Dissertations / Theses on the topic 'C60'

Ce travail est consacre a l'etude des proprietes electrochimiques des electrodes composites a base de fullerenes (c#6#0, c#7#0 et le melange c#6#0/c#7#0). Deux milieux electrolytique differents sont utilises: electrolyte liquide organique et electrolyte polymere solide. L'oxydation du melange c#6#0/c#7#0 et du c70 pur en milieu liquide conduit probablement a la formation des composes du type c#6#0/c#7#0x#x et c#7#0x#x qui pourraient etre obtenus par un mecanisme de transfert de charge. Le taux d'insertion maximal theorique depend en particulier du type de l'anion (x#-). L'oxydation du c#6#0 pur ne presente aucun pic de courant anodique. Les methodes de caracterisation des produits d'insertion ne permettent pas a priori de confirmer les resultats obtenus electrochimiquement, ceci est du en grande partie a l'heterogeneite de l'electrode composite (c#6#0/poe/na). Dans le cas du c#7#0, la presence d'une couronne supplementaire d'hexagones a pour effet d'augmenter le caractere aromatique de la molecule et favoriser ainsi la delocalisation des electrons. Les especes anioniques de c#x#-#6#0 avec x>3, formees lors de la reduction cathodique des fullerenes se solubilisent au contact de l'electrolyte liquide ou solide. La reversibilite du systeme c#x#-#6#0/c#(#x#+#1#)#. #6#0 est profondement affectee par le choix de la nature du cation et de la limite de tension en polarisation cathodique. Dans la plupart des cas, le systeme est reversible dans une plage de tension comprise entre 1,5 v (cathodique) et 3 v (anodique), ce qui limite la quantite de l'espece cationique inseree dans le c#6#0. Les etudes cinetiques du c#6#0 en presence des cations alcalins montrent que le phenomene limitant la reaction d'insertion est la diffusion du cation m#+ dans le reseau cfc du c#6#0. Les performances des fullerenes fluores (c#6#0f#x) utilises comme electrode positive dans une batterie au lithium, sont faibles en comparaison avec le fluorure graphitique (cf#x). Ceci est probablement du au caractere covalent de la liaison c-f qui est plus marque dans c#6#0f#x. L'etude des proprietes electrochimiques des fullerenes purs ou modifies (c#6#0s#x, c#6#0h#x,), reste une voie de recherche tres prometteuse tant dans l'aspect fondamental qu'applique en particulier dans le stockage electrochimique de l'energie

The goal of this dissertation is to study the photophysics of suspensions of colloidal C₆₀ particles to determine if their nonlinear optical (NLO) response is superior in any way to benchmark NLO materials such as molecular solutions of C₆₀ and carbon black suspensions (CBS). C₆₀ in molecular form is known to exhibit strong reverse saturable absorption (RSA) and it is posited that colloidal particles composed of many C₆₀ molecules would maintain some degree of RSA behavior upon association, although some quenching is to be expected. CBS is known to have an NLO response that is dominated by nonlinear scattering resulting from a phase change due to heating of the carbon black particles by absorbed energy. Colloidal C₆₀ particles that are many nanometers in diameter are similar to CBS, so it is posited that they would also have a nonlinear scattering mechanism contributing to their NLO response. Three samples of C₆₀ colloids are characterized by several techniques, along with two carbon black suspensions and one molecular solution of C₆₀. Transmission electron microscopy is used to determine morphology. Femtosecond pump-probe spectroscopy is used to determine the absorption spectrum and the relaxation kinetics of the first excited singlet state. Nanosecond laser flash photolysis is used to determine the absorption spectrum and the relaxation kinetics of the first excited triplet state. Z-scan is used to determine triplet-triplet absorption cross-sections. An experiment is performed to determine the percentage of the input energy that is transmitted, scattered, or absorbed by each sample. Computer modeling is performed to compare the experimental results to theory. Results show that all materials that exhibit nonlinear scattering have a constant extinction coefficient in the nonlinear regime, implying a characteristic size for the scattering centers that is independent of input energy. Quenching processes in C₆₀ colloids are found to be morphology dependent, with more crystalline structures resulting in stronger quenching and less RSA. C₆₀ colloids with stronger RSA are found to result in less nonlinear scattering than strongly quenched colloids. Highly crystalline C₆₀ colloids were shown to have a stronger NLO response than the benchmark materials at medium to high energies.

L'influence de l'intercalation spontanee et forcee des couches minces de fullerenes c#6#0 et c#7#0 sur leurs proprietes electriques est etudiee. La methode de depot des couches minces par evaporation thermique de poudres est presentee. La reversibilite de l'intercalation spontanee de l'oxygene atmospherique dans les couches est demontree. Le taux de dopage du c#6#0 par le potassium est relie avec la resistivite des echantillons. La diffusion du metal des contacts electriques dans les couches, stimulee par le champ electrique, est discutee comme une nouvelle voie de dopage electrochimique des fullerenes

Le travail décrit dans cette thèse vise à produire des nanostructures bien ordonnées présentant une forte activité catalytique sur la base d’ensembles de nanoparticules de ruthénium et de fullerènes/fullerènes fonctionnalisés. Le Chapitre 1 présente une analyse bibliographique sur l’utilisation des fullerènes en catalyse hétérogène, en mettant en avant leurs propriétés particulières telles que la stabilité thermique, une grande capacité d'adsorption d'hydrogène et la capacité d’obtenir diverses coordinations. Le Chapitre 2 décrit la synthèse et la caractérisation de nanostructures Ru@C60 obtenues par la réaction de décomposition par au dihydrogène du complexe [Ru(COD)(COT)] en présence de C60. L'effet du solvant et des rapports de Ru/C60 utilisés durant la réaction ont été étudiés. Plusieurs caractérisations d’objets sphériques Ru@C60 et des calculs DFT nous permettent de proposer une voie pour leur formation. Le Chapitre 3 présente la préparation de nouveaux nano-assemblages obtenus à partir de [Ru(COD)(COT)] et de fullerènes fonctionnalisés en utilisant la même méthode décrite dans le chapitre 2. Tout d'abord la synthèse de fullerènes fonctionnalisés C66(COOH)12 est détaillée, puis la synthèse et la caractérisation des nanostructures Ru@C66(COOH)12 ont été étudiés. Le Chapitre 4 décrit l'utilisation de ces nanomatériaux en catalyse. Nous avons préparé trois Ru@fullerene: Ru@C60 dans du dichlorométhane, T-Ru@C60 dans le toluène et Ru@C66(COOH)12. Ensuite, l'activité catalytique et la sélectivité des catalyseurs préparés Ru@C60, T-Ru@C60 et Ru@C66(COOH)12 ont été étudiées pour l'hydrogénation du nitrobenzène et du cinnamaldéhyde. Des calculs DFT ont permis de rationaliser les résultats obtenus pour l'hydrogénation sélective de nitrobenzène sur Ru@C60
The work described in this thesis aims to produce well-ordered nanostructures presenting high catalytic activity, on the bases of the assembly of ruthenium nanoparticles and fullerene/functionalized fullerene. Chapter 1 provides a review on the use of fullerene and fullerene-based materials in heterogeneous catalysis, emphasizing their specific properties such as thermal stability, high capacity for hydrogen adsorption and the ability of various coordination modes. Chapter 2 describes the synthesis and characterization of Ru@C60 nanostructures produced by the decomposition reaction of [Ru(COD)(COT)] in the presence of C60. The effect of the solvent and ratios of Ru/C60 on the course of the reaction have been investigated. Several characterizations of spherical Ru@C60 objects and DFT calculations allow us to propose a pathway for their formation. Chapter 3 presents new nano-assembly preparation based on [Ru(COD)(COT)] and functionalized fullerene using the same method as they are described in chapter 2. First, the synthesis of functionalized fullerene C66(COOH)12 is detailed, and then the synthesis and characterization of Ru@C66(COOH)12 is studied. Chapter 4 describes the use of these nanomaterials in catalysis. We have prepared three Ru@fullerene catalysts, which are Ru@C60 in dichloromethane, T-Ru@C60 in toluene, and Ru@C66(COOH)12. Then, the catalytic activity and selectivity of the prepared catalyst Ru@C60, T-Ru@C60 and Ru@C66(COOH)12 are studied for the hydrogenation of nitrobenzene and cinnamaldehyde. DFT calculations allow to rationalize the results obtained for the selective hydrogenation of nitrobenzene over Ru@C60

Nous avons mis au point un appareillage pour la synthese des fullerenes par la methode de l'arc electrique. Les fullerenes c60 et c70 sont caracterises par rmn, par spectroscopies de masse ir et raman. Nous decrivons aussi un dispositif de preparation de couches minces de fullerenes. Nous nous sommes interesses a l'origine de la largeur residuelle de la raie unique de resonance (rmn #1#3c) de c60. Le temps de relaxation tl de cette raie a ete aussi etudie en fonction de la temperature. Les systemes axc60 et axc60/c70 (a=rb, x et x:3) ont ete etudiees par rmn et raman. Le deplacement de la resonance dans ces systemes est interprete en termes de knight. Tl est interprete par la loi de korringa. Le deplacement du mode elastique de vibration (actif en raman) de la double liaison c=c a ete discute comme fonction du degre de transfert de charge entre le dopant et le c60

