Orientador: Carlos Frederico de Oliveira Graeff / Banca: Marcelo Mulato / Banca: José Humberto Dias da Silva / Banca: Carlos José Leopoldo Constantino / Banca: Alvaro Antonio Alencar de Queiroz / O programa de Pós graduação em Ciência e Tecnologia de Materiais, PosMat, tem carater institucional e integra as atividades de pesquisa em materiais de diversos campi da UNESP / Resumo: O óxido nítrico (NO) é um radical livre conhecido por desempenhar importantes funções fisiológicas, sendo associado, entre outros processos, ao fator de relaxamento da musculatura lisa vascular, importante para a regulagem da pressão sanguínea. Para a determinação dos mecanismos através do qual o NO influencia e controla os processos fisiológicos, é de fundamental importância o desenvolvimento de sensores que possibilitem a sua determinação quantitativa. Neste trabalho, foram obtidos e caracterizados sensores sólidos para NO através de duas maneiras: 1 - Enquadramento do complexo ferro(II)-dietilditiocarbamato (FeDETC) na matriz híbrida de siloxano-poli(oxipropileno) (PPO) utilizando um método sol-gel modificado. 2 - Formação de um complexo de inclusão do FeDETC com cucurbit[n]urilas. A detecção de N0, nesses sensores, se dá através de Espectroscopia de Ressonância Paramagnética Eletrônica, baseada na formação de um complexo paramagnético estável ferro(II)-DETC-NO, o qual exibe três linhas características no espectro de RPE(gef=2,04). Os sendores apresentaram bom desempenho. O sensor baseado em PPO, apresentou sensibilidade de 2,5x108 μM-1, com faixa de trabalho entre 100 nM e 1 mM. O sensor CB[6]FeDETC apresentou o limite de detecção de 2,9 nM, limite de quantificação de 16 nM. A faixa de trabalho desse sensor é de 1,37x1015 spings/g a 1x1019 spins/g. Esses resultados são comparáveis aos melhores sensores divulgados na literatura / Abstract: The nitrogen monoxide (NO) is a free radical known to play important physiological roles, being associated with, among other processes, the relaxation factor of vascular smooth muscles, important for the regulation of blood pressure. To determine the mechanisms by which NO influences and controls the physiological processess is of fundamental importance the development of sensors that allow quantitative determination of NO. In this work, solid-state sensors for NO were obtained by two ways: 1 - Encapsulation of the complex iron (II)-diethyldithiocarbamate (FeDETC) in the hybrid matrix of siloxane-poly (oxipropilene) (PPO) using a modified sol-gel method. 2 - Formation of an inclusion complex with the FeDETC cucurbit[n]uril. The detection of NO in these sensors, is performed by Electron Paramagnetic Resonance Spectroscopy, based on the formation of a stable paramagnetic complex iron[II]-DETC-NO, which displays three eharacteristic lines in the EPR spectrum (gef=2,04). The sensors showed good performeance. The PPO based sensor showed a sensitivity of 2.5x108 μM-1, a working range between 100 nM and 1 mM. The sensor CB[6]/FeDETC showed the detection limit of 2.9 nM, quantification limit of 16 nM. The working range of this sensor is between 1.37x1015 spins/g and 1x1019 spins/g. These results are comparable to the best sensors reported in the literature / Doutor

A new Ph.D research project was started early October into the Department of Civil, Environmental and Natural Resources Engineering at Luleå University of Technology (LTU) by Sarah CONRAD under the direction of Johan INGRI. The part of this project in which I participed was the determination of the concentration of Fe (II) by flow injection analysis using chemiluminescence in the Bothnia Bay. The missions were to handle the instrument and the software and to prepare also some sample standards for the calibration of the FIA. The stream water is first sampled and filtered. Then the water, containing either just the natural iron in the water or after addition of artificial iron, is analyzed by flow injection analysis in combination with luminol. The results are saved on the laptop and interpreted later. The experiments were performed on both the field and the laboratory of the University. / <p>Validerat; 20131008 (global_studentproject_submitter)</p>

