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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
551

Analyzing the Performance of Lithium-Ion Batteries for Plug-In Hybrid Electric Vehicles and Second-Life Applications

January 2017 (has links)
abstract: The automotive industry is committed to moving towards sustainable modes of transportation through electrified vehicles to improve the fuel economy with a reduced carbon footprint. In this context, battery-operated hybrid, plug-in hybrid and all-electric vehicles (EVs) are becoming commercially viable throughout the world. Lithium-ion (Li-ion) batteries with various active materials, electrolytes, and separators are currently being used for electric vehicle applications. Specifically, lithium-ion batteries with Lithium Iron Phosphate (LiFePO4 - LFP) and Lithium Nickel Manganese Cobalt Oxide (Li(NiMnCo)O2 - NMC) cathodes are being studied mainly due to higher cycle life and higher energy density values, respectively. In the present work, 26650 Li-ion batteries with LFP and NMC cathodes were evaluated for Plug-in Hybrid Electric Vehicle (PHEV) applications, using the Federal Urban Driving Schedule (FUDS) to discharge the batteries with 20 A current in simulated Arizona, USA weather conditions (50 ⁰C & <10% RH). In addition, 18650 lithium-ion batteries (LFP cathode material) were evaluated under PHEV mode with 30 A current to accelerate the ageing process, and to monitor the capacity values and material degradation. To offset the high initial cost of the batteries used in electric vehicles, second-use of these retired batteries is gaining importance, and the possibility of second-life use of these tested batteries was also examined under constant current charge/discharge cycling at 50 ⁰C. The capacity degradation rate under the PHEV test protocol for batteries with NMC-based cathode (16% over 800 cycles) was twice the degradation compared to batteries with LFP-based cathode (8% over 800 cycles), reiterating the fact that batteries with LFP cathodes have a higher cycle life compared to other lithium battery chemistries. Also, the high frequency resistance measured by electrochemical impedance spectroscopy (EIS) was found to increase significantly with cycling, leading to power fading for both the NMC- as well as LFP-based batteries. The active materials analyzed using X-ray diffraction (XRD) showed no significant phase change in the materials after 800 PHEV cycles. For second-life tests, these batteries were subjected to a constant charge-discharge cycling procedure to analyze the capacity degradation and materials characteristics. / Dissertation/Thesis / Masters Thesis Materials Science and Engineering 2017
552

Formation et surfusion de gouttes d'alliage eutectique AuSi sur substrats de Si : étude in situ par rayonnement synchrotron X / Formation and supercooling of AuSi eutectic droplets on Si substrates : an in-situ study using synchrotron radiation

Daudin, Rémi 10 February 2012 (has links)
Les nanofils (NFs) de semi-conducteur (SC) sont des objets possédant des propriétés très intéressantes pour la fabrication de futurs composants électroniques à l'échelle nanométrique. Ils sont élaborés grâce à l'utilisation d'un catalyseur métallique (Au) formant un point eutectique profond en s'alliant à la phase SC (Si) permettant la germination et la croissance du NF à basses températures. Ce travail a pour but l'étude de la formation, de la structure et du comportement de ces gouttes d'alliage eutectique en interaction avec le substrat dont les propriétés futures du NF vont dépendre. L'étude a été menée in-situ, par utilisation du rayonnement synchrotron qui est un outil parfaitement dédié à la caractérisation de structures à l'échelle atomistique. Les gouttes d'eutectique ont été obtenues par le démouillage d'un film d'or. L'étude de ce procédé a révélé des changements dans les relations d'épitaxies entre l'or et le silicium. Les gouttes ainsi formées sont accompagnées d'une couche de mouillage, se révélant être une reconstruction de surface, dont les conditions de formation ainsi que la structure atomique ont été déterminées. Lors du refroidissement, une augmentation des effets de surfusion a été observée en présence de cette reconstruction et sont expliqués par la structure même de cette dernière qui semble stabiliser l'état liquide. Des expériences similaires ont été faites sur d'autres systèmes (Au-Ge, Al-Si) et une synthèse a été réalisée pour comparer les connaissances actuelles sur le ce sujet avec les résultats de ce travail. / Semiconductor (SC) nanowires (NMs) have been identified as important components for future electronic and sensor nanodevices. They are produced using a metal catalyst (Au) that forms a low eutectic point with the SC phase (Si) and enables their nucleation and their growth at low temperatures. The aim of this study is to investigate the formation, the structure as well as the behaviour of such liquid eutectic droplets in interaction with the substrates on which the futur NMs properties will later depend. This work has been performed in-situ, using synchrotron radiation which is the perfect tool to characterize this mechanism at the atomistic scale. The eutectic droplets have been obtained through the dewetting of thin gold films. This process has been found to modify the epitaxial relationships between the gold and the silicon substrate. The obtained droplets are accompanied by a wetting layer (WL) whose conditions of formation as well as atomic structure, which turned to be a surface reconstruction, have been determined. During the cooling process, the supercooling effects in such AuSi eutectic droplets have been found to be enhanced in the presence of this reconstruction. They are explained by the specific structure of the reconstruction which is likely to stabilize the liquid phase. Similar experiments on other systems (Au-Ge or Al-Si) were performed and a synthesis has been made in order to present the current knowledge on this topic in comparison with the results of this work.
553

