronique de spin se propose de realiser de nouveaux dispositifs bases sur le controle a la fois du spin et de la charge des porteurs. Dans ce cadre, les semiconducteurs magnetiques dilues ii-vi (cd ( 1 - x )mn xte et zn ( 1 - x )mn xte) constituent des materiaux modeles pour les etudes fondamentales avec des systemes physiques originaux comportant des spins localises couples par des interactions d'echange avec un gaz de porteurs de dimensionalite variable (3d, 2d), et avec une densite que l'on peut faire varier independamment de la concentration de spins. Ce travail est consacre a l'etude de deux types de structures, des couches epaisses 3d de zn ( 1 - x )mn xte degenerees de type p, et des heterostructures 2d constituees de puits quantiques cd ( 1 - x )mn xte dopes p par modulation de dopage. On observe dans ces deux types d'echantillons des interactions d'echange ferromagnetiques induites par le gaz de trous (temperature de curie-weiss positive), et la presence d'une phase magnetique ordonnee en dessous de la temperature de curie-weiss. Les temperatures de curie-weiss observees sont en bon accord avec la description du couplage entre les spins et le gaz de trous dans un modele de champ moyen les couches de zn ( 1 - x )mn xte ont ete caracterisees avec des mesures de transport sous champ magnetiques entre 1. 5k et 300k et des mesures d'aimantation. Les mesures de transport montrent la presence d'effets de localisation importants en dessous de 15k avec la formation de polarons magnetiques et la presence d'effet hall anormal resultant de l'effet important du couplage spin-orbite sur les trous. Les proprietes magnetiques des puits quantiques sont determinees par spectroscopie magnetooptique en champ faible. Nous avons caracterise les proprietes electroniques du gaz de trous 2d avec des mesures de transport entre 300k et 15k et par des mesures de spectroscopie magnetooptique en champ fort (0-20t) qui mettent en evidence un role important des effets excitoniques (excitons, excitons charges x+).
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Ourari, Ali. "Étude de deux réactions d'électrocatalyse : hydrogénation électrocatalytique sur des films de polymères contenant des microparticules de métaux nobles et activation de l'oxygène par des complexes Mn(III) - bases de Schiff." Université Joseph Fourier (Grenoble ; 1971-2015), 1995. http://www.theses.fr/1995GRE10171.
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Ce travail est relatif a l'etude de deux reactions d'electrocatalyse. La premiere partie concerne la mise au point de cathodes moleculaires, realisees par l'inclusion de microparticules de metaux nobles dans des films de polypyrrole fonctionnalise et a leur application en hydrogenation electrocatalytique. L'etude de l'hydrogenation de deux substrats test, le limonene et la carvone, a montre qu'il est possible d'orienter la selectivite de ces electrodes modifiees selon la nature du metal incorpore (pt, pd ou rh). Le resultat le plus significatif est que l'incorporation dans le meme film de polymere de deux metaux d'activite catalytique differente (pt + pd ou rh + pd) conduit a des cathodes dont l'efficacite et la selectivite sont largement superieures a celle des cathodes basees sur un seul metal. La deuxieme partie de ce travail est consacree a l'etude de l'activation electrochimique de l'oxygene par des complexes mn (iii) - bases de schiff. Il apparait que le complexe mn (ii) - salen substitue en 5,5 par des atomes de chlore est le catalyseur le plus stable et le plus efficace pour la reaction test d'epoxydation du cyclooctene. D'autre part, la rigidification du complexe par l'utilisation d'un pont 1,2-cyclohexylidene ou 1,2-phenylene reliant les deux motifs salicylaldehyde du ligand, a la place du groupe ethylidene ligand salen, entraine une forte diminution de l'activite catalytique des complexes correspondants. Ce systeme electrocatalytique a egalement ete applique a l'oxydation de la tetraline et de la triphenylphosphine
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Klewicki, J. Kenneth. "The Kinetics of Redox Reactions of Mn(II) and Mn(III) in Aqueous Systems: Homogenous Autoxidation of Mn(II) and the Formation and Disappearance of Mn(III) Complexes." Thesis, 1996. https://thesis.library.caltech.edu/5074/9/Klewicki_jk_1996.pdf.
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The kinetics of manganese redox reactions are important for understanding redox cycles in natural waters. This study examined the kinetics of the homogenous oxidation of Mn(II) and formation and disappearance of Mn(III) complexes.
The oxidation of Mn(II) was studied to determine the homogenous oxidation rate in the absence of solid surfaces and biological activity. Experiments were conducted at 35, 45, 50, and 60°C. The pH was 8.0. The reaction solution was prepared so that at no time during the experiment was the solubility product of any solid phase exceeded. Oxidized Mn was measured using leuco crystal violet dye reagent. Measurable rates were observed for the 45, 50, and 60°C experiments. An Arrhenius expression was fitted to the rates in order to extrapolate to 25°C. The second order rate constant for the rate expression
-d[Mn(II)]/dt = k⋅[Mn(II)⋅[O2]
was calculated to be 6.9 ± 1.6 x 10-7 M-1s-1.
