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Saywell, Alexander. « 2D organisation of complex organic molecules ». Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/14588/.
Texte intégralRésumé :
The self-assembly of two-dimensional molecular systems is of significant interest, offering an insight into the fundamental interactions which drive the formation of complex supramolecular structures. A careful choice of the molecular 'building blocks' for such self-assembled systems potentially allows the design and production of nanoscale architectures with pre-determined geometries and specific chemical functionalities. Within this thesis the two-dimensional structures formed by the self-assembly of complex organic molecules, deposited on an Au(111) surface held in an ultrahigh vacuum (URV) environment, are studied using a combination of scanning tunnelling microscopy (STM), photoelectron spectroscopy (PES), molecular dynamics (MD), and density functional theory (DFT) techniques. A UHV electrospray deposition (URV-ESD) technique is employed to facilitate the introduction of thermally labile molecules into the URV environment. Bi-molecular networks, formed from perylene tetracarboxylic diimide (PTCDI) and melamine, have previously been observed to assemble on the Au(111) surface. Several more complex phases are reported here, as characterised by S'I'M, with the balance between isotropic and anisotropic interactions giving rise to a variety of structures. Chemical functionality may be added to these networks by incorporating functionalised derivatives of PTCDI. Alternative structures produced by altering the shape of the molecular 'building blocks' are also discussed. The URV-ESD technique is demonstrated here to be compatible with the deposition of the fullerene C60,the single molecule magnet Mn12012(02CCR3h6(H20)4 (Mn12(acetate)16), and porphyrin based oligomers (P4 and P6) and polymers (Pn). The URV-ESD of C60on the clean AU(ll1) surface, and on a surface prepatterned with a PTCDI/melamine network, results in similar structures to those previously observed to be produced by sublimation. Mn12(acetate)16 and the porphyrin oligomers and polymers represent complex molecules which are thermally labile and possess, respectively, novel magnetic and electronic properties. Mn12(acetate) 16is observed to form filamentary aggregates due to the anisotropic nature of the molecule-molecule and molecule-substrate interactions, while P4, P6 and Pn form highly ordered close-packed domains driven by the interdigitation of the alkyl chains attached to the porphyrin cores. The findings presented within this thesis demonstrate that self-assembled molecular structures can be understood in terms of intermolecular interactions, and that for systems containing complex molecules the molecule-molecule interaction potential can lead to the formation of novel structures.
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Al-Edhari, Ali Jaber. « Complex organic molecules in solar-type star forming regions ». Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY048/document.
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Le but de la présente thèse est l'étude de la compléxité moléculaire dans les régions de formation stellaires. Cette thèse s'axe sur deux classes de molécule aux caractéristiques prébiotiques : les molécules organiques complexes et les cyanopolyynes.Dans ce contexte, j'ai analysé des données d'un seul échantillon de relevés spec- traux en exploitant des codes de transfert radiatif à l'équilibre thermodynamique local (LTE) et/ou non-LTE pour deux sources : une proto-étoile de type solaire dans un environnement calme (IRAS 16293-2422) et un proto-ama constitué de proto-étoile de type solaire (OMC2-FIR4).L'objectif est de trouver des similar- ités et des différences entre ces deux cas.J'ai utilisé des données issu de deux relevés spectraux : TIMASSS (The IRAS16293-2422 Millimeter And Submilimeter Spectral Survey) réalisés en 2011 (Caux et al. 2011), et ASAI(Astrochemical Surveys At IRAM) réalisés pen- dant la période 2013-2015 (eg Lopez-Sepulcre et al.2015). J'ai extrais les lignes (identification et intensité intégrée) en utilisant le paquet disponible publique- ment : CASSIS (Centre d'Analyse Scientifique de Spectres Infrarouges et Sub- millimetrique). Pour finir, j'ai utilisé le paquet GRAPES (GRenoble Analysis of Protostellar Envelope Spectral) afin de modéliser la distribution spectrale énergétique de ligne (SLED) des molécules détectées, mais aussi afin d'estimer leurs abondances à travers l'envelope de IRAS16293 et du coeur chaud OMC2- FIR4.Les principaux résultats de la thèse sont :1. Le premier recensement complet des molecules organiques complexes (COMs) dans IRAS162932. La première détéction de COMs dans l'enveloppe froide d'une proto-étoile de type solaire (IRAS16293-2422) supportant l'idée qu'un méchanisme de formation, relativement efficace pour les COMs détectées, doit exister en phase gazeuse froide.3. La découverte d'une fine corrélation entre le diméthyle-éther (DME) et le méthyle-formate (MF) suggère une relation mère fille entre ces deux espèces.4. La detection de formamide, espèce avec un très fort potentiel prébiotique, dans plusieurs protoétoiles incluant IRAS16293-2422 et OMC2-FIR4.5. Le recensement complet des cyanopolyynes dans IRAS16293 et OMC2- FIR4 avec la détection de HC3N, HC5N, DC3N et pour OMC2-FIR4: le C13 isotopologue du HC3N cyanopolyynes.Ces résultats sont le sujet principal de deux publications (Jaber et al.2014, ApJ; Lopez-Sepulcre, Jaber et al.2015,MNRAS), un article accepté (Jaber et al., A & A) et un article à soumettre (Jaber et al. A & A)The present PhD thesis goal is the study of the molecular complexity in solar type star forming regions. It specifically focuses on two classes of molecules with a pre-biotic value, the complex organic molecules and the cyanopolyynes.At this scope, I analyzed data from single-dish spectral surveys by means of non-LTE or/and non-LTE radiative transfer codes in two sources, a solar type protostar in an isolated and quiet environment (IRAS16293-2422) and a proto-cluster of solar type protostars (OMC2-FIR4). The goal is to find similarities and differences between these two cases.I used data from two spectra surveys: TIMASSS (The IRAS16293-2422 Millimeter And Submillimeter Spectral Survey), which has been carried out in 2011 (Caux et al. 2011), and ASAI (Astrochemical Surveys At IRAM), which has been carried out in 2013-2015 (e.g. Lopez-Sepulcre et al. 2015).I extracted the lines (identification and integrated intensity) by means of the publicly available package CASSIS (Centre dAnalyse Scientifique de Spectres Infrarouges et Submillimtriques).Finally, I used the package GRAPES (GRenoble Analysis of Protostellar Envelope Spectra) to model the Spectral Line Energy Distribution (SLED) of the detected molecules, and to estimate their abundance across the envelope and hot corino of IRAS16293-2422 and OMC2-FIR4, respectively.The major results of the thesis are:1) The first full census of complex organic molecules (COMs) in IRAS16293-2422;2) The first detection of COMs in the cold envelope of a solar type protostar (IRAS16293-2422), supporting the idea that a relatively efficient formation mechanism for the detected COMs must exist in the cold gas phase;3) The discovery of a tight correlation between the dimethyl ether (DME) and methyl format (MF), suggesting a mother-daughter relationship;4) The detection of formamide, a species with a very high pre-biotic value, in several protostars, included IRAS16293-2422 and OMC2-FIR4;5) The full census of the cyanopolyynes in IRAS16293-2422 and OMC2-FIR4, with the detection of HC3N and HC5N, DC3N and, for OMC2-FIR4, the 13C isotopologue of HC3N cyanopolyynes.These results are the focus of two published articles (Jaber et al. 2014, ApJ; Lopez-Sepulcre, Jaber et al. 2015, MNRAS), one accepted article (Jaber et al., A&A) and a final article to be submitted (Jaber et al., A&A)
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Sadownik, Jan. « Evolving complex systems from simple molecules ». Thesis, St Andrews, 2009. http://hdl.handle.net/10023/857.
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Silva, Bermudez Phaedra Suriel. « Adsorption of complex organic molecules on metal single crystal surfaces ». Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426136.
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Clay, Matthew D. « Synthetic approaches to complex organic molecules : Desogestrel, acetylenic allenophanes, and Buckminsterfullerene ». Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/29344.