Croissance et caractérisation de nanofils de GaN et d'hétérostructures filaires de GaN/AIN / Growth and characterization of GaN nanowires and GaN/AlN heterostructure nanowires

Hestroffer, Karine 25 October 2012 (has links)
Ce travail de thèse porte sur la croissance par épitaxie par jets moléculaires assistée plasma et sur la caractérisation de nanofils (NF) de GaN et d'hétérostructures filaires de GaN/AlN. Dans un premier temps, la morphologie des NFs de GaN (densité, longueur moyenne, diamètre moyen, dispersion de longueurs) est étudiée en fonction des paramètres de croissance. Via la diffraction d'électrons rapides, la morphologie des NFs GaN est corrélée à la dynamique de nucléation de ces derniers. Des expériences de diffraction de rayons X en incidence rasante effectuées à l'ESRF permettent également de clarifier les processus de nucléation des NFs GaN. Nous démontrons ensuite l'utilisation de la diffraction de rayons X résonnante pour déterminer la polarité des NFs GaN. Nous montrons que ces derniers sont de polarité N lorsque fabriqués sur Si nu. Des tests complémentaires de gravure sélective au KOH révèlent que les NFs GaN fabriqués sur un substrat de Si recouvert d'un fin buffer d'AlN ainsi que ceux dont la fabrication est initiée après pré-déposition de Ga sur la surface du Si, sont aussi de polarité N. Concernant les hétérostructures filaires GaN-AlN, la croissance d'AlN autour et sur les nanofils de GaN est étudiée en fonction de divers paramètres de croissance. Le rapport d'aspect des coquilles d'AlN (longueur/épaisseur) est décrit par un modèle géométrique. En utilisant une combinaison de diffraction anomale multi-longueurs d'onde, de microscopie en transmission de haute résolution et des calculs théoriques, l'état de contrainte des coeurs de GaN est analysé en fonction de l'épaisseur de la coquille. Cette contrainte augmente avec l'épaisseur de la coquille tant que l'AlN croît de manière homogène autour des NFs de GaN. Dès lors que la coquille est asymétrique, le système relaxe plastiquement. Nous étudions enfin la possibilité de fabriquer des îlots de GaN dans des NFs AlN. Nous déterminons le rayon critique de NFs AlN au-dessus duquel le GaN déposé subit une transition de forme de 2D à 3D. L'analyse des propriétés optiques de ces nanostructures originales revèle la présence de nombreux états localisés. / This work focuses on the growth by plasma-assisted molecular beam epitaxy and on the characterization of GaN nanowires (NWs) and of GaN/AlN NW heterostructures. We first investigate GaN NW morphology (density, mean length, mean diameter, length dispersion) dependence on the growth parameters. Using reflection high energy electron diffraction, GaN NW morphology is correlated to their nucleation dynamics. In situ grazing-incidence X-ray diffraction experiments performed at the ESRF allow clarifying GaN NW nucleation processes on bare Si(111) and when usinga thin AlN buffer deposited on Si(111). The use of resonant X-ray diffraction for the determination of GaN NW polarity is then successfully demonstrated. GaN NWs grown on bare Si(111) are shown to be N-polar. Additional KOH selective etching tests reveal that both GaN NWs grown using a thin AlN buffer on Si(111) and when pre-depositing Ga on the Si(111) surface are N-polar, too. Regarding GaN-AlN NW heterostructures, the growth of an AlN shell around GaN NWs is studied as a function of various growth parameters. The AlN shell aspect ratio is described by a geometrical model. Using a combination of multiwavelength anomalous diffraction, high resolution transmission microscopy and theoretical calculations, GaN core strain state is investigated as a function of the AlN shell thickness. This strain is shown to increase with the shell thickness as long as AlN grows homogeneously around GaN NWs. When the shell is asymmetric, the system relaxes plastically. Eventually, we study the possibility to fabricate island-like GaN insertions in AlN NWs. We determine the critical AlN NW radius above which GaN undergoes a 2D to 3D shape-transition. Regarding optical properties of these novel structures, the presence of multiple localized states is identified.
554