The kinetics of disappearance of Mn(III) complexes from aqueous solution were studied. Complexes of pyrophosphate (P2O74-), ethylenediaminetetracetate (EDTA), and citrate (CIT) were synthesized from MnO4- and a Mn(II) salt in a 1:4 ratio in the presence of excess ligand. Concentrations of Mn(III) complex were monitored spectrophotometrically. Experiments were conducted in the pH range of 6 to 9 for pyrophosphate and citrate and 3 to 9 for EDTA. The total manganese concentration was varied between 0.5 and 1.0 mM. Ligand concentrations were varied from 0.5mM to 200mM. Experiments were also conducted to examine the effects of oxygen, light, and ionic strength. Oxygen had a significant effect on only the citrate complex; ionic strength affected only the EDTA complex. Light was found to be insignificant in all cases.
The Mn(III)P2O7 complex was found to disappear from solution relatively slowly providing the ligand was in at least ten-fold excess. Disappearance time scales were on the order of 107 s. The Mn(III)EDTA complex reacted rather rapidly with time scales on the order of 104 s. There were at least two Mn(III)EDTA complexes, a protonated one more stable at low pH and an unprotonated one more stable at high pH. The pKa of the complex appeared to be approximately 5.3. The rate of disappearance of the Mn(III)EDTA had a fractional dependence on pH, probably indicative of an unknown pH dependent intermediate in the decomposition of the complex. The rate was found to increase with increased EDTA, indicating that the rate limiting step was an outer sphere electron transfer from Mn(III)EDTA to an excess EDTA. The rate law for the reaction above pH 6 was found to be
-d[Mn(III)EDTA]/dt = k⋅[H+]0.31⋅[EDTA]1.35⋅[Mn(III)EDTA]
The Mn(III)CIT complex was found to undergo a redox cycle. The Mn(III)CIT complex was reduced, forming Mn(II). The Mn(II) was then oxidized in the presence of oxygen to re-form the Mn(III) complex. Both pH and ligand concentration were found to have fractional orders in the rate expression, largely due to the competition between the reduction and the oxidation and possibly complicated by radicals formed by the reaction.
The dissolution of MnOOH by pyrophosphate, EDTA, and citrate was studied. A MnOOH solid was synthesized by oxidizing Mn(II) with hydrogen peroxide at elevated temperatures and high pH. The solid was identified by X-ray diffraction to be β-MnOOH, with some contamination by Mn3O4. Throughout the dissolution process samples were removed by pipette and filtered. The filtrate was analyzed spectrophotometrically for the presence of Mn(III) complexes and total Mn. The solids captured on the filter were analyzed by an iodine titration technique, coupled with formaldoxime measurements to determine the average oxidation state of the solids. The effects of pH and ligand concentration on rates were examined.
Pyrophosphate was found to dissolve the Mn(III) solids nonreductively, producing the Mn(III) complex in solution. The dissolution reaction rate was dependent on approximately the half power of [H+], possibly indicative of a surface binding ligand binding on the surface. No dependence on the ligand concentration was found down to a ligand:Mn ratio of 10:1, probably indicative of surface site saturation by ligand.
EDTA was found to dissolve the solids reductively with no Mn(III) solution species being observed. The dependence on [H+] was approximately one half order, possibly indicative of a surface binding.
Citrate dissolved the MnOOH solids in what appeared to be two steps. There seemed to be an initial stage of nonreductive dissolution, followed by a reductive dissolution. The rate and duration of the two different stages depended on pH. The dependence was slightly greater than first order in [H+], possibly indicating the reaction becomes controlled by reactions of the radicals produced by oxidation of the citrate.
This study has shown that Mn(III) complexes can be formed in pH conditions relevant to natural waters. These complexes can be formed either through oxidation of Mn(II) by strong oxidants in the presence of stabilizing ligands or by dissolution of Mn(III)-containing solids by stabilizing ligands. Once formed, the lifetime of these complexes will depend on the nature of the ligand and chemical characteristics of the aquatic environment. If the ligand does not rapidly reduce Mn(III) these complexes can be powerful mobile oxidants which could significantly affect the local redox environment.
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LIN, SHENG-LUNG, and 林昇龍. "Vanadate-Co(II), Ni(II), Mn(II) and Cu(II) Coordination Polymers:Synthesis, Structures and Magnetic Characterization." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/39616697490916852975.
Full textAbstract:
碩士東海大學
化學系
104
This work reports on the synthesis, structures and properties of five vanadate-based coordination polymers with Mn(II), Ni(II), Co(II) and Cu(II) ions. The reactions of NH4VO3 with Co(NO3)2·6H2O and Ni(NO3)2·6H2O in water at 80 ℃ produce [Co(VO3)2(H2O)2]n (1) and [Ni(VO3)2(H2O)2]n (2) respectively. Compound 1 and 2 are isostructure. The structure of compounds 1 and 2 cotains a one dimensional zigzag chain of coner-shared VO4 tetrahedron, which further connects the metal ions to three dimensional framework. Compound 3 was synthesized by the hydrothermal reaction of NH4VO3 with Cu(NO3)2 ·3H2O at 180 ℃. The structure of compound 3 adopts a three dimensional structure, which comprise a two dimensional Cu(II) layer by the linked of (V2O7) unit. The reaction of NH4VO3 with Co(NO3)2·6H2O (4) and Mn(NO3)2·4H2O (5) are obtained. In the compounds 4 and 5, the metal ions are bridged by ladder-like chain of edge-shared (VO4) units. Magnetic measurements of compounds 1 – 5 reveal that the metal ions are antiferromagnetic coupled in compounds 1, 3, 4 and 5, but ferromagnetic coupled in compound 2. Indeed, compound 4 shows metamagnetic transition from antiferromagnetic state to paramagnetic state with HC = 9000 Oe.