Texte intégralRésumé :
This thesis is composed of three sections and describes our work towards the synthesis of three molecules: Desogestrel, the first acetylenic allenophane, and Buckminsterfullerene.
Section A details a tether-controlled diene-transmissive intramolecular Diels-Alder reaction approach to the oral contraceptive progestin Desogestrel. Using our indium-mediated gamma-pentadienylation chemistry as a key step, we synthesized tetraenes 92 and 68. Unfortunately, the intramolecular Diels-Alder reaction of these tetraenes resulted in formation of three isomers, bicyclo[4.3.0]nonenes 96 and 97, and the unusual bicyclo[3.3.1]nonene 99. Attempts to improve the selectivity were unsuccessful and precluded further pursuit of the synthesis.
Section B of this thesis describes our design and asymmetric synthesis of the first acetylenic allenophane (308). This molecule represented a new class of cyclophane, and illustrative of the current interest in this type of molecule, several additional examples have since been reported, as well as an independent highlight in Angewandte Chemie. To complete our asymmetric synthesis, we developed a novel method of synthesizing tertiary propargyl alcohols (e.g., 299) in very good yield and enantioselectivity using a Sharpless asymmetric epoxidation as a key step. In contrast to the few procedures available for the asymmetric synthesis of tertiary propargyl alcohols, our protocol could be completed in roughly half the time, did not require the rigorous exclusion of oxygen or moisture, and did not require particularly specialized equipment.
Section C describes our work towards a controlled laboratory synthesis of Buckminsterfullerene (C60) using hexakis[(Z)-enynyl]benzenes. We have developed several approaches to these molecules using trisubstituted benzene test substrates and have used these methods to construct hexasubstituted benzenes 417 and 418 from bromoaldehyde 399 . We are presently attempting to convert 418 to our cyclophane precursor to C60.
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Vazart, Fanny. « Gas-phase formation of Complex Organic Models molecules in interstellar medium : computational investigations ». Doctoral thesis, Scuola Normale Superiore, 2017. http://hdl.handle.net/11384/85813.
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[excerpt form the abstract:] In the field of astro- and prebiotic chemistry, the building blocks of life, which are molecules composed of more than 6 atoms, are called Complex Organic Molecules (COMs). Their appearances on the early inorganic Earth is therefore one of the major issues faced by researchers interested in the origin of life. In this thesis, split into three parts, the main purpose is to show how different COMs are formed in interstellar medium (ISM), using computational chemistry.
The first part focuses mainly on preliminary studies aiming at evaluating the appropriate level of theory to use to perform studies of formation reactions. First, a comprehensive benchmark of C≡N stretching vibrations computed at harmonic and anharmonic levels is reported with the goal of proposing and validating a reliable computational strategy to get accurate results for this puzzling vibrational mode, involved in biological molcules, without any ad hoc scaling factor.
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Repiscak, Peter. « Computational chemistry for complex systems : open-shell molecules to conjugated organic materials ». Thesis, Heriot-Watt University, 2017. http://hdl.handle.net/10399/3348.
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This thesis focuses on two different, but equally challenging, areas of computational chemistry: transition metal organic molecule interactions and parameterisation of organic conjugated polymers for molecular dynamics simulations. The metal-binding properties are important for understanding of biomolecular action of type 2 diabetes drug and development of novel protocols for redox calculations of copper systems. In this area the challenge is mainly related to the complex electronic structure of the open-shell transition metals. The main challenges for the parameterisation of conjugated polymers are due to the size of the studied systems, their conjugated nature and inclusion of environment. Metal-binding properties as well as electronic structures of copper complexes of type 2 diabetes drug metformin (Metf) and other similar, but often inactive, compounds were examined using DFT method. It was found that for neutral compounds it is not possible to explain the differences in their biological effects solely by examining the copper-binding properties. Further, the proposed mechanism potentially explaining the difference in the biomolecular mode of action involves a possible deprotonation of biguanide and Metf compounds under higher mitochondrial pH which would lead to formation of more stable copper complexes and potentially affecting the mitochondrial copper homeostasis. In addition, redox properties of copper-biguanide complexes could interfere with the sensitive redox chemistry or interact with important metalloproteins in the mitochondria. Understanding the copper-binding properties is also important for a systematic development and testing of computational protocols for calculations of reduction potentials of copper complexes. Copper macrocyclic complexes previously used as model systems for redox-active metalloenzymes and for which experimentally determined redox potentials are available were used as model systems. First adequacy of using single reference methods such as DFT was examined for these systems and then various DFT functionals and basis sets were tested in order to develop accurate redox potential protocol. It was shown that good relative cor-relations were obtained for several functionals while the best absolute agreement was obtained with either the M06/cc-pVTZ functional with the SMD or either M06L or TPSSTPSS functional with cc-pVTZ basis set and the PCM solvation model. Organic conjugated polymers have a great potential due to their application in organic optoelectronics. Various wavefunction and DFT methods are utilized in order to systematically develop parameterisation scheme that can be used to derive selected force-field parameters such as torsional potentials between monomer units that are critical for these systems and partial charges. Moreover, critical points of such a parameterisation are addressed in order to obtain accurate MD simulations that could provide valuable insight into material morphology and conformation that affect their optical properties and conductivity. It was shown that a two step approach of geometry optimisation with CAM-B3LYP/631G* and single point (SP) energy scan with CAM-B3LYP/cc-pVTZ is able to yield accurate dihedral potentials in agreement with the potentials calculated using higher level methods such as MP2 and CBS limit CCSD(T). Further, investigating partial charge distribution for increasing backbone length of fluorene and thiophene it has been found that it is possible to obtain a three residue model of converged charge distributions using the RESP scheme. The three partial charge residues can be then used to build and simulate much longer polymers without the need to re-parametrize charge distributions. In the case of side-chains, it was found that it is not possible to obtain converged charge sets for sidechain lengths of up to 10 carbons due to the strong asymmetry between the side-chain ends. Initial validation of derived force-field parameters performed by simulations of 32mers of fluorene with octyl side-chains (PF8) and thiophene with hexyl side-chains (P3HT) in chloroform and calculation of persistence lengths and end-to-end lengths showed close correspondence to experimentally obtained values.
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Halfen, DeWayne Terrence. « Studies in Laboratory Spectroscopy and Radio Astronomy : From Simple Hydrides to Complex Organic Molecules ». Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/195962.
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There are two main objectives for this thesis. First, laboratory rotational spectra of metal-containing molecules were measured using the millimeter-wave spectrometers of the Ziurys group. Second, radio astronomical observations were performed on a number of the molecules measured in the laboratory, along with several organic species. The laboratory work is essential to the discovery of new molecules in the interstellar medium, and the understanding of the chemical composition of the universe. Identification of these species can only occur after their pure rotational spectra have been measured. Therefore, an investigation of the rotational spectra of several classes of molecules was performed including metal-bearing hydrides, chlorides, carbon-containing species, and molecular ions. The experimental measurements were aided by necessary improvements in the operation of the spectrometers. Many of these species had not been observed by any spectroscopic technique, including CaC, CuCH₃, FeCO⁺ and VCl⁺. Several of these molecules exhibited unusual interactions that complicated the analysis of their spectra, such as VCl, TiCl⁺, VCl⁺, and FeCO⁺. Synthesis of these species required exotic production techniques, including the use of Broida ovens and AC and DC discharges. Astronomical observations of several of the molecules studied in the laboratory were conducted, and upper limits to the abundances obtained. Additional searches for more of the species studied are planned. A region in the Galactic center with a complex chemical composition called Sgr B2(N) was recognized through observations of N₂O. Several organic species were then searched for in this source. The detection of the simple sugar glycolaldehyde was confirmed by observing all of the favorable transitions of this molecule in Sgr B2(N). A standard set of criteria for identifying complex organic molecules was drawn up as a result of this study. This investigation led to an attempt to confirm a larger sugar, dihydroxyacetone. Unfortunately the detection of this species was proven false, and a limit could be placed on the chemical complexity of this source.