This thesis focuses on the thermodynamic and crystallographic characterization of C60 solvates formed with small organic molecules (CBr2(CH3)2, CBr2Cl2, CBr2H2, CBrCl2H and CBrClH2) Chapter I provides an introduction concerning the physical and chemical properties of fullerene C60 as well as the state of the art for solvates or co-crystals formed between C60 and organic materials. Chapter II provides information about experimental techniques and models used for the acquisition and analyses of experimental data. The analysis and discussion of the obtained results are presented in the following five chapters, one for each organic solvent under scrutiny. The last chapter is devoted to overall conclusions concerning the structural and thermodynamic common properties of the studied solvates. In Chapter III, the stable monoclinic solvate C60·2CBr2H2, has been structurally and thermodynamically characterized. It exhibits overall orientational order due to strong interactions between C60 and solvent host molecule. The orientational order is consistent with the stability found as well as with the high negative excess volume and a high desolvation enthalpy. Chapter IV deals with cubic co-crystals of C60·12CBr2(CH3)2, with C2v molecular symmetry. The cubic co-crystals are found to be unstable in air and transform spontaneously into hexagonal co-crystals C60·2CBr2(CH3)2, in which solvent molecules (orientationally disordered) are located close to the prismatic hexagonal voids of the structure. Chapter V describes the cubic co-crystals of C60·12CCl2Br2, also unstable in air. Co-crystals transform spontaneously into the hexagonal co-crystals C60·2CCl2Br2 (formed with negative excess volume) in which the solvent molecules (C2v symmetry) are orientationally disordered and are located close to the prismatic hexagonal voids. In Chapter VI, the in air stable solvate C60·2CBrCl2H is described. The solvent molecules, with C3v pseudo-symmetry (if one consider the halogen Br and Cl being interchangeable). The hexagonal solvate undergoes a transformation on heating to another solvate of lower stoichiometry C60·CBrCl2H with a monoclinic structure. Paradoxically, the measured desolvation enthalpies for both C60·2CBrCl2H and C60·CBrCl2H do not exceed the sublimation enthalpy of pure CBrCl2H. Chapter VII is devoted to the characterization of the monoclinic solvate C60·2CBrClH2. This low-temperature solvate transforms reversibly on heating to an hexagonal structure with the same stoichiometry. Both co-crystal structures form with a negative excess volume indicating strong intermolecular interactions between the C60 and CBrCl2H. This result is in clear contradiction to the determined desolvation enthalpy, clearly smaller than the sublimation enthalpies of the involved solvent. The last chapter VIII, put together overall experimental results in order to derive common properties for the different studied solvates. To do so, the results of this thesis are analyzed in combination with previous reported results for molecular solvates for which the solvent molecules have strong similarities to those studied in this work. Thus, we present a tentative overview of crystallographic and thermodynamic results obtained in the frame of a systematic investigation on C60:Solvent solvates. The results of this thesis represent an step forward in the direction of extending the current experimental knowledge of co-crystals of C60:Solvents. Moreover, the work makes a proposal in order to rationalize the structural properties of these solvates, which mainly consists of a prediction of the solvate volumes according to the van der Waals volumes of the involved chemical species.
El objetivo de esta tesis es la caracterización termodinámica y cristalográfica de solvatos de C60 formados con moléculas orgánicas de pequeño tamaño (CBr2(CH3)2, CBr2Cl2, CBr2H2, CBrCl2H y CBrClH2). En el capítulo I se realiza una introducción a las propiedades físicas y químicas del fulereno C60 así como una breve revisión de los trabajos que se han publicado de compuestos formados entre C60 y materiales orgánicos. Las técnicas experimentales empleadas para la adquisición de los datos juntamente con los modelos empleados para su análisis. El análisis y discusión de los resultados se presentan en los siguientes cinco capítulos, uno para cada uno de los sistemas binarios C60:disolvente analizados. En el último capítulo se presentan las conclusiones del trabajo estableciéndose un análisis de las propiedades estructurales y termodinámicas del conjunto de sistemas estudiados. En el capítulo III se ha caracterizado el solvatoC60· 2CBr2H2 de estructura monoclínica en el que tanto las moléculas de disolvente como el C60 presentan orden orientacional. La existencia de fuertes interacciones entre ambas moléculas genera un volumen de exceso negativo así como una elevada entalpía de desolvatación coherentes con la estabilidad del solvato. En el capítulo IV se ha caracterizado el solvato cúbico C60·12CBr2(CH3)2 que es inestable fuera de la solución y transforma espontáneamente en el solvato hexagonal C60·2CBr2(CH3)2en el que las molècules constituyentes están desordenadas orientacionalmente. Las moléculas de solvente ocupan los huecos intersticiales dejados por las moléculas de C60 en su empaquetamiento hexagonal. En el capítulo V se describen los solvatos formados entre el C60 y el disolvente CCl2Br2. Este sistema presenta 2 solvatos , C60·12CCl2Br2 de simetría cúbica inestable en aire y C60·2CCl2Br2 de simetría hexagonal formado con un volumen de exceso negativo. En el capítulo VI se describe el solvato estable C60·2CBrCl2H de simetría hexagonal en el que las moléculas de disolvente pueden simular una pseudo simetría C3v mediante el intercambio de los dos halógenos. Calentando este solvato este transforma en otro de más baja estequiometria C60·CBrCl2H también estable de estructura monoclínica. Paradójicamente, las entalpías de desolvatación de ambos solvatos no superan la entalpía de sublimación del disolvente puro. En el capítulo VI se describe el solvato estable C60·2CBrCl2H. Este solvato de simetría monoclínica transforma reversiblemente a alta temperatura a una fase hexagonal con la misma estequiometria. Ambas estructuras son formadas con volúmenes de exceso negativos lo que indica fuertes interacciones entre las moléculas de C60 y el disolvente. Por el contrario la entalpía de desolvatación no supera la entalpía de sublimación del disolvente. En el último capítulo se analizan los resultados experimentales obtenidos en los solvatos estudiados conjuntamente con resultados publicados previamente para solvatos formados con moléculas de características similares a las estudiadas en este trabajo. Esto permite establecer una serie de correlaciones termodinámicas y cristalográficas de mayor generalidad en este conjunto de solvatos. Los resultados de esta tesis representan una contribución en el estudio del comportamiento experimental de los co-cristales de C60: Disolventes. Además, el trabajo realiza una propuesta con el fin de racionalizar las propiedades estructurales de estos solvatos, que principalmente consiste en una predicción de los volúmenes de solvato de acuerdo con los volúmenes de van der Waals de las especies químicas involucradas.

Kinetics and pathways of C60 reaction with hydrogen gas were studied in a broad temperature interval and over extended periods of time. Specifically, hydrogenation was monitored in situ at high temperature and high hydrogen pressure conditions using gravimetric method. The shape of gravimetric curve was found to depend on hydrogena tion temperature: at 350-400ºC saturation of the sample weight was achieved, whereas at 420-440ºC the sample weight reached the maximum and decreased upon prolonged hydrogenation. The weight decrease is due to fullerene cage fragmentation with formation of light ydrocarbons evaporating from the sample. Hydrogenation products were studied by X-ray diffraction, APPI FT-ICR mass spectrometry, and elemental analysis. Hydrogenation pathways (from C60H18 up to C60H56) and possible mechanisms of hydrogenation-induced fragmentation of fulleranes are discussed. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20618

This work is a pioneer study on the role played by molecular interfaces in altering the electronic states of non-ferromagnetic materials. Here, we consider diamagnetic copper and paramagnetic manganese and scandium, to overcome the Stoner criterion and make them magnetically ordered at room temperature. The mechanism is mediated by the charge transfer from the transition metal and hybridization with molecular carbon, creating new 3d-π that drastically modify the electron energy bands around the Fermi energy of both metal and molecule. This effect is achieved via interfaces between metallic thin films and C60 molecular layers. The emergent spin ordering arising in these systems is measured using magnetometry shows magnetically ordered behaviour at room temperature, but dependent on the thickness and continuity of the metallic layer. To determine how in the layered structure the emergent spin ordering is distributed, low-energy muon spin spectroscopy is utilised by studying the depolarization process of low-energy muons implanted in the sample. This technique indicates localised spin-ordered states at, and close to, the metallo-molecular interface. X-ray absorption spectroscopy provides an excellent tool for identifying the emergent spin ordering of specific elements within a sample. The change in the molecular orbitals of C60 due to charge transfer and 3d-π hybridization is evaluated based on this technique. The presence of spin ordering in a non-magnetic metallic host due to molecular charge transfer has a drastic effect not only on the magnetic but also on the transport properties of the system. The decisive role of the molecular interfaces in the physics of spin dependent scattering within a non-magnetic host has been demonstrated. Localised spin ordering leads to changes in the Kondo and weak localisation effects with applications in low temperature thermometry and quantum devices. It is found that there is an additional magnetic scattering that has a pronounced contribution when C60 molecules are embedded into the non-magnetic Cu and hence creates localised spins. The localised spin ordering that emerged at molecular interfaces is a new approach for novel generation of materials for future spintronics devices.

Presently, C60 fullerene and its derivatives are of great importance in chemistry, mainly due to their physical properties and biological activities. One of the main problems related to C60 is its low solubility in the commonly used solvents, which limits its application. Aiming to study their physicochemical properties, 17 new C60 derivatives with appropriate solubility were synthesized in this work through a cyclopropranation reaction and functionalized with carbohydrates, pyridines, tetrazoles, and oxadiazole. Considering that the azole derivatives presented good solubility in organic solvents and aiming for a possible application of these compounds, two studies of their physico-chemical properties were performed: the investigation of the photosensibility of these derivatives in solution and the study of their electrochemical properties. The photosensibility for conversion of oxygen triplets into reactive oxygen species (ROS) was investigated by electron paramagnetic resonance. The results suggest that ROS were produced in an azole derivative solution under laser illumination. These derivatives, therefore, are potential photosensitizers and may have a topical use in photodynamic therapy. The analysis of the azole derivatives by cyclic voltammetry has shown that the electrochemical properties of the C60 sphere were not significantly altered by its functionalization. Therefore, these derivatives are promising candidates for the construction of a photovoltaic cell. The pyridinium salts and the synthesized tetrazole salts presented good solubility in DMSO and in a mixture of DMSO/H2O, which makes the future investigation of the biological and photophysical properties of their compounds possible. On the other hand, the insolubility of carbohydrate-containing fullerene derivatives is an obstacle to their practical application.
O fulereno C60 e seus derivados são de grande importância na química atual, principalmente devido às propriedades físicas e atividades biológicas relatadas para estes compostos. Um dos principais problemas relacionados ao C60 é a sua baixa solubilidade em solventes usuais, o que limita a aplicação deste composto. Visando sintetizar derivados fulerênicos com solubilidade adequada para estudar suas propriedades físico-químicas foram sintetizados neste trabalho, por meio da reação de ciclopropanação, 17 novos derivados do C60, funcionalizados com carboidratos, piridinas, tetrazóis e oxadiazol. Considerando que os derivados azólicos, apresentaram boa solubilidade em solventes orgânicos e, visando uma possível aplicação destes compostos, foram realizados dois estudos de suas propriedades físico-químicas: a investigação da fotossensibilidade destes derivados em solução e o estudo de suas propriedades eletroquímicas. A fotossensibilidade para a conversão de oxigênio tripleto em espécies reativas de oxigênio foi realizada por Ressonância Paramagnética Eletrônica. Os resultados sugerem que espécies reativas de oxigênio estão sendo produzidas nas soluções dos derivados azólicos, sob iluminação com laser. Com isso, estes derivados apresentaram-se como potenciais fotossensibilizadores, podendo ser utilizados para uso tópico em terapia fotodinâmica. A análise dos derivados azólicos por voltametria cíclica mostrou que a propriedade eletroquímica da esfera do C60 não foi alterada significativamente após sua funcionalização. Com isso pode-se considerar que estes derivados são promissores candidatos para construção de uma célula fotovoltaica. Os sais de piridínio e de tetrazol sintetizados, apresentaram boa solubilidade em DMSO e em uma mistura de DMSO/H2O o que torna possível avaliar futuramente as propriedades biológicas e fotofísicas destes compostos. Já a insolubilidade dos derivados fulerênicos contendo carboidratos representou um obstáculo para as suas aplicações práticas.

