Submitted by Bruna Andressa Bregadiolli null (brunabregadiolli@hotmail.com) on 2016-11-14T15:01:32Z No. of bitstreams: 1 these Bruna final revisada.pdf: 6701827 bytes, checksum: ff6657984f5cc54c2e587577fbdcfe83 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-11-21T12:28:44Z (GMT) No. of bitstreams: 1 bregadiolli_ba_dr_bauru.pdf: 6701827 bytes, checksum: ff6657984f5cc54c2e587577fbdcfe83 (MD5) / Made available in DSpace on 2016-11-21T12:28:44Z (GMT). No. of bitstreams: 1 bregadiolli_ba_dr_bauru.pdf: 6701827 bytes, checksum: ff6657984f5cc54c2e587577fbdcfe83 (MD5) Previous issue date: 2016-09-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Ce travail vise à étudier et à développer des matériaux pour des applications dans les cellules solaires de troisième génération. Les matériaux synthétisés sont des dérivés de fullerène, l'oxyde de titane et des nanoparticules hybride (polymère@oxyde). Les polymères dérivés de fullerène, de type n, ont été conçues pour contenir C60 dans la chaîne principale. Trois produits différents ont été obtenus, en faisant varier la longueur du comonomère en utilisant une nouvelle voie de polymérisation. Les dispositifs photovoltaïques ont été préparés en utilisant la configuration à hétérojonction en vrac et le rendement le plus élevé atteint était de 1,84 %, ce qui représente une performance prometteuses pour un nouveau matériau. Les nanoparticules de dioxyde de titane ont été synthétisés en utilisant la technique hydrothermique assistée par micro-ondes dans différentes conditions de réaction, tels que le pH, la température et le temps, afin d'obtenir ainsi défini nanométrique morphologie, avec des rendements élevés et une grande surface spécifique. En outre, on a étudié l'influence des ions Na+ sur la croissance cristalline des oxydes et morphologies des oxydes, où c'etait obtenu des nanoparticules, des aiguilles et des structures ressemblant des nanotubes. Les nanoparticules hybrides ont été synthétisés en utilisant l'oxyde synthétisé et un polymére, P3HT, fonctionnalisés afin de lier de manière covalente avec les oxydes. Les nanoparticules sont optiquement caractérisés et ont conclu à être possible d'utiliser pour les études de transfert de charge dans les systèmes hybrides. / Este trabalho tem como objetivo estudar e desenvolver materiais para aplicações em células solares de terceira geração. Os materiais sintetizados são derivados de fulereno, óxido de titânio e nanopartículas híbrido (óxido@polímero). Os polímeros derivados de fulereno, de tipo n, foram planejados para conter C60 na cadeia principal. Três produtos diferentes foram obtidos, variando o comprimento da cadeia alquílica do co-monômero utilizando uma nova rota de polimerização. Os dispositivos fotovoltaicos foram preparados utilizando a configuração de heterojunção no volume e a maior eficiência alcançada foi de 1,84 %, o que representa um desempenho promissor para um novo material. As nanopartículas de dióxido de titânio foram sintetizadas usando a técnica hidrotermal assistida por micro-ondas em diferentes condições reacionais, tais como pH, temperatura e tempo, de modo a obter a morfologia nano dimensionada bem definida, rendimentos elevados e alta área superficial. Além disso, estudou-se a influência dos íons Na+ no crescimento cristalino dos óxidos e em sua morfologia, onde foram obtidas nanopartículas, estruturas tipo agulas e estruturas tipo nanotubos. As nanopartículas híbridas foram sintetizadas utilizando os óxidos sintetizados e um polímero, P3HT, funcionalizado de modo a ligar-se covalentemente aos óxidos. As nanopartículas foram opticamente caracterizadas e concluímos que estas podem ser utilizadas para estudar a transferência de carga em sistemas híbridos. / This work aims to study and develop materials for applications in third generation solar cells. The synthesized materials are fullerene derivatives, titanium oxide, and hybrid (polymer@oxide) nanoparticles. The fullerene derivatives, n-type polymers, were designed to contain C60 in the main chain. Different products were obtained, varying the comonomer alkyl length using a new polymerization route discovery in this work. The photovoltaic devices were prepared using the bulk heterojunction configuration and the highest efficiency reached was 1.84 %, representing a very promising performance for a novel material. The titanium dioxide nanoparticles were synthesized using microwave assisted hydrothermal technique in different reaction condition, such as pH, temperature and time, in order to obtain well defined nano-sized morphologies, high yields and high surface areas. Also, it was investigated the influence of the Na+ ions on the crystalline growth and morphologies of the oxides, where nanoparticles, needles and nanotube-like structures were obtained. The hybrid nanoparticles were synthesized using the prepared oxides and a P3HT functionalized in order to bond covalently with the oxides. The nanoparticles were optically characterized and concluded to be possible to use for studies of charge transfer in hybrid systems. / FAPESP: 2011/02205-3 / CAPES: 11216-12-3