Cette thèse décrit le développement et de la caractérisation de sondes moléculaires répondant à des analytes chimiques en solution par le passage d’un état diamagnétique à un état paramagnétique (mode off-on).Dans le but de concevoir de tels outils, nous avons focalisé notre attention sur les chélates de fer(II) avec des ligands de type bispidine bicyclique puisqu’ils présentent, entre autres, une stabilité suffisante même en milieux compétitifs comme l’eau. Ce manuscrit décrit des protocoles synthétiques robustes pour leurs préparations à grande échelle. Les complexes synthétisés ont été entièrement caractérisé en solution (RMN 1D/2D, MS, UV-Vis, CV) et dans l’état solide (rayon X et SQUID). Je suis notamment parvenu à synthétiser le premier exemple de complexe bispidine-fer(II) diamagnétique, bas spin, ainsi qu’à proposer des paires de chélates diamagnétique-paramagnétique aux structures connexes. Nous avons donc à notre disposition un système magnétique off-on valide, qui permet le design de sondes répondant à un stimulus (bio)-chimiques (biomarqueurs enzymatiques par ex.) par fonctionnalisation d’un synthon clé en une seule étape. Les deux premières sondes de ce type sont décrites ici, une répondant à la présence d’anions particuliers et l’autre répondant au pH.Au cours de ce travail, nous avons également mis au point la préparation du tout premier complexe de fer(II) radioactif avec un ligand insoluble en milieu aqueux et nous l’avons utilisé pour faire une étude préliminaire de biodistribution chez la souris. Ce protocole original pourrait être adapté pour virtuellement toute sonde à base de complexes de fer(II). Les données de relaxivité obtenues pour les modes silencieux et actif en IRM en conjonction avec le comportement in vivo de la forme active chez la souris semblent être prometteuses quant à la création d’une sonde IRM fonctionnant sur le principe du mode off-on.Les méthodologies et designs moléculaires présentés ici ouvrent le champ au développement de sondes moléculaires magnétogéniques opérationnelles en solution, qui n’avait, pour l’heure, jamais été synthétisé. L’avènement de tels outils présente de nombreuses perspectives pour des applications dans les domaines technologiques, environnementales et biomédicales. / This work concerns the development and characterization of molecular probes that respond to a chemical analyte in a liquid sample by turning from a diamagnetic to a paramagnetic state (off-on mode).With the aim of designing these tools, we focused on iron(II) chelates of bicyclic bispidines as they promised, among others, sufficient probe stability, even in competitive media like water. This manuscript describes new robust synthetic protocols for their large-scale preparation. Synthesized bispidine-iron(II) complexes were thoroughly characterized in solution (1D/2D NMR, MS, UV-Vis, CV) and in the solid state (X-ray and SQUID). In particular, I report here the first diamagnetic, low spin examples thereof, as well as pairs of structurally related diamagnetic-paramagnetic chelates. It now enables the design of responsive probes for various (bio)-chemical targets (including enzyme biomarkers), accessible by one-step functionalization of a key synthetic intermediate with suitable trigger moieties. The first two such probes are described herein, which respond to the presence of a particular kind of anion or a change in the pH.In addition in the course of my work, the unprecedented radioactive iron(II) (Fe-59 isotope) complex of a model water-insoluble ligand was prepared and used in an initial biodistribution study in mice. This original protocol can now be directly adapted to virtually all iron(II)-based probe candidates. Furthermore, the relaxivity data obtained for model MRI-silent and MRI-active chelates, in conjunction with the in vivo behavior of the active form in mice, bode well for a creation of an MRI probe functioning in a true off-on mode.Methodologies and molecular designs described herein enable the development of solution-operating magnetogenic molecular probes, which until now have not been synthesized. The availability of such tools would open up numerous perspectives for technological, environmental and biomedical applications.

A química supramolecular representa o caminho mais promissor na rota de desenvolvimento da nanotecnologia devido à maneira especial com que diferentes moléculas interagem, trocando informações e criando estruturas organizadas. Esta tese pretende contribuir para este campo de pesquisa, através do estudo de três derivados terpiridínicos funcionalizados e seus complexos de ferro(II): 4\'-(3- tienil)- 2,2\':6\',2\'\'-terpiridina (titpy), [Fe(titpy)2]2+; 4\'-(4\'-(fenil)- 2,2\':6\',2\'\'-terpiridina (phtpy), [Fe(phtpy)2]2+ e 4\'-(4-bromo-fenil)-2,2\':6\',2\'\'-terpiridina (Br-phtpy), [Fe(Brphtpy)2]2+. A investigação desses complexos foi realizada por métodos espectroscópicos, físico-químicos e computacionais. As propriedades dos complexos sintetizados foram exploradas empregando o conceito de química supramolecular, através da interação dos mesmos com &#946;-ciclodextrina, matriz de gel de pentóxido de vanádio e nanopartículas de ouro. Os novos materiais gerados apresentaram características que tornam possível a sua aplicação em diferentes áreas como: dosimetria UV-Vís, materiais para baterias e armazenamento de cargas e nanoestruturas organizadas. / Supramolecular chemistry is the most promising path on the development of nanotechnology. This is due to the special way that different molecules interact, exchanging information and generating organized structures. This PhD thesis intends to contribute in the supramolecular research field, with the study of three functionalized terpyridines derivates and the correlated iron(II) complexes: 4\'-(3-thienyl)-2,2\':6\',2\'\'-terpyridine, (titpy), [Fe(titpy)2]2+; 4\'-(4\'-(phenyl)- 2,2\':6\',2\'\'-terpirydine (phtpy), [Fe(phtpy)2]2+ and 4\'-(4-bromophenyl)-2,2\':6\',2\'\'- terpirydine (Br-phtpy), [Fe(Br-phtpy)2]2+. The investigations of the prepared compounds were done by spectroscopy, physicochemical and computational methods. The properties of the synthesized complexes were exploited in the supramolecular chemistry sense by the interactions of those compounds with &#945;-cyclodextrin, vanadium pentoxide gel matrix and gold nanoparticles. The originated materials presented features that make possible the employment of them in distinct areas such: UV-Vis dosimeter, batteries and charge storage, and organized nanostructures