Since its discovery in 1985, buckminsterfullerene (C ₆₀) has been extensively studied due to its unique properties and it's now being produced in multi-ton quantities. The ability to form stable aqueous C₆₀ colloids (known as nano-C₆₀ or nC ₆₀) and the availability of these in natural systems at environmentally-relevant concentrations led to significant interest concerning the environmental health and safety of these colloidal aggregates. Addressing two issues with regard to this material's environmental health and safety concerns we have looked at the oxidative mechanism of these nC₆₀ colloidal aggregates and their thermal stability. For making accurate kinetics and measurements on oxidation caused by aqueous-nC₆₀ colloidal dispersions, we have developed experimental methods utilizing dihydrorhodamine 123 (DHR123) as a sacrificial probe molecule to monitor oxidation by fluorescence spectroscopy and kinetic models to explain observed oxidation. Evaluation of the oxidative behavior of fullerene colloids has been determined using the oxidation rate as a function of nC₆₀ concentration, nC₆₀ surface area, number of colloidal particles and C ₆₀O content, operating where necessary under inert atmosphere and oxygen rich conditions. The effect of temperature on these colloids plays a significant role in both their synthesis and reactivity. Given that the colloids are mainly composed of C₆₀ and C₆₀O, C₆₀O might play a significant role in stabilizing the colloid, hence increasing the temperature might cause thermally-activated reactions with C₆₀O. Thermal stability of these colloids prepared by all four primary nC₆₀ synthesis methods has been investigated. Incorporation of C₆₀ into polymers is of potential interest for applications, for sequestration to address potential environmental health and safety issues, and as a component in novel architectures. A new composite material was developed by encapsulating C₆₀ into cross-linked polymer network formed by γ-cyclodextrin. A simple synthesis route to achieve composite membranes of intercalated C ₆₀ in the polymer network is presented.

Orientador: Marlus Koehler
Tese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Curso de Pós-Graduação em Física. Defesa: Curitiba, 17/02/2016
Inclui referências : f. 130-141
Resumo: A energia solar é a fonte de energia mais abundante e é a que nos proporciona uma fonte limpa e renovável. As pesquisas atuais estão voltadas para a captação e conversão dessa fonte de energia em energia elétrica. No entanto, os dispositivos capazes de realizar essa captação e produção são a base de silício, que além de apresentar custo elevado é ainda de baixa eficiência. Nosso trabalho vem ao encontro das pesquisas que buscam outros materiais capazes de captar e transformar a energia solar em elétrica, sempre no intuito de buscar eficiência e custo. Aqui, através dos métodos TFD (Teoria do Funcional Densidade) e TDFTB (Teoria do Funcional Densidade baseado em Tight Binding), fizemos simulações para realizarmos uma análise teórica da estrutura eletrônica dos fulerenos C60 e C70 bem como do polímero P3HT e nanofitas de carbono passivadas com átomos de hidrogênios e oxidada com com o grupo químico -OH, com o objetivo de analisarmos a possibilidade dessas estruturas serem possíveis candidatas a materiais componentes de dispositivos fotovoltaicos. Das interações analisadas, mostramos que, teoricamente, a interação mais favorável a uma transferência de carga elementar se dá entre o C70 interagindo com a nanofita oxidada. Palavras chave: fulerenos, nanofitas de grafeno, P3HT, célula solar orgânica.
Abstract: The solar energy is the most abundant source of energy and is the one that gives us a clean and renewable alternative. Current researches are focused on to capture and to transform this form of energy into electrical energy. However, devices capable of performing this uptake and prouction are siliconbased, which besides presenting high cost, still has low eficiency. As other scientific researches, at this work, we seek for materials able to capture and transform solar energy into electricity, in order to optimize efficiency and reduce costs. We used DFT (Density Functional Theory) and DFTB (Density Functional based Tight Binding) methods to perform simulations and investigate the theoretical behavior of the electronic structure of fullerenes C60 and C70, of the polymer P3HT and of the passivated carbon nanoribbons with atoms oxidized and protons with the chemical -OH. We aimed to analyze the possibility of using this structures as candidates for materials component in photovoltaic devices. From our theoretical studies we observed a favorable interaction to an elementary charge transfer between the C70, when it is in interaction with the oxidized nanoribbon. Key words: fullerene, nanoribbon, P3HT and sollar cells.

Correlated many-particle dynamics in Coulombic systems is one of today‟s grand challenges in physics. In order to address this task, the electronic structure and electron correlations of multiply ionised systems are studied in this thesis, aiming to obtain information on the dynamics of electron emission processes at unprecedented ease and high resolution. State-of-the-art multi-electron correlation spectrometers are used, which were originally developed at Oxford University, UK, and which are now frequently in use at the Ångström laboratory in Uppsala, Sweden.The research is so far based mainly on single-photon excitations using laboratory light sources and synchrotron radiation facilities, and expands now gradually into non-linear and time-resolved studies of atoms, molecules and clusters using high intensive Free Electron Lasers (FEL) in the Vacuum Ultra-Violet (VUV) and X-ray spectral region. This development is highly relevant for even more deep-going applications regarding the ion and excited-state balance in the Earth‟s outer atmosphere and in astrophysical contexts, for photochemistry and biochemistry, for materials science, and to test current atomic and molecular structure theories to their limits.We will focus on the multiple ionization of the buckminsterfullerene (C60) which is of scientific interest as an exceptionally stable and symmetric cluster. Its applications are quite large in nanotechnologies.

The solvent induced spectral shift method is applied to study stacking interactions between aromatic solvents molecules, such as benzene and toluene from one side, and solute fullerene C60. Ratios of high-energy transitions shifts to calculated shifts under dispersion interactions are considered. It is concluded that in contrast to aromatic molecules containing two or three rings which do not form complexes with aromatic solvents, fullerene forms exciplexes with high-energy excited states involved in more strong interactions rather than low-energy one. The higher is excited state, the stronger is interaction. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20624

The discovery that negatively charged aggregates of C60 fullerene are stable in aqueous environments has elicited concerns regarding the potential environmental and health effects of these aggregates. Although many previous studies have used aggregates synthesized using intermediate organic solvents, this work primarily employed an aggregate production method that more closely emulates the fate of C60 upon accidental release into the environment â extended mixing in water. The aggregates formed via this method (aqu/nC60) differ from those produced using the more common solvent exchange methods. The aqu/nC60 aggregates are heterogeneous in size (20 nm and larger) and shape (angular to round), negatively charged, and crystalline in structure â exhibiting a face centered cubic (fcc) system. Solution characteristics such as aqu/nC60 aggregate size and concentration were found to be dependant upon preparation variables such as stirring time, initial C60 concentration, and initial particle size. Additional experiments indicate that aggregate charge, structure, and stability are highly dependant upon the identity of co-solutes (NaCl, CaCl2, sodium citrate) and their concentrations. Citrate concentrations greater than 0.5 mM resulted in the formation of very small (< 20 nm) spherical aqu/nC60 particles. At moderate citrate concentrations (~ 1 mM) a more negative surface charge was observed, which may be an indication of increased nC60 stability. In contrast, high concentrations of monovalent and divalent electrolytes result in aggregation and sedimentation of nC60 out of solution. Our research describes the effect that solution composition has on aggregate formation and stability, and suggests that C60 fate and transport will be a function of solution composition.
Master of Science

Ce mémoire est consacré à l'étude du c60 sous pression. Le diagramme de phases pour le c60 a été établi pour des pressions inférieures à 80kbar. L'application de très hautes pressions (200kbar) à température ambiante transforme le c60 en carbone sp3 et en diamant. A plus basse pression et à haute température, le c60 est converti en carbone sp2 amorphe de type graphitique. Pour des pressions et des températures intermédiaires, trois nouvelles phases polymérisées du c60 ont été obtenues, la structure en cage y est conservée. La phase rhomboedrique et la phase quadratique sont des phases bi-dimensionnelles, la phase orthorhombique est une phase 1d. Dans toutes ces structures, les orientations moléculaires permettent la formation de liaisons intermoléculaires de type cycloaddition 2,2. La nature polymère de ces phases et le type de liaisons ont été obtenues par diffraction x, par calculs théoriques, puis confirmés par rmn solide et spectroscopie ir et raman. Nous suggérons aussi l'existence de polymères 3d à plus forte pression et températures. Leurs structures devraient correspondre à la formation de liaisons interplanaires entre les plans polymérisés