Le but de cette thèse était d’auto-assembler des entités triarylamines donneurs d’électrons et capables de s’empiler en fibres conductrices sous l’action de la lumière, avec des entités accepteurs d’électrons de manière à obtenir des hétérojunctions supramoléculaires. Ces objectifs ont été atteints dans des versions dites statiques (distances constantes entre canauxdonneur et accepteur d’électrons) mais aussi dans une version dynamique ou la distance entre unités électroactives change grâce à l’action contrôlée d’un muscle moléculaire intégré. Ces systèmes auto-assemblés fonctionnels ont montré des changements très importants de leurs propriétés optoélectroniques en réponse à des stimuli orthogonaux comme la lumière et le pH. / The aim of this thesis was to self-assemble electron-donating triarylamine units, capable of aggregation into conducting fibers triggered by light, with electron-accepting entities to obtain supramolecular heterojunctions. These objectives were attained, that is in static versions (with constant distances between electron-donating and -accepting channels) and in a dynamicversion wherein the distance between the electroactive units changes owing to the controlled action of an integrated molecular muscle. These functional self-assembled systems showed very important changes in their optoelectronic properties in response to orthogonal stimuli such as light and pH.

Orientador: Fernando Alvarez / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-09T10:47:17Z (GMT). No. of bitstreams: 1 ParedezAngeles_PabloJenner_D.pdf: 4194390 bytes, checksum: 8881d83ee8bcb5a5ad4bfb23b7ff1028 (MD5) Previous issue date: 2007 / Resumo: Nesta tese são apresentados os efeitos nas propriedades estruturais, eletrônicas e de emissão eletrônica por efeito de campo elétrico induzidos pela incorporação de nitrogênio em nanoestruturas de carbono. As nanoestruturas de carbono contendo nitrogênio foram preparadas por pulverização catódica (sputtering) de um alvo de grafite assistido, ou não, por um feixe iônico. A técnica permite atuar sobre os parâmetros de deposição induzindo mudanças nas propriedades estruturais, eletrônicas e de emissão eletrônica por efeito de campo elétrico. O papel do hélio na formação de nanoes-truturas de carbono contendo nitrogênio foi também explorado, mostrando que o gás nobre promove maior incorporação de nitrogênio. Isto é provavelmente devido à relativa alta condutividade térmica que apresenta o hélio, propriedade que modifica a cinética do crescimento das nanoestruturas. O estudo realizado permitiu entender o mecanismo de formação das nanoestruturas, mostrando que primeiramente o carbono alcança as partículas de Ni por difusão até a saturação do metal, iniciando a formação das camadas grafíticas sobre a partícula de Ni, camadas que foram observadas por microscopia eletrônica de transmissão de alta resolução. O estudo mostra, também, que os parâmetros importantes que controlam a incorporação de nitrogênio no material são a pressão parcial de nitrogênio na câmara de deposição, assim como a energia do feixe de íons assistindo a deposição.Foram estudadas três séries de amostras preparadas em atmosferas controladas. Na primeira série foi utilizado um feixe de íons de nitrogênio como feixe de assistência, e na segunda, uma mistura composta por duas espécies iônicas, íons de nitrogênio e hidrogênio. Com o auxilio da espectroscopia de elétrons fotoemitidos por raios-X observou-se a incorporação de nitrogênio nos filmes. A microscopia de força atômica revelou a presença de estruturas do tipo domo, distribuídas de maneira uniforme na superfície das amostras, apresentando uma densidade média de ~3×10 9 domos/cm 2as da primeira série, e ~1.4×10 9 domos/cm 2as da segunda série. Tanto a distribuição como a forma seguem o padrão estabelecido pelos precursores utilizados na preparação das nanoestruturas, i.e., ilhas de níquel que agem ao mesmo tempo como catalisadores e como suporte para as nanoestruturas. Na terceira série, as nanoestruturas foram crescidas sobre um filme de nitreto de titânio, depositado sobre substratos de Si, pulverizando um alvo de grafite em atmosferas de nitrogênio e hélio-nitrogênio. A densidade dos