A proven strategy, donor-acceptor approach, to reduce the band gap of conjugated materials and possibly improve the photocurrent is to incorporate electron-rich and electron-deficient units in an alternating fashion in a polymer chain. For this purpose, a wise selection of donor and acceptor moieties in a monomer structure results in desired finishing properties of polymeric materials. In this study, fourteen novel monomers were synthesized to explore the acceptor and donor effects on the electronic and optoelectronic properties. Dibenzophenazine, dibenzopyrido]quinoxaline, tetrahydro- dibenzophenazine, thiadiazoloquinoxaline, pyrazinoquinoxaline, thienopyrazine, benzoselenadiazole, thienoselenadiazole were used as acceptor moieties, while thiophene, 3-hexylthiophene and 2,3-dihydrothienodioxine (EDOT) were used as the donor components in these donor-acceptor molecules. To synthesize desired monomers, well-known synthetic methods were performed, including bromination, nitration, reduction and condensation. Bromination was achieved by two different ways depends on the aim, NBS and Br2/HBr medium. For the nitration, HNO2 and H2SO4 were used together. Fe metal in refluxing acetic acid was used as the reducing agent in case of nitro group reductions. On the other hand, Zn metal/AcOH system was chosen for the reduction of both nitro groups and thiadiazole structure to amine, simultaneously. Finally, the Stille Coupling was used to obtain resulting acceptor-donor-acceptor monomers. These synthesized monomers were polymerized by electrochemically and investigated their properties by methods such as spectroelectrochemistry, kinetic and colorimetry studies. Spectroelectrochemistry experiments were performed in order to investigate key properties of conducting polymers such as band gap, maximum absorption wavelength, the intergap states that upon doping and evolution of polaron and bipolaron bands. Switching time and optical contrast of the polymers were evaluated via kinetic studies.

Thesis (doctoral)--Universität St. Gallen, 2003.

To date, the subject of disability has been highly disregarded in Germany’s academia. In the field of Arts, the topic is a derivative. This thesis makes a contribution to the discipline of Disability Studies and approaches the problematic from the field of German Studies. The analysis focuses on the sensory disabilities deafness and blindness and its depiction in the movies Jenseits der Stille und Erbsen auf Halb Sechs. The goal of this paper is to attract notice to the ways of representation of disability in German media in general. On the one hand, film reflects generally accepted public attitudes. But since film is a mass media, it has the potency to alter and question the communal opinion on the other hand. Thus, it can change society’s mindset about people with disability. Furthermore, this paper points out the different starting points for further liberal arts oriented approaches for investigations of disability in the media. However, the film analysis is based on two theses. The first one claims that the focus in the representation of people with disability does not concentrate on the human beings. On the contrary, it rather concentrates on the disability itself and the consequences that spring of it. The second thesis pursues this thought and says that the movies not only focus on the depiction of disability. In fact the disabled figures define themselves by their handicap and, in return, are defined by their physical aberrance by their social surroundings, which is foremost not disabled. Thereby, the disability forms an almost insuperable interpersonal obstacle. The analysis of the two movies is done along three research questions. The first one concerns the connection of physical handicap and the way people with disability think and act in relation to their surroundings and life in general. The second question is what factors, like gender, social class, or age, are crucial in self- and external perception, and therefore, in the formation of identity. The last investigation concentrates on the special abilities of people with disability, and scrutinizes if the aptitudes serve as compensations for their disabilities. The basis of this paper is Michel Foucault’s theory of mechanisms of societal exclusion, and the construction of categories such as norm and abnormity. Especially his works Wahnsinn und Gesellschaft, Überwachen und Strafen and his lecture course of Die Anormalen are essential in this perspective. In addition, the cultural and social currents in the disability studies serve as fundamental approaches. These two theories help to identify the vague term disability, and consequently, the object of investigation in this paper. In summary, the analysis of Jenseits der Stille and Erbsen auf Halb Sechs shows that the representation of disabled people in German film is predominantly stereotypic. Therein, disablement means great misfortune, and the loss of the central position in discourse. The disabled figures are socially alienated from their non-disabled surroundings. The isolation, however, is brought about by discursive mechanisms such as the power of medicine. In both movies, the disabled and non-disabled people are focused on the disability in their self and external perception. Accordingly, disability is linked to the feeling of shame, a lack of acceptance and the stigmatization of deviants. Self-acceptance can only be accomplished outside of the discourse of the normal, in which disabled are stigmatized. This paper reveals that the representation of people with disability in German film still shows a rather stereotypic image. Therefore, they tend to confirm societal prejudices rather than to challenge them.