Mestrado em Ensino de Física e Química
Com a descoberta dos fullerenos e sobretudo, com a capacidade de sintetizá-los em grandes quantidades, nasce uma nova forma alotrópica do carbono cuja unidade estrutural mais abundante é a molécula de C60. A extrema estabilidade desta molécula é explicada pela elevada simetria da sua estrutura em forma de um icosaedro truncado. No estudo das propriedades físicas e químicas de substâncias elementares constituídas pelo mesmo elemento o exemplo do diamante e da grafite é já, tradicionalmente, utilizado e referenciado. É, sem dúvida, surpreendente e interpelativo o facto destes dois alótropos possuírem propriedades físicas tão contraditórias: a dureza, o brilho e a transparência do diamante contrapõem-se à moleza, à cor negra e à opacidade da grafite. A chegada da terceira forma alotrópica do carbono suscita uma enorme curiosidade em torno das propriedades dos cristais moleculares de C60 e da molécula em si, levando a uma inevitavelmente comparação com as propriedades e estrutura elementar dos outros alótropos do elemento carbono. O estudo desenvolvido teve como principal objectivo verificar se a substancia elementar C60 é passível de ser estudada em níveis de escolaridade não universitários. Neste sentido, desenvolveu-se um estudo teórico sobre as propriedades físicas e químicas que os cristais de C60 manifestam, nomeadamente, a sua supercondutividade e a reactividade química, as quais são realçadas pela importância das suas possíveis aplicações. Foi também realizado um estudo empírico comparativo das propriedades físicas dos cristais e de filmes de cada uma das três substâncias elementares de carbono, tendo sido utilizadas as instalações e o equipamento do Departamento de Física da Universidade de Aveiro, no ano lectivo 2000/2001. Os resultados obtidos permitiram concluir que é possível verificar nos níveis de ensino Básico e Secundário, as diferentes características que uma substância elementar pode assumir, nomeadamente, a morfologia e orientação dos cristais. O Estudo tem como primeiros destinatários professores de Física e Química (ensinos Básicos e Secundário) e considera-se que este estudo pode servir de base de trabalho para aqueles que pretendam fornecer aos seus alunos, como actividade de enriquecimento científico, e por isso mesmo cultural, noções fundamentais e actuais da Física e da Química.
With the discovery of fullerens and mainly, with the capacity of producing them in big quantities, a new allotropic form of carbon is born, in which the mostly abundant structural unit is the C60 molecule. The high stability of this molecule can be explained by the symmetry of its structure with the shape of a truncated icosahedron. In the study of physical and chemical properties of elementary substances formed by the same element, diamond and graphite are the most referred and traditionally given examples. The fact that these two allotropes have such contradictory physical properties: the hardness, the brightress and the transparency of diamond as oppose to the softness, to the black colour and to the opacity of graphite is undoubtedly amazing and interpellant. The arrival of the third allotropic form of carbon arises enormous curiosity around the properties of C60 molecular crystals and abount the molecule itself, leading to an inevitable comparison with the properties and elementary structure of other allotropes of the carbon element. The main aim of this study was to check if the elementary substance C60 can be studied in different nonuniversity school levels. Therefore, a theoretical study on the physical and chemical properties that C60 crystals presents, particularly its superconductivity and chemical reactivity which are highlighted by the importance of its possible applications, was conducted. Also an empirical study took place to compare the physical properties of crystals and films of each of the three elementary substances of carbon. This was done with the use of equipment from the Physics Department at the University of Aveiro, during the school year of 2000/2001. The results obtained lead to the conclusion that, it is possible in Elementary and Secondary school levels, to check the different characteristics which an elementary substance may assume, mainly the morphology and the orientation of the crystals. The study was oriented to Elementary and Secondary Physics and Chemistry School teachers, and it is believed that this study may be a basis of work for those who want to give their students fundamental and up-to-date notions of Physics and Chemistry, as an activity of scientific, and therefore, cultural enrichment.

Nos travaux antérieurs ont développé la débenzylation DIBAL-H de α-, β- et γ-CDBn, qui génère une fonctionnalisation regiosélective sur le bord primaire. De plus, la déméthylation DIBAL-H de α- et β-CDMe donne accès à une modification régiosélective sur le bord secondaire sans changer la conformation de l'unité suger. La déméthylation DIBAL-H optimisée pourrait également influer sur la modification du bord primaire. En raison de la grande cavité du γ-CD sur la solubilisation et l'encapsulation C60, l'un des objectifs de mon travail est d'obtenir le γ-CDMe sélectivement modifié sur le bord secondaire. Sur la base de la déméthylation DIBAL-H de α-, β- et γ-CDMe, 7 conjugués α-CD-C60 sont soumis à l'évaluation biologique en tant qu'agents antiviraux potentiels et un conjugué β-CD-C60 est en cours d'étude en tant que potentiel anti-allergique agent. En outre, le conjugué 2A-γ-CDMe-C60 avec attachement de jante secondaire présente la plus grande solubilité dans l'eau parmi les conjugués CD-C60 et les complexes γ-CD / C60. Le conjugué 2A-γ-CDMe-C60 et le conjugué 6A-γ-CDMe-C60 avec fixation du jonc primaire ont montré un rendement quantique 1O2 plus élevé que les conjugués CD-C60 rapportés sous irradiation UV. À la lumière de la méthodologie de la débenzylation DIBAL-H, 6 complexes α- et β-CDMe-Ag hydrosolubles (Cu, Au) ont été synthétisés. On a obtenu des structures cristallines à rayons X d'α-CDMe-AgCl à la fois dans CDCl3 et dans de l'eau. Par ailleurs, nous avons obtenu le monomère α-CDMe-CuCCPh qui est stable dans l'eau. De plus, α- et β-CDMe-AuCl ont été comme catalyseurs en cyclosomérisation regiosélective, énantiéselective et lactonisation dans DCM et eau
Our previous work have developed DIBAL-H debenzylation of α-, β- and γ-CDBn, which generates regioselective functionalization on the primary rim. Moreover, DIBAL-H demethylation of α- and β-CDMe gives an access to regioselective modification on the secondary rim without changing the conformation of suger unit. Meanwhile, the optimized DIBAL-H demethylation could affordes the modification on the primary rim as well. Because of the large cavity of γ-CD on C60 solubilization and encapsulation, one of the goals of my work is to obtain the selectively modified γ-CDMe on the secondary rim. Based on DIBAL-H demethylation of α-, β- and γ-CDMe, 7 α-CD-C60 conjugates are under the biological evaluation as potential antiviral agents and a β-CD-C60 conjugate is being studied as a potential anti-allergic agent. Furthermore, 2A-γ-CDMe-C60 conjugate with secondary rim attachement displays the highest water-solubility among CD-C60 conjugates and γ-CD/C60 complexes. Both 2A-γ-CDMe-C60 conjugate and 6A-γ-CDMe-C60 conjugate with primary rim attachment showed higher 1O2 quantume yield than the reported CD-C60 conjugates under UV irradiation. In light of the methodology of DIBAL-H debenzylation, 6 water-soluble α- and β-CDMe-Ag(Cu, Au) complexes have been synthesized. X-ray crystal structures of α-CDMe-AgCl in both CDCl3 and water have been obtained. Besides, we got monomer α-CDMe-CuCCPh which is stable in water. In addition, α- and β-CDMe-AuCl have been as catalysts in regioselective, enantioselective cycloisomerization and lactonization in DCM and neat water

Ce travail de thèse est consacré à l'étude des propriétés structurales et dynamiques, en fonction de la température et de la pression, des structures unidimensionnelles des fullerènes C60 et C70, respectivement de formes sphériques et ellipsoïdales, confinés dans les nanotubes de carbone. Ces nano-hybrides sont communément appelées peapods. La structure des peapods est étudiée à l'aide de la diffraction des rayons X et de la diffraction électronique. La simulation des diagrammes de diffraction permet de déterminer la structure des nanotubes de carbone (rayon moyen (0.7nm), distribution de rayons) ainsi que le taux de remplissage des nanotubes par les fullerènes et le paramètre de maille des chaînes de fullerènes. Dans le cas des peapods de C70, l'orientation des molécules en fonction du diamètre des nanotubes est analysée et la valeur du diamètre « critique » de changement d'orientation est déterminée. Les évolutions de la structure des chaînes de fullerènes (dilatation thermique, polymérisation, coalescence) en fonction de la température et/ou de la pression sont étudiées et comparées pour les deux sortes de fullerènes considérés. Des différences sont observées entre fullerènes C60 et C70 quant à la polymérisation à hautes pressions et températures. Les molécules de C60 polymérisent par cyclo-addition [2+2] dans les nanotubes, mais pas celles de C70, ce résultat étant expliqué par le confinement par le nanotube de carbone. La structure des nanotubes bifeuillets obtenus par la coalescence des chaînes de fullerènes des peapods C60 et C70 à très haute température semble indépendante de la nature des fullerènes. Le rayon moyen des nanotubes internes est estimé à 0.36 nm. Le mécanisme de formation du tube interne est discuté. Finalement la dynamique des peapods est étudiée par diffusion inélastique des neutrons. Une forte mobilité orientationnelle des fullerènes C60 est mise en évidence jusqu'à assez basses températures. Celle-ci est interprétée en considérant le caractère fortement unidimensionnel des chaînes de fullerènes.