domos encontrada para esta série foi de ~5.3×10 10 domos/cm 2 . Os espectros Raman das três séries apresentam as bandas G e D, o que indica a presença estruturas grafíticas com distorções representadas pela banda D. A incorporação de nitrogênio ocasiona o alargamento da banda G e aumento da razão das intensidades das bandas D e G, respectivamente, indicando uma redução da ordem estrutural com a incorporação de Nitrogênio. Finalmente, para as três séries de amostras, fez-se também um estudo das propriedades de emissão eletrônica por efeito de campo elétrico. A emissão é predominantemente por tunelamento quântico (as curvas de densidade de corrente vs campo elétrico seguem o modelo de Fowler-Nordheim) e dependem da concentração de nitrogênio assim como do processo usado na preparação das amostras / Abstract: The subject of this thesis is establishing a link among the synthesis, structures, and field emission properties for nanostructured carbon materials containing nitrogen. The materials were prepared by ion beam assisted deposition and ion beam sputtering. The carbon material was obtained sputtering an ultra pure graphite target by an argon ion beam. The method allows controlling the deposition parameters to induce changes in the structural, electronic, and field emission properties. Also, the role of helium on the carbon containing nitrogen nanostructures was investigated. The remarkable thermal conductance of He modifying the growing kinetics was also studied. An important goal of the work was to elucidate the mechanism of the nanostructures formation. It was found that, at first, the carbon atoms reach the Ni particles saturating the metal particle, and then, the formation of stacked graphene starts on the metal particles. The graphene layers were observed by high resolution transmission electron microscopy. The results show that mainly two parameters control the nitrogen incorporation, namely, the deposition chamber nitrogen partial pressure and the energy of the nitrogen ion beam assisting the growth. Three sample series prepared in controlled atmospheres were studied. The first series was prepared assisting the growth with a nitrogen ion beam and, the second series by a nitrogen-hydrogen ion beam. The third sample series were prepared by ion beam sputtering on silicon substrate by sequentially depositing titanium nitride thin film, nanometric nickel particles and carbon. The carbon containing nitrogen nanostructures were grown in nitrogen and helium-nitrogen atmospheres. X-ray photoelectron spectroscopy analysis indicates nitrogen incorporation and it depends predominantly on the ion beam energy or on the nitrogen partial pressure. Atomic force microscopy reveals dome-like structures uniformly distributed on the surface of the samples, with ~3×10 9 domes/cm 2 for the first series, ~1.4×10 9 domes/cm 2 for the second, and ~5.3×10 10 domes/cm 2 for the third. Both distribution and shape follow the Ni island pattern, i.e. the Ni islandsact both as a catalytic and uphold. The three samples series were also analyzed by Raman spectros-copy, showing a defined G bands around 1593 cm -1 indicating the presence of graphitic structures. Also, are observed D bands indicating structural disorder. The disorder increases with the augment of the nitrogen content, as is shown by the augment of the D and G intensities ratio. Finally, the field emission properties of the three series were studied and the electron emission depends on the growing conditions in general, and on the nitrogen content in particular. The results show that the emission is predominantly by quantum tunneling and the current density vs. electric field curves follow the Fowler-Nordheim model / Doutorado / Física / Doutor em Ciências

Les enjeux environnementaux actuels, ainsi que la hausse continue du prix du pétrole, ont incité les constructeurs automobiles du monde entier à améliorer le rendement de leurs véhicules. Les propriétés tribologiques des lubrifiants des moteurs et boîtes de vitesses ont une influence considérable sur le rendement global des véhicules. Ils réduisent en effet le frottement généré par un grand nombre de contacts, et permettent parfois la réduction de la taille de différents composants en leur conférant une meilleure résistance à l’usure. Les avancées récentes en termes de synthèse de nanoparticules ont ouvert de nouvelles perspectives en termes d’additivation de lubrifiants avec, par exemple, la découverte des excellentes propriétés tribologiques des nanoparticules inorganiques de type fullerène comme le disulfure de molybdène ou de tungstène. L’objectif de ce manuscrit est d’évaluer le potentiel