Studies toward the total synthesis of (+)-providencin (1), a highly oxygenated cembranoid dipterpene with a unique bicyclo[12.2.0]hexadecane skeleton and pronounced biological activity, are described. These studies resulted in the synthesis of advanced intermediates 320 and 332 which contain all of the carbon atoms of 1. In a first generation approach toward 1, a zirconium-mediated deoxygenative ring contraction of furanose 177 was used to furnish enantiopure cyclobutanol 176. Olefination of furan aldehyde 197 with phosphonate 214 completed cyclobutylfuran segment 215. A second generation approach toward cyclobutylfuryl subunit 221 via ring-closing metathesis of diene 237 was unproductive, but the iodolactone subunit 228 needed for 1 was prepared successfully using carbometallation-iodination of alkyne 231. Nucleophilic substitution of tosylate 230 with the dianion of phenylselenyl acetic acid (252) followed by acid-catalyzed lactone formation was employed for construction of the γ-lactone moiety of 228. A third generation route to the cyclobutylfuryl subunit of 1 involved a tin(II) chloride-mediated stereoselective allenol synthesis by reaction of aldehyde 302 with propargyllic bromide 264. A silver-catalyzed allenone-to-furan isomerization of 309 completed the synthesis of cyclobutylfuran subunit 288. Attempts to couple the two major fragments, 228 and 288, using palladium-catalyzed C-H activation of the furan component were unsuccessful, but linkage of two major subunits was achieved at the C12-C13 bond via an intermolecular aldol reaction to give 332 and at the C6-C7 bond using intermolecular palladium-catalyzed cross-coupling to afford 320. / Graduation date: 2012

No description available.

Les performances des cellules photovoltaïques organiques de type hétérojonction en volume sont entre autres influencées par les propriétés opto-électroniques du polymère semiconducteur donneur d’électrons. L’objectif de cette thèse était de développer de nouveaux polymères π-conjugués pour permettre une meilleure exploitation du spectre solaire et donc améliorer la photogénération des charges. Pour cela, plusieurs dérivés de polythiophènes comportant des substituants aromatiques phényles ont été synthétisés par la méthode de GRIM, à noter l’homopolymère poly[(3-(4-hexylphényl) thiophène] (P3HPT) et le copolymère à blocs poly[3-(4-hexylphényl)thiophène]-bloc-poly(3-hexylthiophène) (P3HPT-b-P3HT). Nous avons également étudié une nouvelle famille de polymères à faible bande interdite basés sur l’alternance d’unités thiophène et dithiéno[3,2-b:2′,3′-d]silole riches en électrons et 2,1,3- benzothiadiazole pauvres en électrons. Après synthèse des différents monomères, les copolymères alternés ont été ensuite obtenus par polycondensation par couplage de Stille. Les différents matériaux synthétisés ont été d’abord caractérisés par analyse thermogravimétrique et par calorimétrie différentielle à balayage afin d’étudier leurs propriétés thermiques. Ensuite, des caractérisations structurales (en particulier DRX et neutrons), optiques (UV-visible) et morphologiques (AFM) ont été réalisées. A partir des résultats obtenus, nous avons pu évaluer les relations entre les structures et les propriétés des matériaux. Finalement, des cellules photovoltaïques à base des polymères synthétisés ont été réalisées et leurs performances ont été corrélées aux propriétés des matériaux. / The performances of organic solar cells based on the concept of bulk heterojunction configuration are strongly influenced by the optoelectronic properties of the electron donor polymer. The aim of this thesis was to develop new π-conjugated polymers to allow a better exploitation of the solar spectrum and thus improving the photogeneration of charges. For this,several polythiophene derivatives substituted by phenyl aromatic groups have been synthesized by the GRIM method, note the homopolymer poly[(3-(4-hexylphenyl)thiophene] (P3HPT) and the diblock copolymer poly[3-(4- exylphenyl)thiophene]-block-poly(3- hexylthiophène) (P3HPT-b-P3HT). We also studied a new family of low band gap polymers based on the alternation of electron-rich thiophene and dithieno[3,2-b:2′,3′-d]silole units andelectron-deficient 2,1,3-benzothiadiazole units. After synthesis of the various monomers, alternating copolymers were then obtained by Stille cross-coupling polycondensation. The different synthesized materials were first characterized by thermogravimetric analysis and by differential scanning calorimetry to study their thermal properties. Then, structural(especially XRD and neutron), optical (UV-visible) and morphological (AFM) characterizations were performed. From the obtained results, we were able to evaluate the relation between structures and properties of materials. Finally, photovoltaic cells based on the synthesized polymers were performed and their performances were correlated to material properties.