We simulate directional solidification using a phase field model solved with an adaptive finite element method. For small surface tension anisotropy directed at 45 degree relative to the pulling direction, we have observed three types of morphology: Dendritic, seaweed, and cellular. The seaweed pattern is characterized by alternating tip splitting and the branches have no orientation preference. A crossover from the seaweed to dendritic morphology was noticed when lowering the thermal gradient, consistent with previous experimental findings. We also investigate the influence of anisotropy on the morphology. We find that the thermal gradient, pulling velocity, and anisotropy can determine the crystal morphology. We show that the morphology of crystal structures can be unambiguously characterized through the local interface velocity distribution. As the thermal gradient is lowered, large-velocity shoulders begin to appear in both transverse and growth directions, becoming progressively broader as clearly defined dendrites emerge. We derive semi-empirically an estimate for the crossover from seaweed to dendrite as a function of thermal gradient and pulling velocity, which agrees with our simulation results. The ratio of thermal length to diffusion length has a sharp "transition" at the crossover region. In the second part of the thesis, a single variable dynamic model(Model B) is proposed to study C60 ultra-thin film growth on the alkali halide substrate. A triple-well free energy is proposed to explain the coexistence of three layers. The middle well is metastable representing a single layer. We successfully recover "branched" and "compact" patterns for both deposition a
Nous simulons la solidification directionnelle en utilisant un modèle de champ de phase résolu avec la méthode d'élément fini adaptative. Pour la petite anisotropie de tension superficielle dirigée à 45 degree relativement à la direction de traction, nous avons observé trois sortes de morphologies de solidification: dendritique, algue et cellulaire. Le schéma sous forme d'algues est caractérisé par le bout alternatif se dédoublant et dont les branches n'ont aucune préférence d'orientation. Une transition du schéma d'algues vers un morphologie dendritique a été noté lorsque le gradient thermique est abaissé. Ceci est compatible avec les résultats expérimentaux précédents. Nous étudions également l'influence de l'anisotropie sur la morphologie de cristal. Nous prouvons que le gradient thermique, la vitesse de traction, et l'anisotropie peuvent déterminer la morphologie de cristal. Nous prouvons que la morphologie des structures cristallines peut être clairement caractérisée par la distribution locale de la vitesse d'interface. Pendant que le gradient thermique est abaissé, les épaules de grand-vitesse commencent à apparaître dans des directions transversales et de croissance, devenant progressivement plus large en tant que dendrites bien définies émergent. Nous dérivons semi empiriquement une approximation pour la transition du schéma d'algues vers le schéma des dendrites en fonction du gradient thermique et la vitesse de traction, ce qui est conforme à nos résultats de simulation. Le rapport de la longueur thermique à la longueur de diffusion est caractérisée par une forte "transition" dans la région de la transition. Dans la

Parmi les propriétés physico-chimiques remarquables du C60 et de ses dérivés, notons leur aptitude à jouer le rôle d’accepteur d’électron et/ou d’énergie. De ce fait, la synthèse et l’étude des propriétés électroniques de systèmes du type fullerène-donneur ont fait l’objet de nombreuses recherches. Au cours de cette thèse nous nous sommes intéressés à la préparation de nouveaux systèmes C60-donneur. Dans ce contexte, nous avons commencé par développer une méthodologie de synthèse pour la conception de briques moléculaires à base d’oligophénylènevinylène (OPV) en suivant une approche de type oligomère. Les différents systèmes conjugués ont ensuite été fonctionnalisés avec du C60 pour conduire à différents systèmes fulleropyrazolines-OPV. Pour améliorer les propriétés électroniques, de nouvelles triades C60-OPV-ferrocène ont été préparées, le ferrocène jouant le rôle de donneur d’électron supplémentaire au sein du système. Nous avons également préparé de complexes à valences mixtes à partir de ferrocène et de fullerène. Bien que différents dérivés de fullerène avec des unités ferrocènes aient déjà été décrits, aucun n’a montré les propriétés de complexes à valence mixte. Les données photophysiques ont montré la présence d’une bande d’intervalence dans un composé à valence mixte de Classe II. Il a été intéressant de constater que le couplage électronique entre les unités ferrocènes est influencé par des interactions intramoléculaires entre le C60 et le pont conjugué, et de cette façon le composé mime le comportement typique d’un transistor, mais à l’échelle moléculaire. Nous avons également préparé des bis-adduits du fullerène dans lesquels les unités ferrocènes sont remplacées par des groupements aniline en attendant que la communication électronique entre les deux sites rédox soit optimisée. Finalement, nous avons synthétisé et étudié les propriétés photophysiques d’un système combinant le C60 avec un nouveau chromophore à absorption multi-photonique
Photochemical molecular devices based on the combination of C60 with π-conjugated oligomers have generated significant research activities in the past few years. In particular, such donor-fullerene arrays have shown interesting excited state properties and have been used as photovoltaic materials in solar cells. As part of this research, we became interested in the synthesis of new covalently linked fullerene-(π-conjugated oligomer) systems with new properties. Firstly, we have attached a π-conjugated oligomer subunit to C60 through a pyrazoline ring to determine the influence of the electron donating ability of the pyrazoline ring on the photophysical properties of the hybrid compound. Secondly, more elaborated systems in which an additional donor subunit, namely ferrocene, is connected to the C60-(π-conjugated oligomer) system were also prepared and characterized. Innovative mixed-valence complexes combining two ferrocene units with the C60 sphere were prepared. Our particular interest was to prepare the first ferrocene-based mixed-valence systems bearing a fullerene unit and, to study the influence of the fullerene on the conjugated system linking the two ferrocene units, and consequently, evaluate how this can affect the electronic communication between the two ferrocenes. Interestingly, the C60 electron acceptor behaves like an applied electric field on the molecular wire and modulates its charge mobility capability, mimicking a transistor like behaviour at the molecular level. In order to improve the electronic coupling a new series of organic mixed-valence compounds bearing amines as redox centers was prepared, based on the fact that it was already demonstrated that organic mixed-valence compounds bearing amines presents electronic couplings stronger than for related inorganic mixed-valence compounds. Finally, we have prepared and studied the excited state properties of a compound assembling C60 with a multiphoton absorption chromophore

La présente thèse décrit la synthèse de briques de base de fullerènes pour la préparation de dispositifs moléculaires photoactifs combinant C60 et porphyrines. La cycloaddition alcyne-azoture catalysée au cuivre (I) a été utilisée comme outil de synthèse pour la préparation des dérivés C60 complexes.L’utilité synthétique de synthons C60 a été montrée avec la préparation d’édifices moléculaires complexes présentant des propriétés spécifiques pour diverses applications. Ainsi, un système photoactif flexible combinant C60 et porphyrine a été synthétisé. Cependant la flexibilité de l’espaceur liant les sous-unités de ce composé conduit à des variations de structurales importantes et complique ainsi l’analyse des études photophysiques.Dans ce contexte, nous nous sommes proposé dans une première partie de la présente thèse de parfaitement contrôler l’orientation et la distance des différentes sous-unités au sein de systèmes C60-donneurs. Afin de répondre à ce besoin, nous avons construit une brique de base de C60 rigide ayant un groupe azoture aromatique. Ainsi, la réaction « click » avec un phénylacétylène conjugué au groupement donneur conduit à un espaceur rigide entre les deux sous-unités.La deuxième partie de ce travail a été consacrée à la synthèse d’hexa-adduits du C60 portant différents groupements fonctionnels. Une méthode de synthèse permettant de préparer des hexa-adduits du C60 fonctionnalisés a été mise au point au laboratoire.Cette stratégie a été modifiée et des composés de C60 comportant dix fonctions azotures et une fonction alcyne protégée ont été synthétisés; dans ce cas il est possible d’introduire dans un premier temps par une réaction click dix groupes fonctionnels. Et dans un second temps; après déprotection de la fonction alcyne, une seconde réaction de click permet alors de greffer un fonctionnel différent
The present PhD thesis manuscript is focused on the use of fullerene building blocks for the preparation of photoactive molecular devices combining C60 and porphyrins. Cu(I) Catalyzed alkyne-azide cycloaddition was used as a synthetic tool for the preparation of complex C60 derivatives. Specifically, in the first part (Chapter II-B), a flexible fullerene-porphyrin triad has been developed and the photophysical studies were performed. The flexible linker between the fullerene core and the azide groups prevented any conformational control on the relative orientation and distance between the two photoactive subunits connected together. This prompted the development of an analogous building block in which the azide unit is directly connected to the bridging phenyl ring (Chapter II-C). In this way, the click reaction with porphyrin-alkyne derivatives give access to hybrid systems with a controlled relative orientation of the two moieties. This is of fundamental importance for a better understanding of the structural parameters affecting the electron and/or energy transfer kinetic in such dyads.In the second part (Chapter III), a fullerene hexaadduct scaffold is used to build up sophisticated multiporphyrin systems for various applications. The preparation of these multi-chromophoric ensembles relies on the click-click approach developed in our group