tribologique des nanoparticules IF-MoS2 dans l’optique d’une application automobile. L’influence de la taille et de la structure des nanoparticules a d’abord été étudiée. Les nanoparticules peu cristallines se sont révélées être plus aptes à maintenir un tribofilm performant sur des surfaces en acier dans des conditions de lubrification limite, indépendamment de leur taille. Toutes les nanoparticules testées ont cependant atteint des performances équivalentes lorsqu’une recirculation de l’huile était imposée, permettant de maintenir une alimentation continue du contact en nanoparticules. Une fois incorporées dans une formulation d’huile complète, les nanoparticules IF-MoS2 perdent leurs propriétés tribologiques. Les dispersants contenus dans l’huile, bien que permettant une bonne dispersion des IF-MoS2, semblent responsables de leur inefficacité en empêchant la formation de tribofilms sur les surfaces antagonistes. Une fois correctement dispersées, les nanoparticules pénètrent toujours le contact et se retrouvent bien exfoliées. Une adsorption excessive des dispersants sur les feuillets de MoS2 ainsi libérés et/ou sur les surfaces en acier semble nuire à l’adhésion du tribofilm. Un équilibre entre dispersion des nanoparticules et performance tribologique a ensuite été trouvé, en utilisant de très faibles concentrations de dispersants. Le comportement des huiles dopées en nanoparticules dans des conditions plus proches d’une application automobile a finalement été exploré. Les IF-MoS2 ont permis une réduction significative du frottement et de l’usure à température ambiante et en roulement/glissement, à la fois pour des surfaces lisses et rugueuses. Les risques associés à la présence de nanoparticules dans l’huile dans les régimes de lubrification en film complet ont été partiellement levés. Aucun impact significatif n’a en effet été constaté sur le coefficient de frottement pour l’ensemble des conditions d’essais retenues. Le potentiel des nanoparticules IF-MoS2 pour la protection des surfaces soumises à la fatigue de contact a enfin été démontré. / The growing environmental concerns, along with the continuous increase in the price of fossil fuels, have highly motivated car manufacturers worldwide to improve the efficiency of their vehicles. The tribological properties of engine and gearbox lubricants have a significant impact on the global efficiency of vehicles, as they contribute to reducing friction in many contacts and allow the downsizing of various components by providing their surfaces with anti-wear protection. The recent breakthroughs in nanoparticle synthesis have opened new prospects in terms of lubricant additivation, with the discovery of the excellent friction and wear reducing properties of nanoparticles such as Inorganic Fullerene-like (IF-) molybdenum or tungsten disulfides. The tribological potential of IF-MoS2 for automobile applications was investigated in this work. The respective influences of nanoparticle size and structure were first of all studied, revealing that poorly crystalline nanoparticles were more efficient in maintaining low-friction tribofilms on steel substrates in severe boundary lubrication regimes regardless of size (for the range studied). All the nanoparticles tested however showed similar performances when proper oil recirculation was ensured, providing a continuous feeding of the contact in nanoparticles. The IF-MoS2 nanoparticles lost their lubricating abilities when added to fully-formulated lubricants. This behavior was attributed to the presence of dispersants in the oil, which dispersed the nanoparticles effectively but prevented them from forming tribofilms on the rubbing surfaces. The well-dispersed IF-MoS2 were shown to enter the contact and exfoliate, but an excessive adsorption of the dispersants on the released MoS2 platelets and/or the steel surfaces is thought to prevent tribofilm adhesion. A balance between nanoparticle dispersion and tribological performance was then found, by using very low concentrations of dispersants. The behavior of nanoparticle-doped oils in various scenarios related to automobile applications was finally explored. The IF-MoS2 provided significant friction and wear reduction at ambient temperature and in milder rolling/sliding test conditions, for smooth and rough surfaces. The risks related to the presence of nanoparticles in the oil in full-film lubrication regimes were partially lifted, with no significant influence on friction witnessed for all the test conditions considered. The ability of IF-MoS2 nanoparticles to protect steel surfaces from surface-initiated Rolling Contact Fatigue was finally shown.

