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Molecular tectonics based on fluorinated porphyrins / Tectonique moléculaire à base de porphyrines fluoréesVulpe, Elena 29 September 2015 (has links)
Les travaux décrits dans ce manuscrit utilisent les principes de la tectonique moléculaire pour générer des polymères de coordination hautement fluorés et /ou chiraux pour une application potentielle en séparation chirale. La synthèse de 13 porphyrines de type A2B2 substituées en position méso par deux pyridines et par deux chaines fluorées et/ou alkyles a été mise au point. Des réseaux de coordination ont été obtenus en présence de Zn(II) et de Cd(II) et caractérisés par diffraction des RX sur monocristal (DRX). Une analyse systématique des interactions supramoléculaires et notamment de interactions F---F présentes à l’état solide a été conduite. Des réseaux à base de liaisons halogènes ont également été obtenus en présence de di- et tri-iodoarènes et caractérisés par DRX.Le premier chapitre est une introduction générale sur la tectonique moléculaire, le deuxième chapitre décrit les voies des synthèses utilisées pour générer les ligands chiraux et fluorés et leur caractérisation à l’état solide. Le troisième chapitre présente la structure des réseaux mono, bi, et tridimensionnels formés en présence de Zn(II) ou de Cd(II), l’analyse structurale met en évidence un nombre croissant d’interaction F---F en fonction du nombre de fluors présents à la périphérie du macrocycle porphyrinique. Le dernier chapitre se concentre sur l’utilisation des liaisons halogènes de type N---I impliquant des porphyrines ou des tectons de type bipyridine et une série d’ iodofluoroarenes. / This manuscript focuses on the use of molecular tectonics to generate chiral and / or fluorinated coordination polymers based on porphyrin building blocks for potential application in chiral separation. Synthesis of novel A2B2 fluorinated porphyrin tectons is described and their combinations with metal ions and haloarenes molecules are characterized by X-Ray diffraction.The first chapter gives a general introduction on molecular tectonics; the second chapter focuses on the synthetic routes used for the synthesis of highly fluorinated and/or chiral porphyrins and their solid state characterization by X-Ray diffraction analysis, highlighting the importance of the number of fluorine atoms present at the periphery of the tecton on the crystal packing. The third chapter presents the mono-, bi- and three dimensional networks formed by a combination of the porphyrins with Zn(II) or Cd(II). In the solid state, short F---F contacts were observed depending on the number of fluorine atoms present on the porphyrin backbone. The last chapter focuses on the use of halogen bonds, by merging the neutral porphyrin or bipyridine tectons with a series of iodofluoroarenes. The crystalline materials described in this work can be used as potential candidates for the separation of chiral and fluorinated molecules.
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Synthesis of potential opioids based on the natural PawhuskinsGardner, Kevyn Danielle 01 May 2016 (has links)
Living organisms are capable of producing novel terpenoids with both remarkable ease and great selectivity. Many of these natural products exhibit significant biological activity useful for treatment of human diseases, but isolation of highly sought chemicals often results in only minute quantities. Consequently, extraction of these potential therapeutics from natural sources becomes an unrealistic method for obtaining enough material for a thorough biological evaluation, and so synthesizing these compounds becomes essential. Synthesis of terpenoids as potential therapeutics requires exceptional selectivity, especially when corresponding isomers elicit a contrasting biological response. The necessity for such selective syntheses along with the inherent structural complexities of terpenoids, often presents a number of significant challenges for the synthetic chemist.
Isolation of the terpenoids pawhuskins A–C and petalostemumol from Dalea purpurea was reported by Belofsky in 2004, and of the collected compounds pawhuskin A was found to exhibit the most significant activity in an opioid receptor assay in vitro. Natural pawhuskin A was extracted from “Purple Prairie Clover” in only a 39 mg quantity and therefore syntheses of the natural product along with several analogues were pursued. Two of the synthesized analogues demonstrated greater potency than pawhuskin A, and interestingly these two isomeric derivatives were found to be selective for two different opioid receptors. However, the synthetic route utilized to form these two derivatives was not very selective for either isomer, and thorough purification proved challenging. Ergo, an alternative approach was sought to ensure the purity of these potential therapeutics.