Couches minces de langasite pour applications piézoélectriques : élaboration par chimie douce et caractérisation / Langasite thin layer for piezoelectric applications : soft chemistry elaboration and caracterisation

Mevel, Mehdi 10 December 2014 (has links)
L'objectif de cette thèse est l'élaboration de couche mince piézoélectrique sans plomb pour des applications mécatroniques. Le matériau piézoélectrique sélectionné est la langasite, La3Ga5SiO14, qui conserve ses propriétés à haute température (Tfus = 1470°C). L'élaboration par chimie douce permet une mise œuvre simple et économique. De nombreuses synthèses ont été réalisées variant précurseurs, ligands et solvants Des analyses thermogravimétriques et thermiques différentielles complétées par des caractérisations par spectroscopie infrarouge ont permis de comprendre les étapes de décompositions des précurseurs pour les différentes synthèses. Ainsi les précurseurs chlorures ne permettent pas la formation de langasite pure puisque restant dans la sphère de coordination du lanthane jusqu'à haute température. Nous avons retenu une synthèse à base de précurseurs nitrates permettant la formation d'une solution stable, nécessaire pour la réalisation de dépôts et conduisant à la formation de la langasite pure. Pour être piézoélectrique une couche mince doit être texturée dans une direction correspondant à une direction piézoélectrique du matériau. L'objectif de la thèse était au départ de déposer la langasite sur un substrat souple bitexturé de Ni95W5/LZO. Tous les essais de dépôts ont conduit à l'oxydation de ce substrat, même sous atmosphère inerte, d'autres substrats ont donc été étudiés. Les films obtenus ont essentiellement été caractérisés par diffraction des rayons X en mode tetha/2tetha, phi scan et figures de pôles. Des études par microscopie électronique à transmission ont également été menées. La morphologie des dépôts a été caractérisée par AFM. Les essais sur MgO (111) ou Si (100) ont conduit à la formation d'une couche mince de langasite polycristalline. Le dépôt de langasite sur MgO (100) possède une orientation préférentielle des plans (110) et (101). Des dispositifs SAW réalisés sur plusieurs couches n'ont pas permis de mettre en évidence des propriétés piézoélectriques. La dégradation de la langasite dans les films a ensuite été mise en évidence et peut expliquer ces résultats. Les dépôts de langasite sur spinelle MgAl2O4, présentent une texture fibrée des plans (002). Les perspectives de ces travaux concernent la mesure des coefficients piézoélectriques des dépôts sur spinelle ainsi que des essais de dépôt d'une couche métallique sur la surface des films afin de les protéger et éviter ainsi leur dégradation. / The objective of this PHD is the development of piezoelectric thin layers without lead element. The selected piezoelectric material is the langasite, La3Ga5SiO14, which keeps its piezoelectric properties at very high temperature (Tm = 1470°C). The chosen langasite synthesis is a soft chemistry way which is economical and easy to work. We have made many tests with different metal precursors, different solvents and ligands. Infrared spectroscopy, X-ray diffraction, differential thermal analysis and thermogravimetric analysis were done to study the decompositions steps. Thus, the synthesis with chlorides precursors lead to impure langasite due to chloride atoms which stay in the coordination sphere of lanthanum at high temperature. We selected a based nitrate synthesis which allows the formation of stable solution leading to pure langasite. To be piezoelectric, a thin layer must be a textured layer, and the orientation of the texture must be a piezoelectric direction. To depose langasite on flexible bitextured substrate of Ni95W5 / LZO was the first aim of this PHD. All tests led to the oxidation of this substrate. Further to these results other substrates were studied. The films were analyzed by X ray diffraction in (theta/2theta), phi scan and pole figures. The morphology of the layers was studied by AFM. Tests on MgO (111) or Si (100) led to the formation of polycrystalline langasite thin Layer. Deposition of langasite on MgO (100) led to two preferred orientation (110) and (101) . SAW electrodes were deposited on these layers but any piezoelectric properties were measured. Further degradation of films has been shown. Depositions on spinel MgAl2O4 , present a fibrous texture of the (002) planes . The prospects of this work concern the piezoelectric coefficients measurement of spinel deposit. Depositions tests of a metallic layer to protect the films langasite from degradation have to be made.
555