Analogues aux cyclotrivératrilènes et aux calix[n]arènes, les pillar[n]arènes sont composés de n unités hydroquinoliques et reliés entre elles par un pont méthylénique en position para. Ces macrocycles ont été utilisés en tant que supports fonctionnalisables afin de préparer divers nanomatériaux. Dans ce contexte, la modification chimique du pont méthylénique a été réalisée sur le pillar[5]arène afin d’obtenir un nouveau site de fonctionnalisation, à ce jour jamais exploité. L’oxydation de cette position a permis dans un premier temps de réaliser une extension de cycle par une réaction de Colvin, afin d’obtenir un macrocycle portant une triple liaison tendue. Cette particularité a permis la réalisation de cycloaddition 1,3-dipolaire de Huisgen ou chimie click sans utilisation de cuivre(I), mais également l’obtention de produits de cycloadditions [2+2] par voie thermique normalement interdites. L’introduction d’un fullerène C60 sur ce pont méthylénique a également été réalisée sans déformation de la cavité. C’est pourquoi dans un deuxième temps des [2]rotaxanes photoactifs ont pu être élaborés à partir de ce fulléropillar[5]arène. Dans un dernier temps, une nouvelle méthode de préparation des [2]rotaxanes a été développée. Par échange de bouchons activés, divers [2]rotaxanes ont pu être synthétisés, sans être limités par la nature des bouchons souhaités. A partir de cette méthode de préparation, des cristaux liquides ont pu être obtenus en substituant ces bouchons activés par des bouchons portants des groupements post-fonctionnalisables, puis en greffant des groupements cyanobiphényles. / Analogues of cyclotriveratrylenes and calix[n]arenes, pillar[n]arenes are composed of 1,4-disubstituted hydroquinone subunits linked by methylene bridges in their para positions. This macrocyclic core has been used as a compact scaffold for the preparation of nanomaterials. In this context, the chemical modification of the methylene bridge has been achieved to further functionalize the core in a way never explored so far. Firstly, oxidation of this position followed by Colvin reaction generated a strained triple bond in the macrocyclic scaffold. This particularity allowed the introduction of functional groups under copper free Huisgen 1,3-dipolar cycloadditions as well as by thermal [2+2] cycloadditions normally prohibited. Insertion of [60]fullerene on the methylene bridge has been also carried out. In a second time, photoactive [2]rotaxanes have been obtained from this fulleropillar[5]arene. Finally, a new methodology for the preparation of [2]rotaxanes has been developed. By exchange of activated stoppers, various [2]rotaxanes were thus obtained and this method is not limited by the nature of the stopper. This methodology has been used to prepare new liquid crystalline rotaxane derivatives by introduction of clickable stoppers followed by the grafting of dendritic mesogenic subunits.