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Rahnejat, K. A. « Capturing complex reaction pathways step by step : organic molecules on the Si(001) surface ». Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1473368/.
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Experts expect that inherent limitations in semiconductor electronics will become apparent within the next couple of decades. Consequently, the construction of novel electronic-devices that surpass existing technologies in both miniaturisation and intrinsic functionality is becoming increasingly important. The assembly of nanoscale circuitries comprised of individual, synthetically-tailored molecules designed to substitute conventional electronic-components is a popular approach to tackling this challenge. The incorporation of functional molecules with existing silicon-based electronics is the most credible route towards realising this goal in the near-future. To this end, we present a scanning tunnelling microscopy (STM) study of acetophenone—an archetypal, small, aromatic molecule—adsorbed onto the Si(001) surface. An elevated imaging bias is used to induce sequential structural-transitions in hundreds of adsorbates simultaneously. Specifically developed analytical-software was used to catalogue and analyse the transition sequences that were recorded. These transitions described long, complex surface-bound reaction-pathways in a step-by-step manner. Density functional theory (DFT) analysis reveals that acetophenone adsorbates adopt a remarkable 24 distinct adsorbate structures. Moreover, the captured reaction-pathways are up to six discreet steps in length and belong to one of three separate branches determined upon adsorption. These transitions are governed by predictable pivoting motions about a strong O–Si bond formed with the substrate. Our fundamental studies have informed the direct manipulation of individual adsorbates using precisely targeted voltage-pulses affording the control of specific transitions. In addition, we explore changes in the adsorption behaviour of these molecules after minor chemical modification through substitution of function groups. Finally, we construct and study 2D systems of overlapping wavefunctions by manufacturing dangling bonds (DB) on Si(001):H.
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Kong, Caleb J. « Engineering High Reaction Economy or, An Intensification/Scoring Program for the Preparation of Simple and Complex Molecules ». VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6023.
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Success of newly discovered chemistry in academia is often scored in terms of its novelty and level of scholarship. In industrial settings, cost, safety and quality are often times the ruler by which new processes are measured. Our group has identified that there is a gap between these two measures of success and has sought to develop principles in order formalize an approach to synthetic strategy and developing ready-to-implement manufacturing processes for molecules, simple and complex.
Some of these principles include (1) the development and application of new chemical methods and reactor technologies (2) recognition of globally amenable chemical environments for each chemical step to consolidate unit operations and obviate the need for purification (3) vertical integration of starting materials to generate complexity from the most elementary building blocks in a chemical supply space and (4) the development of new materials that allow for recovery and reuse. These principles are iteratively scored and redeveloped through various metrics that our group has identified as effective tools in maximizing efficiency such as cost of goods (CoG), process mass intensity (PMI) and volume-time output (VTO). The intended benefits of this approach is that these processes become not only cost effective but sustainable and impactful in the manufacturing landscape and increase access of these products to consumers.
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Dickson, Nicole Marie. « Exploration of the Excited States of Organic Molecules and Metal Complexes Using Ultrafast Laser Spectroscopy ». The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306872674.
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Bellavance, Gabriel. « Part A : Development of a Modular Synthetic Approach to Polycyclic Polyprenylated Acylphlorogluginols : Total Synthesis of Papuaforin A, B, C, Hyperforin and Formal Synthesis of Nemorosone. Part B : Studies Toward the Synthesis of Ginkgolides ». Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34630.
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Polycyclic Polyprenylated Acylphloroglucinols (PPAPs) are a vast family of natural products, which includes more than 200 members. They contain a stunningly complex molecular architecture which in most cases includes a bicyclo[3.3.1]nonane core. PPAPs have been of interest to the scientific community for their intricate structure, their powerful aid in treating many ailments and large portfolio of biological activities. More particularly, they have been of synthetic interest since 1999 with the first report of an approach to these complicated cores by Nicolaou. Herein, we present the first total synthesis of papuaforin A, papuaforin B, papuaforin C, hyperforin and the formal synthesis of nemorosone following a report by Simpkins and co-workers. We relied on a gold(I)-catalyzed carbocyclization for the construction of the core of this family of natural products. Ginkgolides are isolated from the ginko tree, Ginkgo biloba, a living fossil with records of its existence dating back 280 million years. For centuries, the plant and its extracts have been used extensively for their beneficial properties, especially in China, Japan and India. For example, extract Egb761, one of the most potent fraction, generates over $500 million a year alone. The ginkgolides possess a truly unique compact diterpene framework of six 5-membered rings with a high content oxygen. Eleven oxygens can be found in ginkgolide C for a core containing only 23 carbons. The ginkgolides also include a very unique feature: a tert-butyl group located on the most convoluted ring system: the B ring. Few groups have found success in limning a synthetic route to ginkgolides. Corey’s group was the first to achieve the total synthesis of ginkgolide B in 1987. He was also able to complete ginkgolide A a year later. Crimmins and co-workers also achieved the total synthesis of ginkgolide B a decade later in 1999. Herein, we present our new approach toward ginkgolides through a newly developed methodology for the α-allylation of ketones and the creation of highly hindered contiguous quaternary centers. The synthesis is still at an early stage but a synthetic pathway giving access to the ring B with all the key moieties has been extensively investigated.
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Alnagi, Omar. « Reaction de la trimethylphosphine sur les sels de cobalt (ii) : synthese des complexes pentacoordonnes cox ::(2)(pme ::(3)) ::(3) (x=c1**(-), br**(-), i**(-), ncs**(-), no ::(2)**(-)), reactivite vis-a-vis de petites molecules co, no et o ::(2) ». Toulouse 3, 1987. http://www.theses.fr/1987TOU30048.
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Synthese et etude physicochimique des complexes. Reactivite. Etude cristallographique de la structure indiquant une geometrie de bipyramide trigonale deformee quand x**(-)=cl**(-),br**(-),i**(-),ncs**(-) et une geometrie de pyramide a base carree pour x=no::(2)**(-). Etude des substitutions par co,no et o::(2)
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Jonušas, Mindaugas. « Study of photo-induced and radical reactions between CH4 and NH3 : astrochemical applications ». Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS048/document.
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L'eau joue un rôle fondamental dans la photochimie du milieu interstellaire (MIS), à travers la formation d'espèces très réactives comme OH. Les radicaux OH peuvent par la suite interagir avec d'autres molécules hydrogénées pour reformer H2O par abstraction d'hydrogène: R-H + OH → R* + H2O. Dans le cadre de ce travail de thèse, nous avons étudié l'influence des photons VUV sur des analogues de glace interstellaire. Nous montrons que l'incorporation d'une petite quantité d'eau dans NH3 et CH4 glaces augmente considérablement la formation de radicaux réactifs comme NH2 et CH3 pendant le processus de photolyse et que le chauffage des glaces binaires irradiées telles que NH3-H2O et CH4-H2O conduit à la formation de NH2OH et d'espèces alcooliques plus complexes comme le propanol et le métoxyméthanol. Nous avons également entamé d'autres études en parallèle sur le l'évolution thermique des glaces de NH2OH d'une part et la formation de propanol par voies énergétiques (irradiation VUV) et non énergétique (réaction d'addition H) d'autre part afin de tenter d'expliquer la non-détection des ces espèces organiques dans le milieu interstellaire. L'étude des glaces mixtes irradiées NH3-CH4-H2O a montré la formation à basse température d'espèces plus exotiques en combinant les spectrométries IR et de masse. Nous avons réussi à identifier des composés organiques très complexes déjà détectés ou activement recherchés dans le MISWater plays a fundamental role in the photochemistry of the interstellar medium (ISM), through OH radical formation. OH radicals can interact with other H-containing species to form H2O through a hydrogen abstraction reaction: R-H + OH → R* + H2O. In this work, we have investigated the VUV processing on different interstellar ice analogs. We show that the incorporation of small amount of water in NH3 and CH4 ices greatly increases the formation of reactive NH2 and CH3 radicals during the photolysis processing. Thermal treatments of irradiated NH3-H2O and CH4-H2O ices lead to the formation of NH2OH and larger alcoholic species such as propanol and metoxymethanol. Further studies of thermal processing of NH2OH ice and formation of propanol through energetic (VUV irradiation) and non-energetic (surface H-addition reaction) processing were carried out in the context of this thesis in order to try explaining their non-detection in the interstellar medium. The study of the irradiated mixed NH3-CH4-H2O ices showed the formation of more exotic species by combining the IR and mass spectrometries. We managed to identify very large complex organic compounds already detected or tensively sought in the ISM
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Lahoud, Marcelo Galindo [UNESP]. « Síntese e investigação da potencialidade de aplicação como material molecular de espécies discretas e Metal Organic Frameworks (MOFs) baseados em íons terras raras ». Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/143479.