The project presented in this thesis is deal with the study of paramagnetic molecular structures for Quantum Information Processing (QIP), whose aim is the development of devices based on the principles of quantum mechanics. The aim of this work is the evaluation of the prospect of using spins in endohedral fullerenes N@C60 (made of a single nitrogen atom inside a fullerene) as basic units of quantum information (qubits). N@C60 is produced by ion implantation yielding a mixture of N@C60/C60 in a ratio of 1/10000. Extensive purification through HPLC is required to isolate the N@C60 from the empty C60. In order to purify N@C60, a collaboration was started with the group of Prof. F. Gasparrini from Università  "La Sapienza" di Roma. A new HPLC equipment known as High Performance Liquid Magneto-Chromatography (HPLMC) was developed as a result of this collaboration. The ground state of the nitrogen atom inside the cage is a quartet (S=3/2) and a paramagnetic behavior of N@C60. A very narrow EPR linewidth, due to the long electron spin relaxation times, is the distinctive feature of N@C60. The electronic spin relaxation times, tens or hundreds of microseconds at ambient temperature, are much longer than those of most paramagnetic molecules that, usually, are in the nanoseconds to few microseconds range. This remarkable property makes N@C60 particularly interesting for the realization of devices for QIP. The relaxation time for electronic spins corresponds to the coherence time. Long coherence time is a necessary condition for a quantum system to be useful as a qubit in order to execute a large number of logical operations for a given algorithm. Several papers have appeared in the literature in recent years on the relaxation properties of the electron spin in N@C60 in solution. While these solution studies have helped to understand the relaxation mechanisms of the electron spin in N@C60, solid state materials would be better suited to the realization of devices and their integration with current technologies. Deepening the understanding of relaxation mechanisms in the solid state is, therefore, crucial. In this work, the electron spin relaxation properties of a series of N@C60 derivatives (from an unpurified mixture of N@C60 and C60) were studied in order to identify the processes responsible for decoherence in the solid state and assess the suitability of N@C60 as a qubit in a solid matrix. To this aim, several molecular structures were synthesized in which N@C60 was chemically modified or included in a supramolecular architecture. Despite the many processes causing a decrease of the coherence time of N@C60 derivatives, the relaxation times measured in this work show that N@C60 is a promising building block for the realization of solid state systems that are suitable for the implementation of quantum algorithms. The derivatives presented in this work were chosen because of their suitability for the realization of ordered systems of endohedral fullerene on solid substrates such as silicon. As a consequence, a relevant part of this thesis was concerned with the study of the non-covalent immobilization of C60 on silicon surfaces with a monolayer of a calix[8]arene derivative. The long-term goal of this work is the immobilization of N@C60 onto silicon surfaces in order to develop molecular structures suitable for the manipulation of individual qubits and their interactions. I report herein the use of the non-covalent interactions between calix[8]arene receptors and fullerenes to immobilize C60 on silicon surfaces. Calix[8]arene molecules with double bond terminated alkyl chains were grafted on H-terminated Si(100) surfaces via thermal hydrosilylation of the double bonds. Pure and mixed monolayers were obtained from either pure calix[8]arene or a calix[8]arene/1-octene mixture. X-ray photoelectron spectroscopy been was used as the main tool for the monolayer characterization while atomic force microscopy was used to evaluate the supramolecular immobilization of C60. Grafting of pure calix[8]arene leads to poorly packed layers in which a small quantity of silicon oxide was found. In this system, clusters of [60]fullerene on surface were detected. By contrast, monolayers obtained from a calix[8]arene/1-octene mixture consist of densely packed layers which prevent silicon oxidation and fullerene clustering at the same time. This observation suggests that the calix[8]arene/1-octene layer was immobilized C60 on silicon surfaces through host-guestinteractions. The low quantity of N@C60 available, has prevented the EPR investigation on the paramagnetic layer made of calix[8]arene/N@C60 on silicon surfaces. Thus, in the last part of this thesis, I report on the self-assembly of a functionalized nitroxide radical onto a porous silicon surface through a hydrosilylation route. IR and XPS methods were used to confirm the composition of the nitroxide layers, whereas EPR lineshape analysis was used to extract some relevant parameters related to the layers dynamics, such as rotational diffusion tensors. Finally, a novel [70]fulleropyrrolidine functionalized with a nitroxide radical was synthesized.
Il progetto sviluppato durante il triennio di Tesi ha riguardato lo studio di strutture molecolari paramagnetiche per applicazioni nella Quantum Information Processing (QIP), un ambito di ricerca molto attivo nell'ultimo ventennio, il cui obiettivo è la realizzazione di dispositivi per l'elaborazione delle informazioni utilizzando i principi della meccanica quantistica. In particolare, questo lavoro ha avuto come obiettivo lo studio delle potenzialità dell'endofullerene d'azoto (una molecola di C60 all'interno della quale è presente un atomo di azoto) e del suo spin elettronico come unità  base per l'informazione quantistica (qubit). Normalmente, l'endofullerene d'azoto (N@C60) viene prodotto per impiantazione ionica. Questa modalità  di produzione non fornisce l'endofullerene in forma pura, ma come una miscela di N@C60/C60 non superiore a 1/10000. Per ottenere un materiale arricchito in N@C60 è necessario procedere con dispendiose procedure di purificazione via HPLC. Per mettere a punto un metodo di arricchimento più conveniente rispetto ai sistemi HPLC standard, è stata avviata una collaborazione con il gruppo del Prof. F. Gasparrini dell'Università  "La Sapienza" di Roma, finalizzata allo sviluppo di una nuova tecnica cromatografica di purificazione che utilizza un'apparecchiatura magneto-cromatografica. L'endofullerene d'azoto è una molecola paramagnetica poiché l'atomo di azoto centrale possiede lo stato elettronico fondamentale di quartetto (S=3/2). La tecnica più adatta per lo studio di questo tipo di sistema è dunque la Spettroscopia di Risonanza Elettronica (EPR). La caratteristica notevole di N@C60 è la sua larghezza di riga EPR estremamente ridotta a causa dei lunghi tempi di rilassamento di spin elettronico (alcune decine o centinaia di microsecondi a temperatura ambiente) rispetto a molecole paramagnetiche ordinarie, per le quali i tempi di rilassamento possono variare da nanosecondi a qualche microsecondo. Questa proprietà  è quella che rende N@C60 particolarmente interessante per la costruzione di dispositivi adatti alla QIP. Nel caso degli spin elettronici il tempo di rilassamento di spin corrisponde al tempo di coerenza, e tempi di coerenza sufficientemente lunghi sono una condizione necessaria perché un sistema quantistico sia utile come qubit. Questo requisito deriva dalla necessità  che il tempo di mantenimento della coerenza degli stati quantistici sia più lungo di quello richiesto per eseguire il numero di operazioni logiche che compongono un dato algoritmo. In letteratura sono apparsi negli ultimi anni alcuni studi sulle proprietà  di N@C60 in soluzione che hanno permesso di elucidare alcuni aspetti dei meccanismi di rilassamento di spin elettronico. In generale, tuttavia, è preferibile poter disporre di materiali in stato solido, sia per realizzare dispositivi in grado di effettuare calcoli quantistici, sia per facilitare un'eventuale integrazione con le tecnologie odierne. E' quindi fondamentale approfondire la conoscenza dei meccanismi di rilassamento anche allo stato solido. In questo lavoro sono state studiate le proprietà  di rilassamento di spin elettronico di una serie di derivati di N@C60 (contenuto in una miscela non purificata di N@C60/C60) al fine di identificare i principali processi che causano la decoerenza di spin allo stato solido e valutare l'idoneità  di N@C60 come possibile qubit in matrice solida. A tale scopo sono state prodotte strutture molecolari nelle quali N@C60 è soggetto a diverse modificazioni chimiche o interazioni con l'ambiente circostante. Nonostante i molteplici processi che concorrono a far diminuire il tempo di coerenza di N@C60 nei derivati, i valori dei tempi di rilassamento misurati in questo lavoro di tesi hanno dimostrato come N@C60 sia potenzialmente applicabile in sistemi allo stato solido adatti all'implementazione di algoritmi quantistici. I derivati studiati in questo lavoro sono stati scelti proprio perché offrono la possibilità di essere impiegati per realizzare sistemi ordinati di endofullerene su matrici solide, come ad esempio superfici di silicio. Una parte significativa di questo lavoro di tesi ha riguardato perciò lo studio dell'immobilizzazione del C60 su di una superficie di silicio, attraverso la formazione di complessi host-guest con un derivato del calix[8]arene preventivamente legato alla stessa superficie. L'obiettivo a lunga scadenza di tale studio è la formazione di strati di N@C60 nelle medesime condizioni messe a punto per il C60, una volta che l'endofullerene d'azoto sia disponibile in forma pura o perlomeno sotto forma di una miscela più arricchita rispetto a quella attualmente disponibile. E' stata studiata quindi la possibilità di immobilizzare un derivato del calix[8]arene recante terminazioni alcheniliche su superficie di silicio attraverso la reazione di idrosililazione termica dei doppi legami. In particolare, sono stati ottenuti dei monolayer in cui il calixarene è stato immobilizzato in forma pura oppure diluito con 1-ottene. E' stata impiegata la spettroscopia fotoelettronica a raggi X (XPS) come metodo principale per la caratterizzazione della superficie, mentre l'immobilizzazione non covalente del C60 su silicio è stata confermata attraverso l'uso della microscopia a forza atomica (AFM). La superficie di calixarene puro è risultata essere costituita da un layer non ben impaccato di molecole calixareniche e dalla presenza di una certa quantità di ossido. Questa situazione morfologica favorisce la formazione di cluster fullerenici in superficie. Dall'altro lato, il monolayer ottenuto dalla miscela calixarene/1-ottene presenta un elevato grado di impaccamento che previene sia la formazione di ossido in superficie sia la formazione di cluster fullerenici, rendendo quindi possibile la realizzazione del complesso di inclusione 60/calix[8]arene su silicio. La bassa quantità  di endofullerene nella miscela N@C60/C60 non ha permesso però la registrazione di spettri EPR con la strumentazione in nostro possesso, per cui una parte del progetto di dottorato ha riguardato lo studio EPR di un sistema modello in cui un radicale organico è stato immobilizzato su superficie di silicio, anche di tipo poroso, al fine di trovare le condizioni ottimali per registrare spettri significativi. Lo studio è stato realizzato impiegando strati di radicali nitrossilici ancorati su superfici di silicio tramite una reazione di idrosililazione termica. Attraverso l'uso di tecniche IR, XPS e di risonanza paramagnetica elettronica è stato possibile determinare il grado di ricopertura della superficie di silicio. Questo sistema allo stato solido ha permesso non solo di validare il metodo di caratterizzazione EPR per studiare superfici silicee contenenti layer di molecole paramagnetiche, ma anche di ottenere informazioni sulla dinamica dei nitrossidi legati alla superficie stessa. Durante la tesi si è inoltre conclusa una ricerca che ha riguardato la sintesi di derivati nitrossilici del fullerene C70.

In this thesis, the design and synthesis of novel C60 fullerene compounds with different functional groups is reported. Chapter 1 introduces the background of the project with a general introduction into the covalent and non-covalent types of bonding interactions, and the chemistry and reactions of C60 fullerenes. Chapter 2 focuses on co-crystallisation of pristine C60 with selected aromatic compounds. Single crystals have been obtained and characterised by X-ray diffraction. Chapter 3 is concerned with the synthesis and characterisation of novel fullerene compounds by using Prato cycloaddition reactions, such novel compounds are further characterised in the solid state by single crystal X-ray diffraction. Hirshfeld surfaces are used to investigate the non-covalent interaction of the obtained crystal structures. Chapter 4 describes the synthesis and characterisation of novel fullerene compounds by using Bingel cycloaddition reactions. Crystallisation experiments have been attempted and theoretical studies using the semi-empirical method, parameterized model number 3, have been employed to investigate the charge transfer between the ligand and the C60 molecule. The novel molecules in this work have been characterised by infrared and NMR spectroscopies, and mass spectrometry. Single crystal X-ray diffraction was used when appropriate.