A química supramolecular representa o caminho mais promissor na rota de desenvolvimento da nanotecnologia devido à maneira especial com que diferentes moléculas interagem, trocando informações e criando estruturas organizadas. Esta tese pretende contribuir para este campo de pesquisa, através do estudo de três derivados terpiridínicos funcionalizados e seus complexos de ferro(II): 4\'-(3- tienil)- 2,2\':6\',2\'\'-terpiridina (titpy), [Fe(titpy)2]2+; 4\'-(4\'-(fenil)- 2,2\':6\',2\'\'-terpiridina (phtpy), [Fe(phtpy)2]2+ e 4\'-(4-bromo-fenil)-2,2\':6\',2\'\'-terpiridina (Br-phtpy), [Fe(Brphtpy)2]2+. A investigação desses complexos foi realizada por métodos espectroscópicos, físico-químicos e computacionais. As propriedades dos complexos sintetizados foram exploradas empregando o conceito de química supramolecular, através da interação dos mesmos com &#946;-ciclodextrina, matriz de gel de pentóxido de vanádio e nanopartículas de ouro. Os novos materiais gerados apresentaram características que tornam possível a sua aplicação em diferentes áreas como: dosimetria UV-Vís, materiais para baterias e armazenamento de cargas e nanoestruturas organizadas. / Supramolecular chemistry is the most promising path on the development of nanotechnology. This is due to the special way that different molecules interact, exchanging information and generating organized structures. This PhD thesis intends to contribute in the supramolecular research field, with the study of three functionalized terpyridines derivates and the correlated iron(II) complexes: 4\'-(3-thienyl)-2,2\':6\',2\'\'-terpyridine, (titpy), [Fe(titpy)2]2+; 4\'-(4\'-(phenyl)- 2,2\':6\',2\'\'-terpirydine (phtpy), [Fe(phtpy)2]2+ and 4\'-(4-bromophenyl)-2,2\':6\',2\'\'- terpirydine (Br-phtpy), [Fe(Br-phtpy)2]2+. The investigations of the prepared compounds were done by spectroscopy, physicochemical and computational methods. The properties of the synthesized complexes were exploited in the supramolecular chemistry sense by the interactions of those compounds with &#945;-cyclodextrin, vanadium pentoxide gel matrix and gold nanoparticles. The originated materials presented features that make possible the employment of them in distinct areas such: UV-Vis dosimeter, batteries and charge storage, and organized nanostructures

Femtosecond electron diffraction experiments were performed on solid state iron(II) tris(2,2'-bipyridine) bis(hexafluorophosphate). The cation is known to undergo a spin crossover process when solvated in water and irradiated with 400 nm coherent light which results in a transition from a low spin to high spin state within a picosecond which is accompanied by a uniform 0.2 Å Fe-N bond elongation. A femtosecond diffraction experiment was performed on the solid sample and was unable to find evidence of a fast spin crossover transition. Suspecting this may be due to limitations of the apparatus, an ultrafast transient absorption experiment was performed. Emulating the liquid study by Gawelda et al, the pump probe experiment found evidence of spin crossover in the solid state sample. This result awaits verification by an improved transient absorption apparatus and has inspired efforts to perform an improved femtosecond electron diffraction experiment.