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Este trabalho é dividido em duas partes, na primeira parte foi caracterizado o complexo [Ln(keto)3(H2O)] (Ln = Gd, Eu) por espectroscopia vibracional no infravermelho, analise elementar e otimização da geometria por método DFT. Mas o foco central foram os estudos das propriedades luminescente no intervalo de 12 – 300 K. O espectro de emissão do [Eu(keto)3(H2O)] revela uma forte dependência com a temperatura, bem ilustrada pelo não usual deslocamento amplo para o azul de (17 cm1) da transição 5D07F0 quando a temperatura é elevada de 12 a 300 K. A diferença aritmética entre os espectros de absorção do [Eu(keto)3(H2O)] com o do [Gd(keto)3(H2O)] indicou a presença de uma banda de transferência de carga do ligante para o metal (LMCT) (320-370 nm). A partir da fosforescência do [Gd(keto)3(H2O)] a energia dos estados de tripleto relacionada ao Keto foi determinada mostrando uma grande sobreposição com os níveis intra-4f6 e um forte acoplamento elétron-fônon. A alta ressonância entre o nível LMCT e estados tripletos e os níveis do Eu3+ leva a uma forte dependência do valor do tempo de vida da 5D0, típico da presença de processos de transferência de energia operativos. A segunda parte desse trabalho compreendeu na síntese, caracterização e estudos das propriedades luminescente e magnéticas de uma MOF inédito de formula [Eu2(Btec)1,5(H2O)]n. A MOF foi sintetizada por via hidrotermal e caracterizado por DRX de monocristal e pó, espectroscopia vibracional no infravermelho, reflectância difusa, analise elementar, analise térmica, microscopia eletrônica de varredura e fisissorção de N2. O composto apresentou boa estabilidade térmica no entanto mostrou-se ter baixa porosidade. A MOF apresentou emissão na região do vermelho com elevado rendimento quântico de emissão, mostrando que o ligante é um bom sensibilizador nesse sistema. As emissões dos íons Eu3+ mostraram-se ser uma sonda espectroscópica, contribuindo na elucidação da estrutura. Foi observado uma dependência térmica em relação à intensidade das transições originárias do nível 7F1, em especial a transição 7F15D1. Além disso, as transições intraconfiguracionais 4f-4f mostram ter uma boa fotoestabilidade. Resultados de susceptibilidade magnética mostram íons Eu3+ magneticamente afastados e portanto os torna uma fraca probe estrutural.
This work is divided into two parts, the first part was characterized the complex [Ln(keto)3(H2O)] (Ln = Gd, Eu) by infrared spectroscopy, elemental analysis and geometry optimization by DFT method. But the central focus was the study of luminescent properties in the 12-300 K interval. The emission spectra of [Eu(keto)3(H2O)] reveal a strong dependence with the temperature, well-illustrated by an unusual large blue-shift (17 cm1) of the 5D07F0 transition as the temperature is raised from 12 to 300 K. The arithmetic difference between the absorption spectrum of [Eu(keto)3(H2O)] with that of [Gd(keto)3(H2O)] pointed out the presence of a ligand-to-metal charge transfer (LMCT) band (320-370 nm). From the [Gd(keto)3(H2O)] phosphorescence the energy of the keto-related triplet states was determined showing a large overlap with the intra-4f 6 levels and a strong electron-phonon coupling. The high-resonance between the LMCT and triplet states and the Eu3+ levels leads to a strong dependence of the 5D0 lifetime value, typical of the presence of operative energy transfer processes. The second part of this work included in the synthesis, characterization and study of luminescence and magnetic properties of a novel MOF formula [Eu2(Btec)1,5(H2O)]n. The MOF was synthesized by way hydrothermal and characterized by XRD of single crystal and powder, infrared spectroscopy, diffuse reflectance, elemental analysis, thermal analysis, scanning electron microscopy and N2 physisorption. Compound demonstrated good thermal stability however proved to have low porosity. MOF showed emission in the red region with a high emission quantum yield, showing that the ligand is a good sensitizer in the system. The emission of Eu3+ ions proved to be a spectroscopic probe, contributing to the elucidation of the structure. A thermal dependence was observed in relation to the intensity of originating 7F1 level transitions, in particular the 7F15D1 transition. Furthermore, the 4f-4f transitions intraconfigurational shown to have a good photostability. Magnetic susceptibility results show Eu3+ ions separated magnetically and thus makes a weak probe structure.
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Hartstock, Frederick W. « Activation of organic molecules by transition metal complexes ». Thesis, University of Ottawa (Canada), 1987. http://hdl.handle.net/10393/5306.
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Galzerano, Patrizia <1982>. « New organocatalytic asymmetric strategies : simply catalysts for complex molecules ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2960/1/Galzerano_Patrizia_tesi.pdf.
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Galzerano, Patrizia <1982>. « New organocatalytic asymmetric strategies : simply catalysts for complex molecules ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2960/.
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Robertson, Craig Collumbine. « Building complex systems based on simple molecular architectures ». Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2573.
Texte intégralRésumé :
Over the past twenty years molecules capable of templating their own synthesis, so called self–replicating molecules have gained prominence in the literature. We show herein that mixing the reagents for replicating molecules can produce a network of self–replicators which coexist and that the networks can be instructed by the addition of preformed template upon initiation of the reaction. Whilst self–replicating molecules offer the simplest form of replication, nature has evolved to utilise not minimal self–replication but reciprocal replication where one strand templates the formation of not an identical copy of itself but a reciprocal strand. Efforts thus far at producing a synthetic reciprocal replicating system are discussed and an alternative strategy to address the problems encountered is proposed and successfully implemented. The kinetic behaviour of a self–replicating reaction bears two distinctive time periods. Upon initiation, the reaction proceeds slowly as no template exists to catalyse the reaction. Upon production of the template, the reaction proceeds more rapidly via template direction. During this slow reaction period, the system is prone to mistakes as the reaction is slow and unselective. The creation of an [A•B] binary complex through non–covalent recognition of reagents allows for the reaction to proceed at an accelerated rate upon initiation however products of such a reaction are usually catalytically inert and do not promote further template directed reaction. A strategy to combine the desired behaviour of an [A•B] binary complex with the further template directed autocatalytic self–replicating reaction is described and implemented. Supramolecular polymers consist of repeating monomers which are held together by non–covalent interactions. The strong association of a self–replicating template dimer is comparable to that of supramolecular polymers reported thus far in the literature which are produced by cumbersome standard linear synthetic procedures. Herein the application of self–replication to the field of supramolecular polymer synthesis is discussed. As the autocatalytic reaction to produce the template monomers occurs under the same conditions as required to allow polymerisation to proceed, the polymer is able to spontaneously form in situ by self–replicating supramolecular polymerisation.
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Kettley, J. C. « Van der Waals complexes of large aromatic molecules ». Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371128.
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Nordlund, Michael. « Carbon Nanostructures – from Molecules to Functionalised Materials : Fullerene-Ferrocene Oligomers, Graphene Modification and Deposition ». Doctoral thesis, Uppsala universitet, Organisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-327189.