Ces dernières années, un nouveau type de polymère donneur d’électron pour des applications photovoltaïques a été étudié de manière intensive, les copolymères à faible bande interdite. Ils sont constitués d’un groupement riche en électron (ER) et d’un groupement pauvre (EP) permettant de contrôler les orbitales frontières et d’induire une délocalisation de l’exciton généré lors du processus de photo-excitation. Une large variété de dispositifs est basée sur ces copolymères avec des rendements d’environ 10% et, pour accroitre leur efficacité, il est nécessaire d’avoir une meilleure compréhension de ces polymères pendant le phénomène de photo-absorption. La chimie théorique apparait comme un outil permettant de prédire différentes propriétés optoélectroniques. Au cours de ce travail, nous avons utilisé la théorie de la fonctionnelle de la densité indépendante (DFT) et dépendante du temps (TD DFT) pour simuler les propriétés optiques d’oligomères de taille croissante avec différents groupements ER et EP. Les propriétés optiques des polymères correspondant ont été extrapolées à l’aide du modèle de Kuhn. Ce criblage théorique nous a permis de sélectionner des systèmes prometteurs à base de benzodithiophène, de benzothiadiazole et de benzofurazane qui ont ensuite été synthétisés par couplage de Stille. Les polymères et oligomères obtenus ont été caractérisés par spectroscopie UV-visible et de fluorescence, chromatographie d’exclusion stérique et par RMN dans le but d’observer des relations structure-propriétés et de faire des corrélations entre résultats expérimentaux et théoriques. / During the last decade, a new kind of donor polymers for photovoltaic application have been intensively studied, the low band-gap polymers. They are based on repeating units associating two different moieties, one electron-rich (ER) and one electron-poor (EP), which allow to finely tune the molecular orbitals and to induce a delocalization of the exciton generated upon the photo-excitation process. A large variety of devices are based on such low band-gap polymers, with a power conversion efficiency record around 10%, and, to increase the efficiency, it is necessary to have a better understanding of these polymers during the photo-absorption phenomenon. Computational chemistry isa powerful tool that permits to predict different opto-electronic properties. For this work, we used Density Functional Theory and Time-Dependent Density Functional Theory to compute the optical properties of increasingly large oligomers involving various ER and EP subunits. The optical properties in the polymer limit were then estimated for the different systems by using an extrapolation scheme based on the Kuhn equation. This theoretical screening allowed us to select promising candidates based on benzodithiophene, benzothiadiazole and benzofurazan for syntheses, which were performed by a Stille coupling. The obtained polymers and size-controlled oligomers were further characterized by UV visible spectroscopy, fluorescence, size exclusion chromatography and NMR, in order to extractstructure-properties relationships and correlate experimental results to theoretical data.

Le couplage de Stille modifié développé par l’équipe du Pr Fouquet a été appliqué à la méthylation de nucléosides, dinucléotides et oligonucléotides dans le but de mettre au point une méthodologie de marquage d’aptamères au carbone 11 pour le diagnostic précoce de cancer par TEP. Ce couplage pallado-catalysé est basé sur l’utilisation de monoorganoétain activé par une source de fluorure permettant d’accélérer la réaction. Dans un premier temps, les essais méthodologiques ont permis de mettre au point le transfert de groupement méthyle sur différents nucléosides et un dinucléotide modifiés dans des conditions compatibles avec la durée de demi-vie du carbone 11 (20,4 min) et la nature particulière des oligonucléotides. Puis, cette méthodologie a été appliquée à des oligonucléotides modèles obtenus après incorporation des nucléosides les plus prometteurs. / The modified Stille cross-coupling developed by Pr. Fouquet’s group was applied to the methylation of nucleosides, dinucleotides and oligonucleotides in order to develop a methodology for labelling aptamers with carbon 11 for the early diagnosis of cancer by PET. This pallado-catalyzed cross-coupling is based on the use of monoorganotin activated by a source of fluoride accelerating the reaction. Initial methodology tests helped to finalize the transfer of methyl group on various nucleosides and a dinucleotide, with reaction conditions compatible with the short half-life of carbon 11 (20.4 min) and the special nature of oligonucleotides. Then, this methodology was applied to oligonucleotide models obtained after incorporation of the most promising nucleosides.