La synthèse de phosphines secondaires borane dérivées d’aminoacides ou de dipeptides, et leur application pour la préparation de ligands ou le greffage du fullerène, est décrite. Elle se fait sans racémisation avec des rendements atteignant 98%, par alkylation de phosphines borane primaires avec un dérivé γ-iodo aminoacide, dans les conditions de transfert de phase. Les diphosphines tertiaires dérivées d’aminoacides, obtenues après une seconde alkylation avec des rendements atteignant 70%, sont parmi les premiers exemples de diphosphines greffées par une liaison P-C sur la chaine latérale d’un aminoacide. Les mono et diphosphines dérivées d’aminoacides ont été testées en catalyse d’allylation ou d’hydrogénation asymétriques catalysées par des complexes de palladium ou de rhodium. D’un autre côté, un complexe de cis platine a été préparé à partir d'une diphosphine dérivée d'un aminoester. Ses propriétés cytotoxiques ont été testées sur des lignées cellulaires ovariennes cancéreuses A2780. Dans une seconde partie les phosphines secondaires borane d’aminoacides et de peptides ont été utilisées pour le greffage du fullerène, par hydrophosphination en transfert de phase. L’étude électrochimique du dérivé fullerène d’aminoester de benzyle, a permis d’établir que ce composé se décomposait par électrolyse, avec coupure de la liaison P-C, pour libérer le fullerène et la phosphine secondaire borane aminoester. Ces travaux ouvrent de nouvelles perspectives pour la chimie des dérivés phosphines ou fullerène d'aminoacides et de peptides. / The synthesis of secondary phosphine borane amino acids or dipeptides and their applications for the preparation of chiral ligands or for the grafting of fullerene, is described. These compounds were synthesized in good yield (up to 98%) without racemization. The principle of the synthesis is based on the alkylation of primary phosphine borane with a γ-iodo amino acid using phase transfer conditions. Tertiary diphosphine amino acids are obtained with 70% yield after a second alkylation. These compounds are one of the first examples of diphosphine grafted with a P-C bond on the side chain of amino acid. First of all, mono and diphosphine amino acid derivatives were used in asymmetric allylic substitution with palladium precursor or in asymmetric hydrogenation with rhodium precursor. In another hand, a cis platinum complex was synthesized with 60% yield from the diphosphine amino acid derivative. The cytotoxic properties of this complex were tested against human ovarian carcinogenic cell lines A2780. In the second part, the secondary phosphine borane amino acids and peptides have been used for grafting fullerene C60 by hydrophosphination using phase transfer conditions. The electrochemical study of the fullerene amino benzyl ester derivative has shown the cleavage of the P-C60 bond by electrolysis, affording the free fullerene and the secondary phosphine borane amino ester moiety. This work opens new perspectives for the chemistry of fullerene and phosphine derivatives of amino acids and peptides.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第17539号 / 工博第3698号 / 新制||工||1563(附属図書館) / 30305 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 田中 宏明, 教授 米田 稔, 教授 伊藤 禎彦 / 学位規則第4条第1項該当

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-19T14:05:14Z No. of bitstreams: 1 marcelomoreiragoulart.pdf: 10308658 bytes, checksum: f8584bc8a12f11d188a8cdb968acd85d (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T17:58:35Z (GMT) No. of bitstreams: 1 marcelomoreiragoulart.pdf: 10308658 bytes, checksum: f8584bc8a12f11d188a8cdb968acd85d (MD5) / Made available in DSpace on 2016-01-25T17:58:35Z (GMT). No. of bitstreams: 1 marcelomoreiragoulart.pdf: 10308658 bytes, checksum: f8584bc8a12f11d188a8cdb968acd85d (MD5) Previous issue date: 2014-10-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Alcoóis e fulerenos estão entre as espécies atualmente observadas no meio interestelar (MI). Metanol é, dentre as espécies encontradas no espaço, uma das mais estudadas e sua importância como molécula orgânica é bem conhecida. A molécula de fulereno (carbono 60) pode ser responsável por carrear compostos entre diferentes regiões do espaço e pode, também, servir como matriz de reação para moléculas orgânicas tais como alcoóis. A investigação de possíveis reações químicas envolvendo diferentes compostos no MI pode auxiliar a compreensão a respeito da formação e transporte de moléculas no universo. Neste tese foram realizados experimentos nos quais aglomerados puros de metanol, etanol e também aglomerados de C60 dopados com estes alcoóis foram formados a partir da captura individual de moléculas por gotículas de He superfluido com temperatura isotérmica