Etudes structurales des conducteurs organiques bidimensionnels à haute pression / Structural studies of two-dimensional organic conductors at high pressures

Brun, Sulyvan 19 December 2013 (has links)
Les conducteurs organiques à base du sel de transfert de charge bis(éthylènedithio)tétrathiafulvalène (BEDT-TTF ou ET) montrent un comportement électrique allant de semi-conducteur à métal supraconducteur. La pression peut induire des petits changements structuraux qui s'accompagnent de changements très important des propriétés physiques. L'étude de l'évolution de la structure de ces composés sous pression, dont les mailles sont de faible symétrie contenant plusieurs dizaines d'atomes légers, constitue un défi. Le but de ce travail est d'étudier ces changements structuraux induits par la pression en utilisant la diffraction des rayons X sur monocristaux. Les monocristaux de six conducteurs et supraconducteurs organiques (α-(BEDT-TTF)2I3, β-(BEDT-TTF)2I3, κ-(BEDT-TTF)2I3, α-(BEDT-TTF)2KHg(SCN)4, κ-(BEDT-TTF)2Cu(NCS)2, et κ-(BEDT-TTF)2Cu[N(CN)2]Br) ont été étudiés à haute pression (jusqu'à 32 GPa) dans une cellule à enclumes de diamant sur la ligne de lumière ID09A à l'ESRF. L'hélium a été utilisé comme milieu transmetteur de pression. Les compressibilités de ces six composés ainsi que leurs positions atomiques ont été déterminées sous pression. Pour la première fois, les transitions de phases structurales réversibles de α-(BEDT-TTF)2I3 vers αHP-(BEDT-TTF)2I3 à 13.6 GPa, et de κ-(BEDT-TTF)2Cu(NCS)2 vers κHP-(BEDT-TTF)2Cu(NCS)2 à 8.5 GPa ont été observées, et les structures originales à haute pression ont été décrites avec succès. Les changements structuraux observés ont été appuyés par des mesures Raman. / Organic conductors based on charge-transfer salt of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) exhibit electronic properties ranging from semiconducting to metallic to superconducting. Pressure can induce subtle structural rearrangements associated with drastic changes in physical properties. Study of the pressure induced structural changes of these compounds, with low symmetry unit cells containing dozens of light atoms, is a challenge. The aim of this work is to investigate pressure-induced structural changes with single crystal X-ray diffraction. Single-crystals of six organic conductors and superconductors (α-(BEDT-TTF)2I3, β-(BEDT-TTF)2I3, κ-(BEDT-TTF)2I3, α-(BEDT-TTF)2KHg(SCN)4, κ-(BEDT-TTF)2Cu(NCS)2, and κ-(BEDT-TTF)2Cu[N(CN)2]Br) were studied at high-pressures (up to 32 GPa) in a diamond-anvil cell on the ID09A beamline at the ESRF. Helium was used as pressure transmitting-medium. The compressibilities of the six compounds are reported, and atomic positions were determined under pressure. For the first time, reversible structural phase transitions in α-(BEDT-TTF)2I3 to αHP-(BEDT-TTF)2I3 at 13.6 GPa, and in κ-(BEDT-TTF)2Cu(NCS)2 to κHP-(BEDT-TTF)2Cu(NCS)2 at 8.5 GPa have been observed, and the original high pressure structures have been described successfully. Raman measurements agree well with the observed structural changes.
556

Experimental and computational magnetic resonance studies of selected rare earth and bismuth complexes