Femtosecond electron diffraction experiments were performed on solid state iron(II) tris(2,2'-bipyridine) bis(hexafluorophosphate). The cation is known to undergo a spin crossover process when solvated in water and irradiated with 400 nm coherent light which results in a transition from a low spin to high spin state within a picosecond which is accompanied by a uniform 0.2 Å Fe-N bond elongation. A femtosecond diffraction experiment was performed on the solid sample and was unable to find evidence of a fast spin crossover transition. Suspecting this may be due to limitations of the apparatus, an ultrafast transient absorption experiment was performed. Emulating the liquid study by Gawelda et al, the pump probe experiment found evidence of spin crossover in the solid state sample. This result awaits verification by an improved transient absorption apparatus and has inspired efforts to perform an improved femtosecond electron diffraction experiment.

L’objet de cette étude est d’utiliser la technique des micelles inverses pour synthétiser des nanoparticules à transition de spin, de taille et de forme contrôlées afin d’en permettre l’utilisation en électronique moléculaire. Dans la première partie, nous avons déterminé les paramètres de synthèse influençant la taille et la forme des particules d’un complexe à transition de spin à fort potentiel d’application. Dans un deuxième temps, nous avons utilisé ces paramètres sur trois autres complexes afin de comprendre la relation entre les paramètres de la synthèse et la morphologie des particules. Les nanoparticules ainsi synthétisées constituent la base d’une discussion sur l’existence d’un lien entre la taille/forme des particules et les propriétés de transition de spin. Enfin, la dernière partie de ce travail est consacrée à l’utilisation de ces matériaux en électronique moléculaire, et l’observation des propriétés de photoconductivité et photovoltaïque à l’échelle des nanoparticules. / The aim of this project is to use the reverse micelles technique to synthesize spin crossover (SCO) nanoparticles with controlled size and shape in order to use them in molecular electronic applications. In the first part, we have determined the synthesis parameters that influence the particles size and shape of an attractive spin crossover complex, due to his potential application. In a second time, we used the determined parameters on three other SCO complexes to generalize the relationship between the synthesis parameters and the particles morphology. All the as-prepared nanoparticles are the basis of a discussion about the existence of a link between the size and/or shape of the particles and the SCO properties. The last part of this work is dedicated to the utilization of this materials in molecular electronic, and the observation of photovoltaic and photoconductive properties at the nanoparticles scale.

A fundamental analysis performed at LKAB is the determination of the iron (II) content of the company’s iron ore products. Currently, a redox titration method using potassium dichromate as the titrator is used to determine this content. However, LKAB is considering replacing its current method due to the titrator’s harmful effects on the health and the environment. The purpose of this study is to compare different redox titration methodsvalidation parameters, to find the most suitable method for the determination of the iron (II) content. The titrators in focus for this study is potassium dichromate, cerium (IV) sulphate and potassium permanganate. Several experiments were performed to compare the three titration methods. The validation parameters determined for each method were precision, accuracy, linearity, LOD, LOQ and robustness. The titration error was also calculated. The results showed that the redox titration with potassium dichromate as the titrator had the highest accuracy at 98.95 %, while the redox titration with cerium (IV) sulphate as the titrator had the best precision at 0.099 % (for samples with a similar matrix as LKAB’s iron ore products). Based on the acquired results, it was concluded that LKAB’s current method is the most suitable for the determination of the iron (II) content in LKAB’s iron ore products. The redox titration method using cerium (IV) sulphate as a titrator is a good competitor, butdue to the method’s slightly inferior accuracy and vague end point, it fails to outcompeteLKAB’s current method. / En grundläggande analys som utförs på LKAB är fastställandet av järn (II)-halten i företagets järnmalmsprodukter. För närvarande används en redox-titreringsmetod med kaliumdikromat som titrator för bestämmelsen av denna halt. LKAB överväger dock att byta ut sin nuvarande metod på grund av titratorns hälso- och miljöfarliga effekter. Syftet med denna studie är att jämföra olika redox-titreringsmetoders valideringsparametrar, för att hitta den mest lämpligaste metoden för fastställandet av järn (II)-halten. De titratorer som studeras är kaliumdikromat, cerium (IV) sulfat och kaliumpermanganat. Flertalet experiment utfördes, för att kunna jämföra de tre titreringsmetoderna med varandra. De valideringsparametrar som bestämdes för vardera metoden var precision, noggrannhet, linjäritet, LOD, LOQ och robusthet. Titrerfelet beräknades också. Resultaten visade att redox-titrering med kalimdikromat som titrator hade högst noggrannhet på 98,95 %, medan redox-titrering med cerium (IV) sulfat som titrator hade bäst precision på 0,099 % (för prover med liknande matris som LKAB:s järnmalmsprodukter). Utifrån de resultat som erhölls så drogs slutsatsen att LKAB:s nuvarande metod är den mest lämpligaste för fastställandet av järn (II)-halten i företagets järnmalmsprodukter. Redox-titreringsmetoden med cerium (IV) sulfat som titrator är en bra konkurrent, men på grund av metodens något sämre noggrannhet och otydligare slutpunkt så misslyckas den med att konkurrera ut LKAB:s nuvarande metod.