Hovedproblemstillinga i denne undersøkelsen er ” Hvordan oppfatter musikk- og kulturskolelærerne den stille eleven og hvordan legger de opp gruppeundervisningen for å nå denne typen elever i gruppesituasjoner?” For å finne svar på dette brukte jeg kvalitativt forskningsintervju som metode. Fem strykelærere med minimum ti års fartstid og med erfaring fra både individuell- og gruppeundervisning har deltatt. Disse ble håndplukket fra mitt kontaktnett. Resultatet av undersøkelsen viser at lærerne ser på den stille eleven som en som ikke sier så mye og er veldig forsiktig. Utover dette kan det se veldig ulikt ut. For å nå den stille eleven kom det fram at det er viktig å arbeide med hele gruppa for å skape en fellesskapsfølelse, og at de som lærere ser og bekrefter elevene. I diskusjonen har jeg med utgangspunkt i teorier om gruppeprosesser og lederskap, diskutert hvilken betydning musikkundervisning i gruppe og hvilken rolle læreren har i forhold til den stille elevens atferd. / The main question in this survey is "What are experienced music and art teachers’ opinions on the quiet learner, and how do they reach this group of students in group teaching?" To answer this, I used qualitative interviews. Five string teachers with a minimum of ten years of experience and with experience in both individual and group teaching participated. The teachers were handpicked from my contacts. The results of the survey show that teachers see the quiet student as a person who does not say much, and is very careful. Beyond this, every quiet student can look very different. To reach the quiet student, it became apparent that it is important to create a group atmosphere, and that the teachers see and acknowledge the students. During the discussion, I have raised the importance of group teaching in music and the vital part the teacher plays, in relation to the development of quiet students, based on theories about group processes and leadership.

<p>This thesis contains two parts.</p><p>In the first part, general and versatile palladium-mediated ¹¹C-C bond forming reactions for use in the production of radiotracers for Positron Emission Tomography (PET) were explored. Two complimentarty approaches were investigated: the coupling of [¹¹C]methyl iodide with a vinyl stannane and the reaction of a [¹¹C]methylated stannane with various organohalides. The former approach resulted in an improved, fully automated method for the synthesis of the potential cell proliferation tracer 1-(2’-deoxy-2’-fluoro-β-D-arabinofuranosyl)-[<i>methyl</i>-¹¹C]- thymine. The tracer was obtained in an isolated decay-corrected radiochemical yield of 28% at 25 min after end of radionuclide production. </p><p>In the latter approach, a [¹¹C]methylated tricyclic stannane (5-[¹¹C]methyl-1-aza- 5-stannabicyclo[3.3.3]undecane) was synthesised in 47% decay-corrected radiochemical yield, starting from [¹¹C]methyl iodide. This stannane was successfully employed in palladium-mediated coupling reactions with aryl, heteroaryl and vinyl halides.</p><p>In the second part, effects of the osmolytes glycine betaine, trimethylamine <i>N</i>-oxide (TMAO) and urea on Ribonuclease A (RNase A) were investigated using Nuclear Magnetic Resonance (NMR) spectroscopy. Changes in the enzymatic activity in the presence of these osmolytes at concentrations of ≤1 M were observed by monitoring the RNase A-catalysed degradation of polyuridylic acid using ³¹P NMR spectroscopy. The decrease in activity caused by urea was counteracted by both glycine betaine and TMAO at a molar ratio of 1:1.4 and 1:1, respectively.</p><p>To investigate if the observed activity changes were accompanied by any detectable alteration in the gross conformation of RNase A, diffusion coefficients for the enzyme in the various osmolyte solutions were measured using pulsed-field gradient NMR. A pulse sequence suitable for diffusion measurements in highly concentrated aqueous osmolyte solutions was developed and assessed. The diffusion of RNase A was measured relative to a new internal standard, 2,2,5,5,-tetramethyl-1,4-dioxane. No clear, detectable change in the relative diffusion of RNase A was observed in these media.</p>