Gowda, V. (Vasantha) 16 October 2017 (has links)
Abstract The rare-earth elements (REEs) and bismuth, being classified as the ‘most critical raw materials’ (European Raw Materials Initiatives, 2017), have a high economic importance to the EU combined with a high relative supply risk. REEs are highly important for the evolving technologies such as clean-energy applications, high-technology components, rechargeable batteries, permanent magnets, electric and hybrid vehicles, and phosphors monitors. This scientific research work aims at building a fundamental knowledge base concerning the electronic/molecular structure and properties of rare-earth element (REE) and bismuth complexes with dithiocarbamate (DTC) and 1,10-phenanthroline (PHEN) by employing state-of-the-art experimental techniques such as nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction (XRD) techniques together with ab initio quantum mechanical computational methods. This combination of methods has played a vital role in analysing the direct and significant effect of the heavy metal ions on the structural and magnetic resonance properties of the complexes, thereby, providing a framework of structure elucidation. This is of special importance for REEs, which are known to exhibit similar chemical and physical properties. The objectives of the work involve i) a systematic investigation of series of REE(III) as well as bismuth(III) complexes to get a profound understanding of the structure-properties relationship and ii) to find an appropriate theoretical modelling and NMR calculation methods, especially, for heavy metal systems in molecular and/or solid-state. This information can later be used in surface interaction studies of REE/bismuth minerals with DTC as well as in design and development of novel ligands for extraction/separation of metal ions. The REE(III) and bismuth(III) complexes with DTC and PHEN ligands have all provided a unique NMR fingerprint of the metal centre both in liquid and solid phase. The solid-state ¹³C and ¹⁵N NMR spectra of the diamagnetic REE(III) and bismuth(III) complexes were in accord with their structural data obtained by single crystal XRD. The density functional theory (DFT) methods were used to get complementary and refined structural and NMR parameters information for all diamagnetic complexes in the solid-state. The relativistic contributions due to scalar and spin-orbit correlations for the calculated ¹H/¹³C/¹⁵N chemical shifts of REE complexes were analysed using two-component zeroth-order regular approximation (ZORA)/DFT while the ‘crystal-lattice’ effects on the NMR parameters were calculated by combining DFT calculations on molecular and periodic solid-state models. The paramagnetic REE complexes display huge differences in their ¹H and ¹³C NMR spectral patterns. The experimental paramagnetic NMR (pNMR) chemical shifts, as well as the sizable difference of the ¹H and ¹³C NMR shifts for these isoelectronic complexes, are well reproduced by the advanced calculations using ab initio/DFT approach. The accuracy of this approach is very promising for further applications to demanding pNMR problems involving paramagnetic f-block elements. The results presented in this thesis demonstrate that a multidisciplinary approach of combined experimental NMR and XRD techniques along with computational modelling and property calculations is highly efficient in studying molecular complexes and solids containing heavy metal systems, such as rare-earths and bismuth.
557

Estudo da transição cristalográfica em filme fino de VO2 por difração de raios-x / Study of the crystallographyc transition in thin films of VO2 by x-ray diffraction

Escobar, Vivian Montardo 28 March 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In one sample, X-Ray diffractions have been measured as a function of the temperature, in order to follow the crystallographic transition experienced by VO2 near 68ºC. The results have been analysed with the aide of a software based in the Rietveld structure refinement method. Below the critical temperature, the material is in a monoclinic M1 phase, with the V-V dimers parallel to the substrate. Near transition temperature, is has been identified a coexistence of the M1 and R phases, separated by a M2 region. The coexistence occurs inside individual grains. In contrast with the M1 and R phases, frequently identified in the VO2 transition, this is the first time the M2 phase is reported in < 011 > textured polycrystalline films of VO2 deposited by magnetron sputtering. A comparison between the M1 and R peaks width, at room temperature and (95ºC) respectively, shows the M1 phase is under inhomogeneous stress. Although in average those stresses are tensile, an important fraction of the sample is under compressive stress, what could explain the presence of the M2 phase. / Características estruturais e morfológicas de filmes de óxido de vanádio depositados pela técnica de magnetron sputtering reativo foram determinadas por difração de RX. Os filmes estudados, isentos de qualquer contaminação com outras estequiometrias, são constituídos de grãos relativamente grandes e estão fortemente texturizados com a direção < 011 > praticamente perpendicular ao substrato. Em uma amostra foram extraídos difratogramas em função da temperatura para acompanhar a transição cristalográfica que o VO2 sofre próximo a temperatura de 68ºC. Os resultados obtidos para as diferentes temperaturas foram analizados com o auxílio de um software baseado no método Rietveld de refinamento de estruturas. Para temperaturas abaixo da temperatura crítica para a transição, o material apresentou-se na fase monoclínica M1 com os dímeros de vanádio alinhados paralelos ao substrato. Na faixa de temperaturas que compreende a transição, há uma coexistência das fases M1 e R separadas por uma monoclínica M2. Esta coexistência ocorre dentro de grãos individuais da amostra. Ao contrário das fases M1 e R, que normalmente são identificadas na transição do VO2, esta é a primeira vez em que a fase M2 é observada em filmes finos policristalinos depositados por sputtering com textura < 011 >. A comparação entre as larguras dos picos da fase M1 (temperatura ambiente) e da fase rutila R (95ºC) mostra que a fase M1 está sujeita a estresses não homogêneos. Embora na média esse estresse seja tênsil, uma parte apreciável dos cristais se mostra sob estresse compressivo, parte esta que explica o surgimento da fase M2.
558