de 0,37 K atingida através de resfriamento evaporativo de átomos de Hélio (He). Após a captura os aglomerados foram ionizados por um feixe de elétrons de 70 eV e acelerados através de um conjunto de lentes eletrostáticas em direção a um analizador por tempo de vôo (TOF) onde o rendimento iônico foi obtido como função da razão massa sobre carga. Cálculos de mecânica molecular com a utilização do campo de forças MM2 e também simulações utilizando dinâmica molecular foram realizadas para interpretar os espectros obtidos. Nesta tese reportamos uma reação química ocorrendo no interior dos aglomerados após o processo de ionização, onde as moléculas de álcool sofrem desidratação, formando água (H2O), éteres dimetílico e dietílico e possivelmente eteno. Há evidências de que a reação é iniciada por um próton advindo da fragmentação de uma das moléculas alcoólicas devido ao processo de ionização. As moléculas de éter tendem a deixar o aglomerado após sua formação enquanto as moléculas de água permanecem no interior, solvatadas por alcoóis. Números mágicos são também observados nos espectros para diferentes números de moléculas de C60 e alcoóis. / Alcohols and fullerenes are among the species observed in the interstellar medium (ISM) to date. Methanol is one of the most studied molecules detected in space and its importance as an organic molecule is well known. The fullerene molecule (carbon 60) could be responsible for carrying compounds along different regions of space and could also serve as a reaction matrix for organic molecules such as alcohols. The investigation of the possible chemical reactions of different compounds in ISM could help to understand the formation and transport of molecules around the universe. In this thesis experiments were performed where pure methanol and etanol clusters as well as C60 clusters doped with those alcohols were formed upon pickup of individual molecules by superfluid He nanodroplets with an isothermic temperature of 0.37 K achieved by evaporative cooling of Helium (He) atoms. After pickup, the clusters were ionized by a 70 eV electron beam and then accelerated through a set of electrostatic lenses to a time-of-flight (TOF) analyzer, where the ion yield was recorded as a function of the mass to charge ratio. Molecular mechanics calculations with the MM2 force field as well as molecular dinamics simulations were performed to interpretate the spectra. Herein we report a chemical reaction occurring within the doped clusters upon ionization, where the alcohol molecules dehydrate forming water (H2O), dimethyl or diethyl ethers and also possibly ethene. There is evidence that the reaction is triggered by a proton coming from the fragmentation of one of the alcohol molecules due to the ionization process. The product ethers tend to leave the cluster after their formation while the H2O remains inside, solvated by alcohols. Magic numbers are also observed at the spectra for different number of C60 and alcohol molecules.

Dans ce travail de thèse, nous avons d'abord développé deux études basées sur des unités dites ''stilbène rigide'' qui sont connues pour s'interconvertir de manière réversible entre deux formes trans et cis grâce à la lumière. La première étude correspond à des photocommutateurs chiraux à base d'hélicènes, l'autre à des complexes photocommutables alcynyles d'or(I). Ensuite, nous avons examiné la synthèse et la caractérisation de complexes de Dy(III) à base d'hélicène-bipyridine comme nouveaux types d'aimants moléculaires (SMM) chiraux et comparé la différence des propriétés magnétiques entre les SMM racémique et énantiopurs. Enfin, nous avons développé la première utilisation de la cycloaddition réversible d'hélicènes racémiques sur le [60]fullerène et de sa rétrocycloaddition ultérieure comme une stratégie alternative efficace pour le dédoublement énantiomérique d'un hélicène-carboxaldéhyde. / In this PhD work, we firstly developed two studies based on the so-called ''stiff stilbene'' units that are known to reversibly interconvert between two trans and cis forms through light. The first study corresponds to photoresponsive chiral switches based on helicenes, the other one to photoresponsive gold(I) complexes. Then, we dealt with the synthesis and characterization of helicene-bipyridine based Dy(III) complexes as novel kinds of chiral single molecule magnets (SMMs) and compared the difference of the magnetic properties between racemic and enantiopure SMMs. Finally, we developed the first use of the reversible sterodivergent cycloaddition of racemic helicenes onto [60]fullerene with its subsequent retro-cycloaddition as an efficient alternative strategy for the enantiomeric resolution of a helicene-carboxaldehyde.