Parallel syntheses affording high selectivity for the key isomeric intermediates as well as a third regioisomer have been developed. The new isomeric intermediate also allowed the synthesis of two new analogues. This work is described in this report along with the formation of additional pawhuskin derivatives. The activity of these analogues as opioid receptor modulators also will be discussed.
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Photodissociation Dynamics of Halogen Oxide SpeciesDooley, Kristin S. 2009 May 1900 (has links)
The focus of this dissertation is the study of the photodissociation dynamics of
halogen oxide species (XO, X = Cl, Br, I). These radical species are known to be
important in stratospheric and tropospheric ozone depletion cycles. They are also useful
benchmark systems for the comparison to current theoretical methods where they
provide insight into the dynamics occurring beyond the Franck-Condon region. These
systems are studied using velocity map ion imaging, a technique that measures velocity
and angular information simultaneously. Photofragment species are state-selectively
ionized for detection using 2+1 REMPI (Resonance Enhanced Multi-Photon Ionization).
The instrumentation employs a molecular beam of the XO radicals formed using
pyrolitic and photolytic methods.
The current work involves the measurement of fundamental physical constants of
the XO species. The bond dissociation energy of IO is measured. Vibrational level
dependent correlated final state branching ratios of the predissociation of the A(^2 II_3/2)
state of ClO and BrO are reported, and comparison to theoretical methods is discussed.
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Chemistry of highly halogenated cyclopentadiene dimers and cages /Tang, Datong. January 2002 (has links)
Thesis (Ph. D.)--University of Chicago, Department of Chemistry, 2002. / Includes bibliographical references. Also available on the Internet.
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Chemical and physical aspects of wear processes in polymersRichardson, M. O. W. January 1972 (has links)
A series of homogeneous halogen containing polymers have been studied whilst sliding against mild steel and oxides present on mild steel. The degradation characteristics of P. V. C. and C1d P. V. C. have been correlated in terms of current mechano-chemical comminution theory and the process causing the wear of P. V. C., C1d P. V. C., P. T. F. E. and P. C. T. F. E. described in relation to the chemical and physical conditions at the sliding interface. In addition the potential importance of the chemical role of oxide free iron surfaces in wear processes has been demonstrated by interacting an analogue compound of P. T. F. E. (n-C5F12) with clean iron under ultra high vacuum conditions. The resulting fragmentation of the perfluorinated compound is discussed and a simplified degradation mechanism suggested.
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Interlocked host structures for anion recognition and sensing in aqueous solutionsLangton, Matthew J. January 2014 (has links)
This thesis describes the synthesis of interlocked anion host systems which exploit hydrogen bonding, halogen bonding, and lanthanide-coordination for anion recognition and sensing in aqueous solution. Chapter 1 introduces the field of anion supramolecular chemistry, with particular focus on areas of particular relevance to this thesis, namely anion recognition and sensing, anion templation and the synthesis of interlocked structures. Chapter 2 describes the synthesis of hydrogen bonding rotaxane and catenane hosts for recognising and sensing oxoanions in aqueous solvent media. The novel use of nitrate anion templation for the synthesis of interlocked molecules is reported, and the unprecedented selective recognition of nitrate in aqueous solvent media is demonstrated. Chapter 3 details the preparation of water soluble permethylated β-cyclodextrin-stoppered rotaxane hosts that utilise halogen bonding and hydrogen bonding interactions to bind anions in pure water. The first thermodynamic investigation into halogen bonding in water is reported, and the relative capabilities of halogen and hydrogen bonding for anion recognition in water are compared. Chapter 4 investigates the incorporation of lanthanide cations into rotaxane hosts for optical anion sensing. The seminal use of lanthanide cation templation for interlocked molecule synthesis is described, before anion templation approaches towards the synthesis of lanthanide-based rotaxanes are discussed. The luminescence anion sensing capabilities of these interlocked hosts are investigated. Chapter 5 describes the experimental procedures used in this work, and details the characterisation of compounds presented in Chapters 2–4. Chapter 6 summarises the conclusions of this thesis.