Estudo cristalino, molecular, supramolecular e de \" Docking\" de alguns compostos derivados de quinonas / Crystal structure, molecular, supramolecular and docking studies of some substituted quinones

Antonio Carlos Trindade 21 June 2006 (has links)
Neste trabalho são apresentados os resultados das determinações cristalinas, estruturais e supramoleculares, por difração de raio X, bem como os estudos de \"docking\" , de oito compostos derivados da 1,4-quinona. As estruturas resolvidas e refinadas mostraram a existência de ligações de hidrogênio, não convencionais intra e intermoleculares. Estas últimas permitiram entender o empacotamento cristalino em cada composto. Os resultados cristalográficos foram comparados com aqueles encontrados na literatura. Mas as estruturas correspondentes aos compostos AC1 (6,7-bis-fenilsulfanil-1,4-dihidro-1,4-metano-naftaleno-5,8-diona) e AC6 (6,7-bis-metilsulfanil-1,4-dihidro-1,4-metano-naftaleno-5,8-diol) possuem esqueletos químicos ainda não descritos na cristalografia. Os estudos de \"docking\" foram realizados utilizando as conformações cristalográficas dos oito compostos e da estrutura cristalográfica da tripanotiona redutase, uma proteína, dimérica, envolvida no sistema anti-stress oxidativo no Tripanosoma cruzi, parasita responsável pela enfermidade de Chagas. Foram, então, gerados complexos proteína-ligante no sítio da interface entre monômeros. Os complexos resultantes foram agrupados de acordo com orientações preferenciais e em cada grupo, a estrutura com menor energia total foi selecionada como representante do conjunto e analisado em tela gráfica. Para cada uma das moléculas foram realizados estudos detalhados das suas interações com todos os aminoácidos que as rodeavam. Finalmente, levando em conta as energias envolvidas e as interações foi possível escolher aquela que mostra o melhor encaixe. Dentre todas as moléculas, a AC8 [4a,8a-Dicloro-6-etilsulfanil-7-(metiletil-fenil-amino)-1,4,4a,8a-tetrahidro-1,4-metano-naftaleno-5,8,-diona] foi considerada como a mais promissora, a qual apresentou melhores resultados, um maior número de interações favoráveis com menor energia. / In this work the results of the crystal structure and supramolecular determination by X-ray diffraction together with docking studies, of eight compounds derived from 1,4-quinone, are presented. The solved and refined structures showed the existence of non-conventional hydrogen bonds, intra and inter-molecular. These last ones gave an insight about the crystal packing in each compound. The crystallographic results have been compared with those found in the literature. It should pointed out that structures of compounds AC1 (6,7-bis-phenylsulfanyl-1,4-dihydro-1,4-methano-naphthalene-5,8-dione) and AC6 (6,7-bis-methylsulfanyl-1,4-dihydro-1,4-methane-naphthalene-5,8-diol) have chemical skeletons which were not described before in crystallography. The docking studies have been carried out using the crystallographic conformations of the eight compounds and the crystallographic structure of trypanothione reductase, a dimmeric protein, involved in the anti-stress oxidative system of the Trypanosoma cruzi, the parasite responsible for the Chagas disease. The compounds were docked in the dimmer interface, which is the most likely binding site. The resulting complexes have been clustered together according with their orientation and of each group the one with the lowest total energy was chosen as representative of the cluster and analyzed in graphical screen. Thus, for that complex a detailed study of its interactions with all the neighbor amino acids was done. Finally, taking in account the energies and the interactions it was possible to choose the one that showed the best docking result. Amongst all molecules, the AC8 [4a,8a-dicloro-6-etilsulfanil-7-(metiletil-fenil-amino)-1,4,4a,8a-tetrahidro-1,4-methane-naftaleno-5,8,-diona] was considered as the most promising, which presented better results, a bigger number of favorable interactions with lesser energy.
559