Dans un premier temps, la bis- et tris-fonctionnalisation du C60 a été effectuée par une approche macrocyclique. Différents bis- et tris-adduits du C60 ont été obtenus avec de bonnes régioselectivités. Dans un deuxième temps, la tris-fonctionnalisation du C60 a été effectuée par une approche « tête directrice ». Par cette approche, un accès rapide, simple, régio- et stéréo-sélectif à des tris-adduits e,e,e approprié à la formation d’hexa-adduits d’ordre d’addition octaédrique a été obtenu. La synthèse et la séparation de tris-adduits e,e,e optiquement purs ont également été réalisées. Les dérivés polyols obtenus par déprotection des groupes silylés ouvrent de nouvelles perspectives pour la post-fonctionnalisation de multi-adduits de C60. A partir de nos méthodologies de synthèse de bis- et tris-adduits de C60, des synthons d’hexa-adduits mixtes de C60 ont été préparés. La post-fonctionnalisation de ces synthons a été effectuée par réaction de cycloaddition1,3-dipolaire de type Huisgen mais aussi par réaction d’estérification, afin d’obtenir des hexa-adduitsde C60 multifonctionnels. La méthodologie de synthèse d’hexa-adduits de C60 multifonctionnels aété mise à profit pour l’élaboration d’édifices hyperfonctionnels comportant plusieurs hexa-adduits de C60 autour d’un hexa-adduit de C60 central. La post-fonctionnalisation des synthons hexa-adduits mixtes par chimie « click » donne accès à la préparation contrôlée de nouveaux nanomatériaux globulaires multifonctionnels
In a first instance, the bis- and tris-functionalization of C60 was performed by a macrocyclic approach. Different bis- and tris-adducts of C60 were obtained with good regioselectivity. In a second instance, the tris-functionalization of C60 was performed by a “tether-directed” approach. By this approach, a fast, simple, regio- and stereoselective access to C60 e,e,e tris-adduct suitable for the formation of C60 hexa-adducts with an octahedral addition pattern was obtained. The synthesis and the separation of optically pure e,e,e tris-adducts was also realized. The polyol derivatives obtained by deprotection of the silyl groups open new perspectives for the post-functionalization of C60 multiadducts. Using our synthesis methodologies of bis- and tris-adducts of C60, mixed hexa-adducts building blocks were prepared. The post-functionalization of these building blocks was carried out by copper catalyzed azide-alkyne 1,3-dipolar cycloadditions but also by esterification reactions to obtain multifunctional C60 hexa-adducts. The methodology for the synthesis of multifunctional C60 hexa-adducts was used for the elaboration of fullerodendrimers containing several C60 hexa-adducts around a central C60 hexa-adduct. The post-functionalization of the mixed hexa-adducts building blocks by “click” chemistry gave access to the controlled preparation of new globular and multifunctional nanomaterials

A high performance vertical organic transistor based on the organic semiconductor C60 is developed in this work. The sandwich geometry of this transistor, well known from organic light-emitting diodes or organic solar cells, allows for a short transfer length of charge carriers in vertical direction. In comparison to conventional organic field-effect transistors with lateral current flow, much smaller channel lengths are reached, even if low resolution and low-cost shadow masks are used. As a result, the transistor operates at low voltages (1 V), drives current densities in the range of 10 A/cm², and enables a switching speed in the MHz range. The operation mechanism is studied in detail. It is demonstrated that the transistor can be described by a nano-porous permeable base electrode insulated by a thin native aluminum oxide film on its surface. Thus, the transistor has to be understood as two metal-oxide-semiconductor diodes, sharing a common electrode, the base. Upon applying a bias to the base, charges accumulate in front of the oxide, similar to the channel formation in a field-effect transistor. Due to the increased conductivity in this region, charges are efficiently transported toward and through the pinholes of the base electrode, realizing a high charge carrier transmission. Thus, even a low concentration of openings in the base electrode is sufficient to ensure large transmission currents. The device concept turns out to be ideal for applications where high transconductance and high operation frequency are needed, e.g. in analog amplifier circuits. The full potential of the transistor is obtained if the active area is structured by an insulating layer in order to perfectly align the three electrodes. Besides that, molecular doping near the charge injecting contact is essential to minimize the contact resistance. Due to the high power density in the vertical C60 transistor, Joule self-heating occurs, which is discussed in this work in the context of organic semiconductors. The large activation energies of the electrical conductivity observed cause the presence of S-shaped current-voltage characteristics and result in thermal switching as well as negative differential resistances, as demonstrated for several two-terminal devices. A detailed understanding of these processes is important to determine restrictions and proceed with further optimizations
In dieser Arbeit wird ein vertikaler organischer Transistor mit hoher Leistungsfähigkeit vorgestellt, der auf dem organischen Halbleiter C60 basiert. Die von organischen Leuchtdioden und organischen Solarzellen bekannte \'Sandwich’-Geometrie wird verwendet, so dass es möglich ist, für die vertikale Stromrichtung kurze Transferlängen der Ladungsträger zu erreichen. Im Vergleich zum konventionellen organischen Feldeffekttransistor mit lateralem Stromfluss werden dadurch viel kleinere Kanallängen erreicht, selbst wenn preisgünstige Schattenmasken mit geringer Auflösung für die thermische Verdampfung im Vakuum genutzt werden. Daher kann der Transistor bei einer Betriebsspannung von 1 V Stromdichten im Bereich von 10 A/cm² und Schaltgeschwindigkeiten im MHz-Bereich erreichen. Obwohl diese Technologie vielversprechend ist, fehlt bislang ein umfassendes Verständnis des Funktionsmechanismus. Hier wird gezeigt, dass der Transistor eine nanoporöse Basiselektrode hat, die durch ein natives Oxid auf ihrer Oberfläche elektrisch isoliert ist. Daher kann das Bauelement als zwei Metall-Oxid-Halbleiter-Dioden verstanden werden, die sich eine gemeinsame Elektrode, die Basis, teilen. Unter Spannung akkumulieren Ladungsträger vor dem Oxid, ähnlich zur Ausbildung eines Ladungsträgerkanals im Feldeffekttransistor. Aufgrund der erhöhten Leitfähigkeit in dieser Region werden Ladungsträger effizient zu und durch die Öffnungen der Basis transportiert, was zu hohen Ladungsträgertransmissionen führt. Selbst bei einer geringen Konzentration von Löchern in der Basiselektrode werden so hohe Transmissionsströme erzielt. Das Bauelementkonzept ist ideal für Anwendungen, in denen eine hohe Transkonduktanz und eine hohe Schaltgeschwindigkeit erreicht werden soll, z.B. in analogen Schaltkreisen, die kleine Signale verarbeiten. Das volle Potential des Transistors offenbart sich jedoch, wenn die aktive Fläche durch eine Isolatorschicht strukturiert wird, um den Überlapp der drei Elektroden zu optimieren, so dass Leckströme minimiert werden. Daneben ist die Dotierung der Molekülschichten am Emitter essentiell, um Kontaktwiderstände zu vermeiden. Aufgrund der hohen Leistungsdichten in den vertikalen C60-Transistoren kommt es zur Selbsterwärmung, die in dieser Arbeit im Kontext organischen Halbleiter diskutiert wird. Die große Aktivierungsenergie der Leitfähigkeit führt zu S-förmigen Strom-Spannungs-Kennlinien und hat thermisches Umschalten sowie negative differentielle Widerstände zur Folge, was für verschiedene Bauelemente demonstriert wird. Ein detailliertes Verständnis dieser Prozesse ist wichtig, um Beschränkungen für Anwendungen zu erkennen und um entsprechende Verbesserungen einzuführen

The donor-acceptor couple CuPc/C60 has been the subject of recent studies in organic solar cells due to its combined abilities in light absorption (CuPc) and charge transport (C60). By better understanding the electronic and geometric nature of the system it is possible to shed light on how the molecules act under different conditions. In this study the geometric properties for three different configurations have been studied by means of Density Functional Theory (DFT). By comparing the molecular structure of pristine CuPc with the structure of CuPc in the presence of C60, a slight elongation of the bonds is observed when the fullerene is present. This is especially true for the Cu-N bonds. By further including van der Waals interactions, no change in bond lengths is observed. This, in turn, suggests that, most likely, the interaction between the two molecules is relatively weak and the C60 will not have a major influence on the electronic structure of CuPc. The N1s X-ray Photoelectron Spectroscopy (XPS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) calculations confirm these conclusions, as only very small changes in peak positions are observed when comparing pristine CuPc with CuPc/C60.
Tack vare sina egenskaper inom absorption och laddningsöverföring har CuPc och fullerenen C60 varit föremål för omfattande studier bland forskare inom organiska solceller. Genom att få större förståelse för den geometriska såväl som den elektroniska konfigurationen inom och mellan paret kan man förutse hur dessa kommer att bete sig i olika sammansättningar. I denna studie har de geometriska förutsättningarna studerats där olika konfigurationer beräknats genom täthetsfunktionalteori (DFT). Genom att mäta bindningslängderna mellan koppar, kol och de olika typer av kväve i CuPc i de olika systemen, kan det inses att bindningarna förlängs då C60 läggs till. Då van der Waals-interaktioner inkluderades observerades ingen större förändring i bindingslängderna i jämförelse med fallet utan van der Waals-interaktioner. Detta tyder på att växelverkan mellan de två molekylerna är relativt svag och att C60-fullerenen ej har någon större påverkan på elektronkonfigurationen i CuPc. Beräkningarna av N1s X-ray Photoelectron Spectroscopy (XPS) och Near Edge X-ray Absorption Fine Structure (NEXAFS) stödjer denna slutsats då endast små skiftningar i topparna observerades vid jämförelse mellan rent CuPc och CuPc/C60.