Die Herstellung von Kompositschichten aus unterschiedlichen Materialien mit verbesserten Schichteigenschaften stellt einen in den letzten Jahren intensiv erforschten Bereich der Dünnschichttechnik dar. Eine Methode zur Präparation solcher Kompositschichten besteht darin, Nano- oder Mikropartikel in eine Matrix aus einem anderen Material einzubringen. In der vorliegenden Arbeit werden so bis zu einige Mikrometer dicke Kompositschichten untersucht, die mit einem Sol-Gel-Verfahren hergestellt wurden und die bis zu 30 Gew.-% Wolframdisulfid-Partikel enthalten, welche als anorganische Fullerene typische Teilchengrößen von etwa 100 nm bis 200 nm aufweisen. Zwei unterschiedliche Arten an Kompositschichten mit eingebetteten Partikeln aus Wolframdisulfid werden hergestellt: Zum einen Schichten mit einer deutlich steiferen Matrix aus Aluminiumoxid und zum anderen Schichten mit einer Matrix aus organisch modifiziertem Siliziumoxid. Die strukturelle Charakterisierung der Schichten erfolgt über verschiedene analytische Verfahren. So werden die Kristallstruktur und chemische Zusammensetzung der Schichten mit Hilfe von Röntgenbeugungs- und Röntgenfluoreszenzmessungen sowie energiedispersiver Röntgenspektroskopie ermittelt. Raster- und Transmissionselektronenmikroskopie werden verwendet, um Aufschluss über die Verteilung der Wolframdisulfid-Partikel und ihren Einschluss in die jeweilige Matrix zu erhalten. Weiterhin werden die Rauheit und das Versagen der Schichthaftung auf dem Substrat untersucht. Der Einfluss der inkorporierten Partikel sowie der Herstellungstemperatur der Proben auf die mechanischen Eigenschaften der Kompositschichten wie Härte und E-Modul werden experimentell mit Nanoindentationsmessungen sowie theoretisch mittels verschiedener Modelle für effektive Materialien ermittelt. Schließlich erfolgt eine Charakterisierung der tribologischen Eigenschaften der Kompositschichten im Vergleich zu undotierten Schichten aus Aluminiumoxid oder organisch modifiziertem Siliziumoxid. Mit Hilfe einer Kugel-Scheibe-Geometrie wird der Reibkoeffizient der Schichten unter verschiedenen Bedingungen gemessen. Dabei zeigt sich, dass bei ausreichender Menge des eingeschlossenen Wolframdisulfids ein reibungsmindernder Effekt auftritt, was vielversprechend für eine mögliche Anwendung solcher Kompositschichten ist. / The preparation of composite coatings consisting of different materials with improved properties has been an intensively studied area of thin film technology in recent years. One method to prepare such composite coatings is the incorporation of nano or micro particles into a matrix of a different material. In this thesis, such composite coatings are investigated which have been prepared via a sol-gel route und contain up to about 30 wt.-% tungsten disulfide particles. These inorganic fullerenes have typical particle sizes of about 100 nm to 200 nm. Two different types of composite coatings with a thickness of up to a few micrometers and with embedded tungsten disulfide particles are prepared: First, coatings with a relatively stiff alumina matrix, and second, coatings with a matrix made of organically modified silica. Different analytical methods are used for the structural characterization of the coatings. The crystal structure and the chemical composition of the coatings are determined via x-ray diffraction and x-ray fluorescence measurements and via energy-dispersive x-ray spectroscopy. Through scanning and transmission electron microscopy the incorporation and the distribution of the tungsten disulfide particles in the respective matrix are analysed. Furthermore, the roughness and the adhesion of the coatings on the substrate are investigated. The influence of the embedded particles and of the temperature of the final heat treatment during the sample preparation on the mechanical properties, like elastic modulus and hardness, of the composite coatings are measured through nanoindentation testing. These experimental results are compared with theoretical values determined via different analytical models for effective materials. Finally, the tribological behavior of the composite coatings is investigated in comparison to pure coatings made of alumina or organically modified silica. With ball-on-disc tests the coefficient of friction of the coatings is measured under different conditions. It can be seen that the incorporation of a sufficiently high amount of tungsten disulfide leads to a strong reduction of friction, which is promising for a possible application of such composite coatings.