Avaliação da auto-associação molecular de complexos metálicos com ligantes triazenidos derivados do 1,3-bis(fenil)triazeno / Evaluation of the molecular autoassociation of metallic complexes with triazenide derived from 1,3-bis (phenyl)triazene

Villis, Paulo Cesar Mendes 13 September 2007 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents the synthesis and the investigation of the crystalline and molecular structure of 1,3-bis(2-methoxy-4-nitrophenyl)triazene ethanol and seventeen new mononuclear or binuclear complexes of Cu(I), Cu(II), Tl(I), Hg(II), Ag(I), Ni(II), Zn (II) with monocatenated triazenide ligands derived from the 1,3-bis(phenyl)triazene. The coordination of metallic ions by triazenido compounds had been studied in the solid state. We studied the relations that make possible the formation of intramoleculares and intermoleculares interactions, that could show supramolecular arrangements unidimensionais, bidimensional and until three-dimensional. Other eight ligands had been synthesized and we investigated its physical and molecular properties: 1,3-bis (3-nitrophenyl)triazene, 1,3-bis(4-methoxycarbonylphenyl)triazene, 1,3-bis(4-ethoxycarbonylphenyl)triazene, 1,3-bis(4-chlorophenyl)-triazene, 1-(phenyl)-3-(4-nitrophenyl)triazene, 1-(4-chlorophenyl)-3-(4-nitrophenyl)triazene, 1-(2-methoxy-4-nitrophenyl)-3-(2,4-dibromophenyl)triazene and 1-(4-nitrophenyl)-3-(2-pyrimidinyl) triazene. We used techniques of Infrared Absorption Spectroscopy, Spectrometry of Nuclear Magnetic Resonance, Melting Point and Elementary Analysis CHN in this study. The variety in the geometry of coordination of the 1,3-bis(2-methoxy-4-nitrophenyl)triazene can be used to depicted its versatility to form complexes with many metallic ions, beyond presenting a variety of chemical and spectroscopic properties. The complexes {Cu[CH3O(NO2)C6H3NNNC6H3(NO2)OCH3]}4(CH3CN)4 (1), {Cu[CH3O(NO2)C6H3NNNC6H3(NO2)OCH3(C5H5N)2(N3)]}(3) and {Cu[CH3O(O2N)C6H3NNNC6H3(NO2)OCH3-(C5H5N)2(CH3COO)]} (4), using the copper ion (I and II) had been characterized by Spectroscopy of Electronic Paramagnetic Resonance, Electronic and Electrochemical Spectroscopy. All these complexes of Cu (II) had presented interesting magnetic and electrochemical properties. / Este trabalho apresenta a síntese e a investigação da estrutura cristalina e molecular do préligante 1,3-bis(2-metoxi-4-nitrofenil)triazeno etanol e de dezessete novos complexos mononucleares e binucleares de Cu(I), Cu(II), Tl(I), Hg(II), Ag(I), Ni(II), Zn(II) com ligantes triazenídicos monocatenados derivados do 1,3-bis(fenil)triazeno. Estudou-se compostos triazenídicos coordenados a íons metálicos em estado sólido, avaliando-se as interações que possibilitam a formação de ligações não-clássicas intra e intermoleculares, resultando os arranjos supramoleculares unidimensionais, bidimensionais e até tridimensionais. Outros oito pré-ligantes foram sintetizados e investigados as suas propriedades físicas e moleculares: 1,3-bis(3-nitrofenil)triazeno, 1,3-bis(4-metoxicarbonilfenil)triazeno, 1,3-bis(4-etoxicarbonilfenil)-triazeno, 1,3-bis(4-clorofenil)triazeno, 1-(fenil)-3-(4-nitrofenil)triazeno, 1-(4-clorofenil)-3-(4-nitrofenil)triazeno, 1-(2-metoxi-4-nitrofenil)-3-(2,4-dibromofenil)triazeno e 1-(4-nitrofenil)-3-(2-pirimidinil)triazeno; utilizando técnicas de Espectroscopia de Infravermelho, Espectrometria de Ressonância Magnética Nuclear de Prótons, Ponto de Fusão e Análise Elementar CHN. A variedade de modo de coordenação que o pré-ligante 1,3-bis(2-metoxi-4-nitrofenil)triazeno pode exemplificar, destaca-se pela sua versatilidade de formar complexos com diversos íons metálicos, além de apresentar uma gama de propriedades químicas e espectroscópicas. Os complexos {Cu[CH3O(NO2)C6H3NNNC6H3(NO2)OCH3]}4(CH3CN)4 (1), {Cu[CH3O(NO2)C6H3N-NNC6H3(NO2)OCH3(C5H5N)2(N3)]} (3) e {Cu[CH3O(O2N)C6H3NNNC6H3(NO2)OCH3(C5H5N)2(CH3COO)]} (4) envolvendo o íon de cobre (I e II) foram caracterizados por Espectroscopia de Ressonância Paramagnética Eletrônica, Espectroscopia Eletrônica e Eletroquímica. Todos estes complexos de Cu(II) apresentaram interessantes propriedades magnéticas e eletroquímicas.
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Síntese e análise estrutural de compostos derivados de calcogenolatos metálicos MER (M = HgII, PdII; E = Se, Te; R = aril) / Synthesis and structural analysis of compounds derivatives from metal chalcogenolates MER (M = HgII, PdII; E = Se, Te; R = aryl)