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Closing the Lab-to-Fab Gap with Inkjet-Printed Organic PhotovoltaicsAlmasabi, Khulud M. 08 August 2019 (has links)
Inkjet printing promises to be an invaluable technique for processing organic solar cells with key advantages such as low material consumption, freedom of design and compatibility with different types of flexible substrates making it suitable for large-area production. However, one concern about inkjet printed organic solar cells is the common use of chlorinated solvents during the ink formulation process. While chlorinated solvents suit the inkjet printing process due to their high boiling points, suitable viscosity, and excellent solubility of organic donor and acceptor compounds, they still pose some risks for both human health and the environment, excluding them from being the ultimate choice for large-area production.
As a step towards commercialization of OPV, we demonstrated the possibility to close the laboratory to fabrication gap, through the engineering of environmentally friendly inks, using a blend of non-halogenated benzene derivatives solvents optimized to meet the viscosity and surface tension requirements for the inkjet printing process.
Starting from using the non-fullerene acceptor O-IDTBR combined with the commercially available donor polymer P3HT we obtained solar cell device with efficiency up to 4.73% - the best efficiency achieved by the P3HT:O-IDTBR system processed with all non-halogenated solvents via inkjet printing. We also delivered highly transparent active layer with device power conversion efficiency of up to 10% with a highly efficient blend of polymer donor PTB7-Th in combination with the ultranarrow band gap NFA IEICO-4F, using hydrocarbons solvent.
Lastly, we demonstrated both high efficiency, transparency, and stability by presenting a novel approach based on NFAs consisting of lowering the donor:acceptor ratio in the photoactive layer ink formulations, resulting in more stable devices with comparable power conversion efficiencies to those achieved by lab methods.
This breakthrough in ink engineering paves the way in closing the lab-to-fab gap in organic photovoltaic using the low-cost, high throughput inkjet printing technology while considering both environmental and health-conscious mass production and device stability of organic photovoltaics.
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Porovnání výsledků experimentálních měření dohlednosti s dostupným software / Comparison of Results of Experimental Visibility Measurements with Available SoftwareOndris, Róbert January 2012 (has links)
Master's thesis evaluates determined values of visibility from the motor vehicle on the pedestrian by reduced visibility distance when using halogen headlights, which are the results of experimental measurements a compare them with theoretical values determined by assistance of available software.
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Det som går förlorat när halogenlamporna försvinner : En studie om skillnaden i ljus mellan halogen och LED-lampor och dess påverkan hos en publik / That which is lost when tungsten lights disappear : A study of the differences in light between tungsten and LED-lights and it´s impact on an audienceMarkström, Daniel, Ahlros, Johannes January 2019 (has links)
Det huvudsakliga syftet med denna uppsats är att undersöka vilken påverkan valet av ljusteknik, LED eller halogen har på den slutliga produkten. Studien kommer med hjälp av fokusgruppsintervjuer undersöka om personer kan se skillnad på en ljussättning som är gjord med LED- respektive halogenlampor samt vad de olika teknikerna ger för känsla. Vi jämför resultaten från fokusgruppsintervjuerna med tidigare litteratur som Set lighting technician's handbook: film lighting equipment, practice, and electrical distribution och Lighting for cinematography: a practical guide to the art and craft of lighting for the moving image. Fokusgruppsintervjuerna resulterade i något oväntade svar och gav oss en bredare och förtydligad förståelse för vad som spelar roll när det kommer till en publiks känslomässiga reaktion av en bild.
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Kinetics and Thermochemistry of Halogenated SpeciesMisra, Ashutosh 05 1900 (has links)
Gas phase kinetics and thermochemistry of several halogenated species relevant to atmospheric, combustion and plasma chemistry were studied using experimental and ab initio theoretical techniques.
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