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The work described in this thesis concerns development, synthesis and characterisation of new molecular compounds and materials based on the carbon allotropes fullerene (C60) and graphene. A stepwise strategy to a symmetric ferrocene-linked dumbbell of fulleropyrrolidines was developed. The versatility of this approach was demonstrated in the synthesis of a non-symmetric fulleropyrrolidine-ferrocene-tryptophan triad. A new tethered bis-aldehyde, capable of regiospecific bis-pyrrolidination of a C60-fullerene in predominantly trans fashion, was designed, synthesised and reacted with glycine and C60 to yield the desired N-unfunctionalised bis(pyrrolidine)fullerene. A catenane dimer composed of two bis(pyrrolidine)fullerenes was obtained as a minor co-product. From the synthesis of the N-methyl analogue, the catenane dimer could be separated from the monomeric main product and fully characterised by NMR spectroscopy. Working towards organometallic fullerene-based molecular wires, the N-unfunctionalised bis(pyrrolidine)fullerene was coupled to an activated carboxyferrocene-fullerene fragment by amide links to yield a ferrocene-linked fullerene trimer, as indicated by mass spectrometry from reactions carried out at small scale A small library of conjugated diarylacetylene linkers, to be coupled to C60 via metal-mediated hydroarylation, was developed. Selected linker precursors were prepared and characterised, and the hydroarylation has been adapted using simple arylboronic acids. Few-layer graphene was prepared and dip-deposited from suspension onto a piezoelectric polymer substrate. Spontaneous side-selective deposition was observed and, from the perspective of non-covalent interaction, rationalised as being driven by the inbuilt polarization of the polymer. Aiming for selectively edge-oxidized graphene, a number of graphitic materials were treated with a combination of ozone and hydrogen peroxide under sonication. This mild, metal-free procedure led to edge-oxidation and exfoliation with very simple isolation of clean materials indicated by microscopy, spectroscopy, and thermogravimetric analysis.
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Tahiri, Mohamed. « Phtalocyanines de fer(i) et de fer(0) : synthese, structure et reactivite ». Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13043.
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Synthese et caracterisation d'une serie de complexes monoreduits de phtalocyanine de fer de type (fe pc r::(8))**(-) ou r=och::(3), ch::(3), h, cl et cn. On donne les structures par rx de composes monoanioniques et dianionique fe pc**(-) et fe pc**(2-). Proprietes chimiques de fe pc**(2-). De tels especes peuvent etre des modeles d'intermediaires formes dans la reaction de la phenylhydrazine sur la metmyoglobine ou dans le metabolisme de substrats suicides par cytochrome p450
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Delavaux, Béatrice. « Complexes heterobimetalliques hydrures (ru-m) (m=rh,ir,cu) a ligands bisdiphenylphosphinomethane : synthese et reactivite ». Toulouse 3, 1986. http://www.theses.fr/1986TOU30078.
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Synthese de complexes hydruro a coordinat dppm : ph::(2) pch::(2) pph::(2). L'etude de la reactivite de certains complexes comme rurhh::(2)cl(cod) (dppm)::(2), conduit a la preparation de nouveaux hydrures dont on etudie les structures
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Cragg-Hine, Ian. « Early main group metal complexes of multi-functional organic molecules ». Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/271932.
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Yates, P. C. « Investigation of molecular structure of macrocyclic complexes ». Thesis, University of Reading, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373770.
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Higgins, Jessica Anne. « Organouranium complexes for the insertion and reduction of small molecules ». Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/53503/.
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This thesis explores the behaviour of U(III) and U(IV) organometallic complexes towards small molecules, with respect to both their reductive activity and insertion chemistry. A range of mixed-sandwich U(IV) organyl complexes of the form U(η-C8H6{1,4-SiiPr3}2)(η-C5Me5)(R) (= U(COTTIPS2Cp*(R), where R = CH3, CH2Ph, CH2TMS, CH{TMS}2) have been synthesised and the products of their reactions with CO2, CO, and H2 (κ2-carboxylates, η2-acyls, and a monomeric terminal hydride) have been characterised – all of which are formed under mild conditions (< 1 atm of gas, sub-ambient temperature). The hydride also inserts CO2 to yield a formate, U(COTTIPS2)Cp*(κ2-O2CH), which is the first example of its kind, and inserts CO to form cis-enediolate, {U(COTTIPS2)Cp*}2(μ-κ1:κ1-OCH=CHO). A rare primary amido, U(COTTIPS2)Cp*(NH2), and its CO2 insertion product, U(COTTIPS2)Cp*(κ2-O2CNH2), have also been characterised. The latter is the first crystallographically characterised U(IV) primary carbamate. Deprotonation of the parent amido yield an anionic U(IV) terminal primary imido, [U(COTTIPS2)Cp*(NH)][K(18-crown-6)]. U(III) and U(IV) complexes containing a dianionic diamidoamine ligand, [N{SiMe3}(CH2CH2N{SiMe3})2]2- (= N'N'2) have been synthesised. It has been found that the migration of a SiMe3 group along the ligand backbone occurs spontaneously when bound to uranium. Reduction of the U(IV) compound U(N'N'2)Cp*Cl with KC8 yields either the U(III) product, U(N'N'2)Cp*, or bridging arene products, {U(N'N'2)}2(μ-η6:η6-C6H5R) (where R = H, Me), depending on the reaction stoichiometry. Further reactivity of these diamidoamine complexes with small molecules is also discussed.
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Hu, Jin. « The binding and activation of small molecules by rhenium thiolato-complexes ». Thesis, University of Essex, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306071.
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Ball, S. C. « Studies on new mono- and di-lithiated complexes of organic molecules ». Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596320.
Texte intégralRésumé :
This thesis describes the syntheses and characterisations of new mono- and di-lithiated complexes of organic molecules of the general formula [(Rx-).xLi+].yL. The anion Rx- is either derived from a primary amine or is from a multifunctional organic molecule, containing one or more heteroatoms (usually N or S). The complexes have been prepared either by direct reaction of a simple amine with a metal source (solutions of nBuLi, tBuLi, LDA), or via a multi-stage reaction following an established synthetic organic protocol, attempt to isolate the lithiated intermediates at each stage. A variety of solvents, both hydrocarbon (toluene, hexane) and polar solvents (diethylether, THF), were used and all of the metallated complexes contain stoichiometric quantities of Lewis base donors, L (TMEDA, PMDETA, THF, Et2O). One mono-sodiated complex is also described. The work presented concentrates on the preparation and characterisation of new dilithiated complexes both in the solid state and in solution. The lithiated intermediates in many organic reactions provide a source of such dilithiated molecules. In general deprotonation of an organic acid, followed by insertion of a functional group (CS2, RCN) into the E-M bond (E=C, N; M=Li, Na) and in some cases further metallation, forms the basis of the reactions described. Chapter 1 provides a general introduction to the area of lithiated organics, with a brief review of X-ray structure analyses and solution studies on such complexes. In Chapter 2 the general experimental methods used to synthesise and characterise these complexes are described. Chapter 3 reports an investigation into an established synthetic protocol for the conversion of β-substituted N-containing heterocycles to their pyrrolo derivatives via metallation and nitrile insertion. Details of complexes 3-C5H4NCH=C(Ph)NHC(Ph)=NLi.PMDETA and 2,3-C5H4NCH=C(R)NX.xTHF ("problem") are provided where R=Ph or tBu and X=Li (L=THF) or X=H. The preparation and characterisation of the mono- and di-lithiated complexes of the related α-substituted pyridine derivatives are also described.
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Mitsutake, Ayori, et Yuko Okamoto. « Multidimensional generalized-ensemble algorithms for complex systems ». American Institite of Physics, 2009. http://hdl.handle.net/2237/12622.
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Senevirathna, Wasana. « Azadipyrromethene-based Metal Complexes as 3D Conjugated Electron Acceptors for Organic Solar Cells ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1402062085.
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Tkacheva, T. N., S. L. Yefimova, V. K. Klochkov, A. V. Sorokin et Yu V. Malyukin. « Spectroscopic Study of Cationic Carbocyanine Dye Binding to GdYVO4:Eu Nanoparticles ». Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35005.