Tirloni, Bárbara 18 January 2013 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work presents a study related to the synthesis and structural analysis of compounds derivatives from metal chalcogenolates - MER (M = HgII, PdII; E = Se, Te; R = aryl). In the first step of this work were investigated reactions of Hg(SePh)2 with HgII halides, that led to the formation of a series of binary compounds. In the second step, it was planned to obtain heterometallic compounds, with the incorporation of a second metal (M) in the structure of the compound. For this, we explored reactions of Hg(TeR)2 (R = Ph, Mes, (2,6- OCH3)2C6H3) with different PdII salts. These reactions led to the formation of one ternary compound {HgTePd} and four binary compounds, whereas three of them have the core made up of {TePd} and one of {TeHg}. In the third step, this work was focused on exploring reactions of (ER)2 with PdII and HgII salts. These reactions led to the E-E bond cleavage and the formation of compounds derivatives from metal chalcogenolates with different structures. A structural study in the solid state of all compounds was carried out using single crystal Xray diffraction. Other analytical methodologies such as elemental analysis and infrared spectroscopy were also used for the characterization of the compounds. The ultraviolet-visible spectroscopy supported the measurement of the optical band gap in the solid state for the compounds obtained. / Este manuscrito apresenta o estudo relacionado à síntese e análise estrutural de compostos derivados de calcogenolatos metálicos MER (M = HgII, PdII; E = Se, Te; R = aril). Na primeira etapa deste trabalho investigou-se reações de Hg(SePh)2 frente à haletos de HgII, que levaram à formação de uma série de compostos binários. Em um segundo momento, planejou-se obter compostos heterometálicos frente à incorporação de um segundo metal (M) na estrutura do composto. Para isso buscou-se explorar reações do Hg(TeR)2 (R = Ph, Mes, (2,6-OCH3)2C6H3) com diferentes sais de PdII. Essas reações levaram à formação de um composto ternário {HgTePd} e quatro compostos binários, sendo que três deles apresentam o núcleo constituído por {TePd} e um por {TeHg}. Em um terceiro momento, este trabalho deteve-se em explorar reações envolvendo o (ER)2 frente à sais de PdII e HgII. Essas reações levaram à clivagem da ligação E-E e a formação de compostos derivados de calcogenolatos metálicos com estruturas diferenciadas. Efetuou-se um estudo estrutural no estado sólido de todos compostos obtidos, utilizando como ferramenta principal a difração de raios X em monocristal. Outras metodologias de análise como análise elementar e espectroscopia no infravermelho também foram utilizadas para a caracterização dos compostos. A espectroscopia no ultravioleta-visível auxiliou na determinação do band gap no estado sólido dos compostos obtidos.

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