Les transitions de spin provoquent des changements de propriétés physiques des complexes de métaux du bloc d les subissant, notamment de leur structure et propriétés spectroscopiques. Ce mémoire porte sur la spectroscopie Raman de composés du fer(II) et du fer(III), pour lesquels on induit une transition de spin par variation de la température ou de la pression. Trois complexes de fer(II) de type FeN4(NCS)2 avec des comportements de transition de spin différents ont été étudiés : Fe(Phen)2(NCS)2 (Phen : 1,10-Phénanthroline), Fe(Btz)2(NCS)2 (Btz : 2,2’-bi-4,5-dihydrothiazine) et Fe(pyridine)4(NCS)2. Un décalage de l’ordre de 50 cm-1 est observable pour la fréquence d’étirement C-N du ligand thiocyanate des complexes FeN4(NCS)2, lors de la transition de spin induite par variation de la température ou de la pression. Il est possible d’utiliser cette variation de fréquence afin de tracer un profil de transition. Quatre complexes isomères de type FeL222(CN)2 (L222 : 2,13- diméthyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]-octadéca-1(18),2,12,14,16-pentaène) ont également été étudiés. Un taux de décalage de l’ordre d’environ 0,03 cm-1/K est observé pour plusieurs bandes du complexe FeL222(CN)2. La bande à 1415 cm-1 disparaît à plus haute température au profit d’une bande à 1400 cm-1. Pour le complexe de chiralité R,R’, les bandes à 1008 cm-1 et 1140 cm-1 se déplacent vers des fréquences plus élevées à partir de 223 K. Les transitions de spin sont observées dans certains complexes de fer(III). Dans cette famille de composés, le complexe Fe(EtDTC)3 (EtDTC : N,N-diéthyldithiocarbamate) a été étudié . Aucun changement n’a été observé dans l’intensité des bandes d’étirement fer-soufre sur les spectres à température variable. Cependant, la bande Fe-S associée à la forme bas-spin à 530 cm-1 augmente en intensité au profit de la bande associée à la forme haut-spin à 350 cm-1 lors des mesures à haute pression, passant d’un rapport d’amplitude de 50% à pression ambiante à 80% à 21 kbar. Un dédoublement de la bande d’étirement C-N du ligand dithiocarbamate à 1495 cm-1 est également observé à des pressions supérieures à 5 kbar. Une comparaison des changements des fréquences de vibration de tous les complexes est effectuée. / AbstractSpin crossover processes lead to significant changes of molecular structures and spectroscopic properties measured for complexes of d-block transition metals. This thesis focuses on vibrational Raman spectroscopy of iron(II) and iron(III) compounds with spin transitions induced through temperature and pressure variations. Three iron(II) complexes of type FeN4(NCS)2 with different spin transition patterns have been studied: Fe(Phen)2(NCS)2 (Phen : 1,10-Phenanthroline), Fe(Btz)2(NCS)2 (Btz : 2,2’-bi-4,5- dihydrothiazine) and Fe(pyridine)4(NCS)2. A 50 cm-1 shift has been found for the C-N stretching frequency of the thiocyanate ligand in these compounds as a consequence of the spin transition induced by temperature or pressure. These frequency variations have been used to trace different transition profiles. Four different isomers of FeL222(CN)2 (L222 : [2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]-octadeca-1(18),2,12,14,16- pentaene]) type complexes have also been studied. A variation with temperature of approximately 0,03 cm-1/K has been observed for a few bands for the FeL222(CN)2 complex. A band at 1415 cm-1 decreases in intensity in favour of a band at 1400 cm-1 as temperature rises. The bands at 1008 cm-1 and 1140 cm-1 for the complex of R,R’ configuration shift to higher frequencies around 223 K. Spin transitions have also been investigated in some iron(III) complexes. In this family of compounds, the Fe(EtDTC)3 (EtDTC : N,N-diéthyldithiocarbamate) complex has been studied. No change has been observed in the intensity of the iron-sulphur stretching bands in spectra measured at variable temperature. However, at high pressure the low-spin Fe-S band at 530 cm-1 gains intensity compared to the high spin band at 350 cm-1. A splitting of the C-N stretching band of the dithiocarbamate ligand at 1495 cm-1 is observed at pressures above 5 kbar. A comparison of all changes in vibrational spectra is presented.