Texte intégralRésumé :
The interaction of the inorganic nanoparticles (GdYVO4:Eu, d 2 nm) and organic carbocyanine dye
3,3’ -diethyloxa-carbocyanine iodide (DiOC2) has been studied spectrophotometrically. The formation of
complexes of dye molecules with spherical nanoparticles GdYVO4:Eu in aqueous solutions of cationic dye
DiOC2 was found. It is shown that nanoparticle GdYVO4:Eu can form a complex with 5-10 molecules of the
cationic dye DiOC2 which leads to the decrease in the intensity of the absorption and luminescence spectra
of the dye in aqueous solution.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35005
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Guérin, Frédéric. « Pyridine diamide complexes of early transition metals, activation of small organic molecules ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ27151.pdf.
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Jazzar, Rodolphe Fouad Rene. « Small molecule activation by ruthenium phosphine and N-heterocyclic carbene complexes ». Thesis, University of Bath, 2003. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275790.
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Meyer, Jörg, Anja Wadewitz, Lokamani, Cormac Toher, Roland Gresser, Karl Leo, Moritz Riede, Francesca Moresco et Gianaurelio Cuniberti. « Molecules for organic electronics studied one by one ». Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-138788.
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The electronic and geometrical structure of single difluoro-bora-1,3,5,7-tetraphenyl-aza-dipyrromethene (aza-BODIPY) molecules adsorbed on the Au(111) surface is investigated by low temperature scanning tunneling microscopy and spectroscopy in conjunction with ab initio density functional theory simulations of the density of states and of the interaction with the substrate. Our DFT calculations indicate that the aza-BODIPY molecule forms a chemical bond with the Au(111) substrate, with distortion of the molecular geometry and significant charge transfer between the molecule and the substrate. Nevertheless, most likely due to the low corrugation of the Au(111) surface, diffusion of the molecule is observed for applied bias in excess of 1 VDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Meyer, Jörg, Anja Wadewitz, Lokamani, Cormac Toher, Roland Gresser, Karl Leo, Moritz Riede, Francesca Moresco et Gianaurelio Cuniberti. « Molecules for organic electronics studied one by one ». Royal Society of Chemistry, 2011. https://tud.qucosa.de/id/qucosa%3A27781.
Texte intégralRésumé :
The electronic and geometrical structure of single difluoro-bora-1,3,5,7-tetraphenyl-aza-dipyrromethene (aza-BODIPY) molecules adsorbed on the Au(111) surface is investigated by low temperature scanning tunneling microscopy and spectroscopy in conjunction with ab initio density functional theory simulations of the density of states and of the interaction with the substrate. Our DFT calculations indicate that the aza-BODIPY molecule forms a chemical bond with the Au(111) substrate, with distortion of the molecular geometry and significant charge transfer between the molecule and the substrate. Nevertheless, most likely due to the low corrugation of the Au(111) surface, diffusion of the molecule is observed for applied bias in excess of 1 V.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Bissonnette, Martine C. « Ion/radical and ion/molecule complexes and ion structure assignments in the gas phase ». Thesis, University of Ottawa (Canada), 1991. http://hdl.handle.net/10393/7731.
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The fragmentation mechanism of ionized neopentanol, (CH$\sb3$)$\sb3$CCH$\sb2$OH$\sp{+-}$, has been studied in great detail along with other C$\sb5$H$\sb $H$\sp{+-}$ isomers. The use of $\sp $C and D labelling was found an essential tool to establish the relation between the other species involved in the dissociation of neopentanol. The involvement of (CH$\sb3$)$\sb2$C$\sp{\cdot}$CH$\sb2\sp+$(O)HCH$\sb3$, (CH$\sb3$)$\sb3$C$\sp+$(O)HCH$\sb2$ and (CH$\sb3$)$\sb2$($\sp\cdot$CH$\sb2$)CCH$\sb2\sp+$OH$\sb2$ was essential to explain the H/D label exchange occurring upon fragmentation of neopentyl alcohol. An ion-dipole complex between methanol and ionized methyl propene is proposed as the final intermediate which leads directly to the products, methanol and ionized methyl propene. The results of the investigation of C$\sb7$H$\sb5\sp+$ ions from various precursor molecules are also described. The following compounds, which all produce C$\sb7$H$\sb5\sp+$ ions, were studied: benzyl acetate, benzyl formate, benzyl alcohol, 2-bromocyclopropabenzene, 1,6-heptadiyne and 1,5-decadiyne. According to the metastable ion (MI) mass spectra and the He collision induced dissociation (CID) of m/z 89 ions, it is suggested that four structures exist. (Abstract shortened by UMI.)
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Caulfield, Jason M. « Magnetic quantum oscillations in organic metals based on the molecule bis(ethylenedithio)tetrathiafulvalene ». Thesis, University of Oxford, 1994. http://ora.ox.ac.uk/objects/uuid:5fbf2599-96d8-4eac-b882-ac74213ac3a5.
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ET charge transfer salts (where ET is
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Magri, Andrea. « Multifunctional complexes for molecular devices ». Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAE036/document.
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Les semi-conducteurs organiques à base d’aluminium ont été systématiquement synthétisés et caractérisés par méthodes photo-physiques et électrochimiques. Une étude de leur relation structure-propriétés électroniques a été menée. Les orbitales frontières ont été comparées à celles obtenues par calcul. De nouvelles méthodes ont été utilisées permettant une description de la morphologie des SCOs et un calcul de mobilité des porteurs de charges associés. La mobilité des trous dans Al(Op)3 a été mesurée sur des transistors en film minces: 0.6-2.1×10−6cm2V−1s−1. Par des techniques de spectroscopie en photoémission, la surface de l’hybride Co/Al(Op)3 a été sondée, révélant deux états d’interfaces hybrides, où la polarisation de spin de HIS1 est 8% plus élevée comparée au cobalt nu, et 4% plus faible dans HIS2. Enfin, des aimant moléculaires à base de phénalényle ont été étudiés. [Dy(Op)2Cl(HOp)(EtOH)] présente notamment un gap énergétique de 43.8K et un temps de relaxation de 5x10-4 sAluminum-based organic semiconductors (OSCs) were systematically synthesized and studied by photophysical and electrochemical methods to identify a relationship between their chemical structure and electronic properties, using Alq3 as benchmark. Experimental HOMO and LUMO were compared to those computed. In addition, newly developed methods were implemented to generate morphologies and calculate charge carrier mobilities. The hole mobility of Al(Op)3 was measured in thin film transistors: 0.6-2.1×10−6 cm2V−1s−1. By photoemission spectroscopy techniques, the Co/Al(Op)3 hybrid interface was probed. Two hybrid interface states (HISs) were unraveled; the SP (spin polarization) of HIS1 is 8% higher than bare cobalt, whereas the SP of HIS2 is 4% lowered. At last, phenalenyl-based dysprosium SMMs (single-molecule magnet) were investigated. [Dy(Op)2Cl(HOp)(EtOH)] showed an energy gap of 43.8K and a quantum relaxation time of 5x10-4s
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Khan, Mustayeen Ahmed. « Stabilite, spectres electroniques et structures des halogenocuprates en milieu protique ». Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13059.
Texte intégralRésumé :
Etude des complexes de cu(ii) dans les solvants protiques l'eau, le methanol et l'acide acetique. On caracterise 4 complexes successsifs; calcul de leurs constantes de stabilite. Etude de l'effet du solvant sur les spectres electroniques
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Etienne, Michel. « Réactivité de complexes dinucléaires hydrure et alcénylidène ponte du fer vis-a-vis d'hydrocarbures cyanes insatures (mono et dicyanoacétylène, tétracyanoethylène) ». Brest, 1988. http://www.theses.fr/1988BRES2009.
Texte intégralRésumé :
Preparation de complexes avec des coordinats cyano-4 butadienyldene portants. On obtient egalement des complexes dinucleaires avec le tricyano-3,4,4 butadienylidene-1,3. Mecanisme ses reactions de migration de l'hydrogene allylique
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Ying, Tsang Min. « Multifunctional N,O-type carborane-based materials : from molecular complexes to three dimensional metal-organic frameworks ». Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/305240.
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1) Por un lado se describe la síntesis de derivados del orto-, meta- y/o para-carborano mono- and bis-funcionalizados con grupos alcohol metil piridinas, con énfasis en la naturaleza quiral de dichasmoléculas y las estructurassupramoleculares en el estadosólido. El análisis de las estructurasmoleculares y supramoleculares de los derivados monosubstituidos racémicos y enantioméricamente puros obtenidos se han comparado con derivados relacionados anteriormente publicados. Esto ha permitido encontrar una correlación entre los ángulos de torsión OCCN de las moléculas y quiralidad de las hélices supramoleculares que se observan en dichasestructuras. En el caso de los derivados bis-funcionalizados, los resultados muestran que las estructuras supramoleculares estándominadas por interacciones de hidrógeno OH…N y/o OH…O. El análisis de dichasestructuras ha revelado una posible preferencia por el autoensamblado homoquiral frente al heteroquiral.
2) Por otrolado se describe la química de coordinación de los derivados orto- y meta-carborano mono-funcionalizados con grupos alcohol metil piridinas. Así, se han preparado y caracterizado complejos dinucleares quirales de Fe(III) asimétricos. Se han estudiado propiedades magnéticas, quirópticas y en óptica no líneal. En este apartado se describe una sorprendentere solución expontánea por precipitación. El bloquefinaliza con los primerosejemplos de complejos de Cu(I) de los ligandos monosubstituidos, todo sellos luminiscentes en estadosólido.
3) En otra sección de la tesis se han recogidotodos los resultados referentes a la química de coordinación de los derivados orto- y meta-carborano bis-funcionalizados con grupos alcohol metil 2-piridina. Por un lado se describe la síntesis, caracterización y propiedades catalíticas de una serie de complejos NBN pincer de paladio. Por otro, se describen los primeros ejemplos de complejos dinucleares de Fe(III) con los ligandos bis-funcionalizados.
4) En el últimoapartado se describentodos los resultados encontrados en la química de coordinación de los derivados orto- y meta-carborano bis-funcionalizados con grupos alcohol metil 3- y 4-piridinas. La rica capacidad de coordinación de estos nuevosligandos bis-funcionalizados ha permitido preparar complejos moleculares de Pd, polímeros de coordinación de Zn y una novedos a familia de Metal Organic Frameworks (MOFs) en los que se combinan los ligandos bis-funcionalizados con acidos carboxílicosorgánicos y Zn o Co. En este último apartado se describen las propiedades que los ligandos bis-funcionalizados aportan a los MOFs, entre las que se encuentra una mayor estabilidad en agua.1) The first section describes the synthesis and characterization of the mono- and di-substituted carborane-based pyridylalcohol derivatives with ortho-, meta- and/or para-carborane, with emphasis onthe chiral nature and supramolecular structures of such molecules in the solid state.The molecular and supramolecular structures for the racemic and enantiopure monosubstituted derivatives have been compared with those previously reported. It has been found a possible correlation between the OCCN torsion angles of the molecules and the chirality of the supramolecular helices found in the structures. In the case of the di-substituted derivatives, it was found that the supramolecular structures are dominated by intermolecular OH…N and/or OH…O hydrogen bonds. The analysis of the structures revealed a preference for homochiral self-assembly over heterochiral. 2) Then it is described the coordination chemistry of monosubstituted methylalcohol pyridine ortho- and meta-carborane derivatives. Thus, chiral and unsymmetric Fe (III) complexes have been prepared and characterized. It has been studied their magnetic, chiroptical and non lineal optical properties. It is also described a surprising spontaneous resolution on precipitation. This part is then ended with the first examples of Cu (I) complexes incorporating the monosubstituted ligands and their luminescence properties in the solid state. 3) In the following section of the thesis it is summarized all results dealing with the coordination chemistry of disubstituted methylalcohol 2-pyridine ortho- and meta-carborane derivatives. On one hand it is described the synthesis, characterization and catalytic properties of a series of NBN palladium pincer complexes. On another hand, it is described the first examples of dinuclear Fe (III) complexes with such disubstituted ligands. 4) In the last part it is described all results found on the coordination chemistry of disubstituted ortho- and meta-carborane derivatives with 3- and 4-pyridyl alcohol groups. The rich coordination ability of these new di-substituted ligands has allowed the preparation of molecular Pd complexes, Zn coordination polymers and a novel family of Metal Organic Frameworks (MOFs). The latter being a combination of disubstituted ligands, organic polycarboxylic acids and Zn or Co. In this last part, it is described the properties that the disubstituted ligands transfer to the MOFs, such as for example, water stability.
42
Davesne, Vincent. « Organic spintronics : an investigation on spin-crossover complexes from isolated molecules to the device ». Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01062266.
Texte intégralRésumé :
We have studied by STM, SQUID, X-ray reflectivity, X-ray diffraction, optical absorption and XAS Fe(phen)2(NCS)2 and Fe{[3,5-dimethylpyrazolyl]3BH}2 samples deposited by thermal evaporation on Cu(100), Co(100) and SiO2 substrates, and compared with results on powder samples. We have confirmed the existence of the soft X-ray induced excited spin state trapping (SOXIESST), and investigated its properties, in particular dynamic aspects. The effect is sensitive to the intensity and the structure of the applied X-ray beam, and is non-resonant. We suggest that its efficiency is also governed by metal-ligand charge transfer states (MLCT). The study of single molecules has revealed that they could be switched by voltage pulses, and by this way building memristive devices, but only if the influence of the substrate is sufficiently reduced. We have then investigated thin films with the help from a simple thermodynamic model, and evidenced that the cooperativity was reduced and the transition temperature is modified (higher for Fe-phen, and lower for Fe-pyrz). Finally, we use these results to build multilayer vertical devices Au/Fe-phen/Au, and its electrical properties depends, according to our preliminary results, on the external stimuli (temperature, magnetic field). Notably, they present a "diode" effect at the spin transition.
43
Casati, Costanza <1984>. « Synthetic strategies of new molecular paramagnetic mechanically-interlocked complexes ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3778/1/Casati_Costanza_tesi.pdf.
Texte intégralRésumé :
Supramolecular chemistry is a multidisciplinary field which impinges on other disciplines, focusing
on the systems made up of a discrete number of assembled molecular subunits. The forces
responsible for the spatial organization are intermolecular reversible interactions.
The supramolecular architectures I was interested in are Rotaxanes, mechanically-interlocked
architectures consisting of a "dumbbell shaped molecule", threaded through a "macrocycle" where
the stoppers at the end of the dumbbell prevent disassociation of components and catenanes, two or
more interlocked macrocycles which cannot be separated without breaking the covalent bonds.
The aim is to introduce one or more paramagnetic units to use the ESR spectroscopy to investigate
complexation properties of these systems cause this technique works in the same time scale of
supramolecular assemblies.
Chapter 1 underlines the main concepts upon which supramolecular chemistry is based, clarifying
the nature of supramolecular interactions and the principles of host-guest chemistry.
In chapter 2 it is pointed out the use of ESR spectroscopy to investigate the properties of organic
non-covalent assemblies in liquid solution by spin labels and spin probes. The chapter 3 deals with
the synthesis of a new class of p-electron-deficient tetracationic cyclophane ring, carrying one or
two paramagnetic side-arms based on 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) moiety.
In the chapter 4, the Huisgen 1,3-dipolar cycloaddition is exploited to synthesize rotaxanes having
paramagnetic cyclodextrins as wheels.
In the chapter 5, the catalysis of Huisgen’s cycloaddition by CB[6] is exploited to synthesize
paramagnetic CB[6]-based [3]-rotaxanes.
In the chapter 6 I reported the first preliminary studies of Actinoid series as a new class of
templates in catenanes’ synthesis. Being f-block elements, so having the property of expanding the
valence state, they constitute promising candidates as chemical templates offering the possibility to
create a complex with coordination number beyond 6.
44
Casati, Costanza <1984>. « Synthetic strategies of new molecular paramagnetic mechanically-interlocked complexes ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3778/.
Texte intégralRésumé :
Supramolecular chemistry is a multidisciplinary field which impinges on other disciplines, focusing
on the systems made up of a discrete number of assembled molecular subunits. The forces
responsible for the spatial organization are intermolecular reversible interactions.
The supramolecular architectures I was interested in are Rotaxanes, mechanically-interlocked
architectures consisting of a "dumbbell shaped molecule", threaded through a "macrocycle" where
the stoppers at the end of the dumbbell prevent disassociation of components and catenanes, two or
more interlocked macrocycles which cannot be separated without breaking the covalent bonds.
The aim is to introduce one or more paramagnetic units to use the ESR spectroscopy to investigate
complexation properties of these systems cause this technique works in the same time scale of
supramolecular assemblies.
Chapter 1 underlines the main concepts upon which supramolecular chemistry is based, clarifying
the nature of supramolecular interactions and the principles of host-guest chemistry.
In chapter 2 it is pointed out the use of ESR spectroscopy to investigate the properties of organic
non-covalent assemblies in liquid solution by spin labels and spin probes. The chapter 3 deals with
the synthesis of a new class of p-electron-deficient tetracationic cyclophane ring, carrying one or
two paramagnetic side-arms based on 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) moiety.
In the chapter 4, the Huisgen 1,3-dipolar cycloaddition is exploited to synthesize rotaxanes having
paramagnetic cyclodextrins as wheels.
In the chapter 5, the catalysis of Huisgen’s cycloaddition by CB[6] is exploited to synthesize
paramagnetic CB[6]-based [3]-rotaxanes.
In the chapter 6 I reported the first preliminary studies of Actinoid series as a new class of
templates in catenanes’ synthesis. Being f-block elements, so having the property of expanding the
valence state, they constitute promising candidates as chemical templates offering the possibility to
create a complex with coordination number beyond 6.
45
Rhoad, Jonathan S. « DNA-binding carbohydrates for coordination to a photoactive dirhodium complex and molecular dynamics studies of methyl furanosides : evaluation of available force fields ». The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1101315894.
Texte intégral
46
Kahan, Rachel Jennifer. « Investigating the steric and electronic effects of low-valent uranium complexes on the activation of small molecules ». Thesis, University of Sussex, 2015. http://sro.sussex.ac.uk/id/eprint/54170/.
Texte intégralRésumé :
In the last decade substantial progress has been made in our understanding of uranium organometallic chemistry, specifically regarding the activation of small molecules by uranium(III) complexes. Research by Cloke and colleagues has employed dianionic eight- and monoanionic five-membered aromatic ligands around a uranium(III) centre to make mixed-sandwich systems, which have demonstrated novel reactivity with carbon monoxide and carbon dioxide. This thesis continues this work and furthers our understanding of the properties and reactivity of these complexes. The first part of this thesis describes the preparation of novel mixed-sandwich complexes incorporating the COT(SiiPr3)2 ligand and either a substituted cyclopentadienyl ring or a heterocyclic analogue. The steric parameters of these complexes have been quantitatively evaluated and provide insight into the molecular structures and reactivity observed. The electronic properties of the complexes have been investigated using cyclic voltammetry and complement results obtained by other researchers from the group. The second part of this thesis describes the reactivity of the novel mixed-sandwich complexes with small molecules. Whilst it was found the cyclopentadienyl complexes exhibit similar reactivity with carbon monoxide and carbon dioxide to previously reported complexes, the heterocyclic analogues provided a wealth of new reactivity, including facile cleavage of carbon monoxide at ambient temperatures, synthesis of an unusual phosphacarbonate fragment, and unprecedented synthesis of a 2,2'-bis(arsenine) species. The third part of this thesis explores the reactivity of potential precursors to uranium(II) metallocene complexes. Uranium complexes in this oxidation state have only recently been synthesised and the formation of a uranium(II) sandwich complex is desirable for its anticipated reactivity with small molecules. Reactivity studies include the attempted reduction of uranium(III) iodide precursors with potassium-based reducing agents and the synthesis of a novel uranium(II) tetraphenylborate complex.
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Ellis, Robert. « Investigation of cobalt complexes of Schiff's bases and dioximes - radical precursors and molecular recognition ». Thesis, University of Derby, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293297.
Texte intégral
48
Steen, Robert. « The Synthesis of Molecular Switches Based Upon Ru(II) Polypyridyl Architecture for Electronic Applications ». Licentiate thesis, Västerås : Department of Biology and Chemical Engineering, Mälardalen University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-356.
Texte intégral
49
Zhang, Hongtu. « Activation of Small Molecule and Organic Substrates by Tris(Phosphinoamide) Zr/Co Heterobimetallic Complexes ». The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1594900050962052.
Texte intégral
50
Miranda, Jussara Marques de. « Determinação de estruturas cristalinas por difração de raios-x : aplicação a um complexo de lantanídeo e a um composto orgânico natural ». Universidade de São Paulo, 1986. http://www.teses.usp.br/teses/disponiveis/54/54132/tde-18082014-114658/.
Texte intégralRésumé :
O primeiro capítulo desta dissertação é dedicado a uma revisão teórica da interação dos raios-X com cristais e métodos utilizados para a determinação de estruturas cristalinas. Nos capítulos seguintes, descreve-se os equipamentos experimentais utilizados e resolução de duas estruturas cristalinas cujos principais resultados são apresentados a seguir: Estrutura do complexo HO(ReO4)34 TDTD 3 H2O. Sistema cristalino; monoclínico; grupo espacial P21/c; a=17.955(3) Å b=17.100(6) Å c=12.570(3) Å β=92.48(2) ° V=3855(3) z=4; Dc = 2.720 g/cm3; (MoKα)= 0.71073 Å µ=114.08 cm-1. O índice de discordância final foi de R = 6.4% para 3050 reflexões com I >3σ(I). O cátion HO+3 é coordenado por oito átomos de oxigênio, que configuram um dodecaedro (simetrias D2d). Os poliedros de coordenação são ligados por grupos TDTD, dando origem a cadeias infinitas na direção a. Estrutura de Ormosalin - C14H16O6. Sistema cristalino: monoclínico, grupo espacial: P21/c; a=10.765(4) Å b=14.692(5) Å c=8.374(4); β=98.02(3)° V=1305(2) , z=4, Dc = 1.43 g/cm3, λ(MoKα)=0.71073 Å, ¿=0.07 mm-1; R=0.058 para 807 reflexões com estrutura conta com dois anéis de cinco membros em conformação torcida antissimétricaIn the first chapter of this work we review some theoretical aspects concerning the interaction of X-rays with crystals and the methods used to determine crystal structure. The following chapters describe the experimental equipments used and the determination of two crystalline structures. The main results obtained are now out11ned. The structure of the complex HO(ReO4)34 TDTD 3 H2O. Crystal system, monoclinic, space P21/c; a=17.955(3) Å b=17.100(6) Å c=12.570(3) Å β=92.48(2) ° V=3855(3) z=4; Dc = 2.720 g/cm3; (MoKα)= 0.71073 Å µ=114.08 cm-1. The final R factor was 6.4 % for 3050 ref1eetions with Iσ(I). The cation HO+3 is coordinated by eight oxygen atoms which have a dodecahedron configuration (symme - try D2d). The coordination polyhedrons are linked together by a TDTD group that coordinates two neighbouring cations HO+3, giving rise to an infinite chain along the crystallographic a direction. The structure of Orrnosalin C14H16O6. Crystal system, monoclinic; space group P21/c; a=10.765(4) Å b=14.692(5) Å c=8.374(4); β=98.02(3)° V=1305(2) , z=4, Dc = 1.43 g/cm3, λ(MoKα)=0.71073 Å, ¿=0.07 mm-1; R=0.058 for 807 reflections with Iσ(I). The structure consists of two five membered rings forming a anti - symmetric twisted conformation