The magnetic properties of spin doped fullerenes are investigated in hybrid organic/inorganic structures with the aim of establishing the extent to which magnetic states can be induced and controlled in these materials. Volume magnetometry is used to measure a reduction of net magnetization and an increase in coercivity in cobalt which can be understood in terms of a transfer of majority spin electrons from the transition metal d-band into spin polarized hybrid interface states. This is supported by PNR and XAS studies of Co/C60 which reveal AF coupling between Co metal films and a hybrid interfacial region where magnetic ground states are induced in fullerenes through charge transfer. Investigations of hybridization between C60 and the RE-TM alloy CoGd show that the compensation temperature of the ferrimagnet is altered by the presence of C60. PNR measurements of CoGd/C60 MLs reveal interfacial coupling which creates an AF region 1.5 $\pm$ 0.1 nm thick. Magnetometry of Gd/C60 bilayers indicates that hybridization between the metal conduction bands and the C60 LUMO modifies magnetic ordering in Gd. This is supported by the observation of novel features in the temperature dependence of magnetization and resistivity in the composite. XAS of Gd/C60 bilayers shows a large peak in the carbon K-edge at 282 eV which is attributed to interfacial hybridization. It is shown that PL quenching in C60 is greater over Co than Au which is attributed to the greater electron transfer between Co and C60. PL quenching is proposed as an effective way to measure magnetic coupling and electron transfer in interfaces. Raman spectra are recorded in C60 junctions during spin polarised transport. The Ag(2) peak splitting is shown to depend on the polarisation of injected current acting as an effective probe of triplet formation in C60. Finally, XAS at the carbon K-edge is recorded during spin transport. A suppression of the LUMO to zero and increase in the intensity of the 282 eV peak occurs after removal of external bias and is shown to be reversible and repeatable under cycles of grounding and charge injection. A proposed mechanism involving the redistribution of charge following the removal of bias which causes electrons to become trapped in interfacial states is suggested.

碩士
淡江大學
化學學系
85
The electrochemical behavior of C60 and C70 films on glassy carbon electrode with tetraalkylammonium salts(NR4+; R=CH3, C2H5, C3H7, C4H9) in acetonitrile solution was investigated by cyclic voltammetiy(CV). The cyclic voltammogram of such films showing an unusual hystersis suggested that large structural changes occur on reduction. We described the first well-resolved cyclic voltammogram of C60 and C70 films with small size cations (NR4+;R=CH3, C2H5, C3H7) by using an ultramicro-electrochemical cell technique. These results, accompanied by electrochemical quartz crystal microbalance(EQCM) method, led the doping process of NR4+ and dissolution process of fUlleride being able to be characterized in detail to understand the structures as well as phases of doped films. Different phase of doped C60 and C70 films, such C60n-(NR4+)m and C70n-(NR4+)m (n=1,2;m=0,1,2), were proposed to investigate the four reduction peaks of fullerene from neutral to -2 charge. A comparative of the system will be discussed.

碩士
逢甲大學
電機工程學系
87
The study of the thesis is aimed at the dielectric properties of C60、C70. Besides, observe the discontinuous phase-transform at T = 260 K of C60, moreover, find that the conductivity of C60 satisfied the theory of hopping. On the other hand, according to experiment finding that C60 has dipole phenomenon when T > 200 K. Further, when f = 1 MHz, C60 dielectric is 10 at T = 150 K and 16 at T = 300 K. That is to say, thermally-activated process effect can affect the dielectric of C60. We also investigate relaxation-time、Cole-Cole plote. When Gd2CuO4 discover ME effect. The system of R2CuO4 compound cause to search fashion. But, the dopping Sr ion in Gd2CuO4 has no person to investigate up to now. So, deepen interesting that we research the material. I use solid-state method to process materials. By experiment we can know that the structure are not center symmetry, smaller grain size, more kind elements (the same structure), more defect all can cause to larger dielectric constant and conductivity. Keyword：C60、Gd2CuO4、Dielectric Constant

A study of the recently discovered molecular allotrope of carbon, C60 (buckminsterfullerene) is presented. The preparation of this potentially useful new material is described, along with its characterisation by X-ray powder diffraction, scanning electron microscopy, mass spectrometry, infrared spectroscopy and ultraviolet/visible/near-infrared spectroscopy. To a lesser extent, its congener C70 is also described. The newly discovered spectra of the C601-, C602-, C603-, and C604- anions of C60 are characterised and used in a novel preparation of the superconducting Rb3C60 salt in liquid ammonia. This method is the first to allow determination of the oxidation state of C60 during synthesis, and also provided the first near-infrared spectroscopic observation of the C605- anion. The nature of the synthesis is such as to allow stoichiometric synthesis of other alkali metal compounds also. The products of the liquid ammonia synthesis were analysed by X-ray diffraction and microwave susceptibility (to determine superconductivity temperatures).

碩士
國立清華大學
化學學系
83
In recent years,so many papers reported a photoinduced polymerization of C60 films and hypothesized that it results from the formation of a (2+2) cycloaddition when C60 is generated to C120. Now we want to investigate a new mechanism in solution phase whether C60 precede self-disproportionation and recombination to form C60 polymers or not. By theoretical and experimental evidence, that is more favorable than cycloaddition The harvesting of light energy by plants and its conversion to chemically useful forms are utmost importance to mankind. The artificially mimicking photosynthesis involving electron transfer is not very efficient to store light energy. Here we provide direct evidence about C60 for storage of light energy. The photoinduced product can exist a lot of months without back electron transfer. Our experiments contain three parts, including part I: "the self-disproportionation of triplet C60", part II: "the tabilizatin of C60 radical cation & C60 radical anion by organicalt", and part III: "the continued reactin of C60 radical C60 radical anion".

博士
國立清華大學
化學系
87
I. The fluorescene emission of pyrene was quenched by C60 in various hydrocation solvent, such toluene isodurene etc. The Stern-Volmer plot shows that the fluorescene intensity ratio Io/I is upward , and is non linearly proportional to the fullerene concentration. Electronic absorption measurmes show that pyrene and C60 do not form static complex under the current experimental condition. At a given C60 concentration , increased either solvent polarity or temperature affords diminishment in the ratio . The fluorscene quenching behavior by C70 shows a similar pattern . The data strongly suggest that even at concentration far below saturation , Stern-Volmer fullerene forns aggregates in Organic solvent. II. a stable , broad ESR signal of C60-. anion radical was generated by irradiation of a C60-toluene solution in the presence of organic salt, [(Ph)3P]2N+(Ph)4B-, and 14.3 % methanol. Upon exposure to molecular oxygen , the broad band gradually diminishes and a narrow band of g = 2.0008 and Hpp = 3.32 G grow , which further transforms to another narrow band of g = 2.0026 and Hpp = 1.67 G .The transforation rate found to be negnetive temperature dependent , the higk temperatures and the slower the transfomation .

碩士
國立嘉義大學
光電暨固態電子研究所
98
In this thesis, using synchrotron-radiation photoemission spectroscopy, we have studied the interfacial properties of the rubrene/C60 and C60/rubrene heterojunctions. The valence-band and C 1s core-level spectra have showed that there were charges transfer from the rubrene to the C60 at both heterointerfaces, resulting in significant interfacial dipole potential. In the C60/rubrene, upon C60 deposition, the highest occupied molecular orbital of rubrene was split and a gap state of C60 appeared. However, the results did not reveal in the rubrene/C60 case, indicating that its interaction was weaker than that of the C60/rubrene interface. Important interface parameters and hole-injection barriers were obtained. It has showed that the sequence of deposition could influence the electronic properties of the interfaces.

碩士
淡江大學
化學學系
82
The electrochemical behaviors of C60 films , which are prepared on electrode by casting method , during redox processes in acetontrile were examined by means of cyclic voltammetry ( CV ) and electrochemical quartz crystal microbalance ( EQCM ) technique in various condition. The tetraethylammonium perchlorate was used supporting electrolyte. In the CV behavior , there are four reductive waves at R1 = -1.17V R2 = -1.25V R3 = -1.40V R4 = -1.55V (vs. Fc/Fc+ ) corresponding to C60(TEA+)/ C60-1(TEA+), C60/C60-1, C60-(TEA+)/C60-2(TEA+) , and C60-/ C60-2, respectively. There are four oxidative waves at O4 = -1.29V O3 = -1.06V O2 = -0.76V O1 = -0.55V (vs. Fc/Fc+) corresponding to C60-2 deposition, C60-1/C60 C60-2(TEA+)2/C60-1( TEA+)2, C60-1(TEA+)/C60(TEA+), respectively The dissolution/ deposition of C60-n(n=1,2) and doping/dedoping of TEA+ on C60 films at diffrernt potential are investigated and approved by EQCM and dual working electrode CV studied.

碩士
國立臺中教育大學
科學教育與應用學系碩士班
104
The equilibrium structures, harmonic vibrational frequencies, ionization energies, and electron affinities of the fullerene dimer (C60)2C2 and its derivative (C60)2C2H2, including their cations and anions, were computed by the density functional theory (B3LYP) associated with the 3-21G and 6-31G(d) basis sets. The photoelectron spectra of ionizing the neutral molecule to form the cation and detaching an electron from the anion to form the neutral molecule were simulated by computing Franck-Condon factors with the approach developed by our group. The primary findings of this study are as follows. In (C60)2C2, two C60 units can either end-bonded or side-bonded to the C=C moiety. There are two isomers (cis- or trans-) of (C60)2C2H2. The trans-(C60)2C2H2 belongs to the C2h point group, whereas the other molecules studied belong to the C2v point group. The point group of each molecule is the same as their cation and anion. We have predicted the adiabatic ionization energies and adiabatic electron affinities of these molecules. Importantly, each molecule has a distinct pattern in its photoelectron spectrum, which serves as a reference for future experimental identification of the species.

Le fullerène C60, une molécule sphérique, et le C70, un analogue ellisoïde, sont des composés aromatiques convexes constitués exclusivement d'atomes de carbone. La nature aromatique de la surface de ces cages de carbone rend possible leur association à l'état solide avec d'autres molécules aromatiques de topologie complémentaire. En particulier, l'association des fullerènes avec des composés présentant des motifs concaves aromatiques, via une association de type concave-convexe, est favorable. En effet, les interactions π•••π de type concave-convexe sont amplifiées grâce à la complémentarité topologique des partenaires impliqués. Le centrohexaindane est un hydrocarbure non planaire rigide qui a été synthétisé pour la première fois en 1988 par Kuck et collaborateurs. Cette molécule possède quatre surfaces aromatiques concaves orientées dans une géométrie tétraédrique qui sont susceptibles d'interagir favorablement avec les fullerènes. Nous avons ainsi avec succès cocristallisé le centrohexaindane avec les fullerènes C60 et C70. Puis, nous avons étudié les assemblages à l'état solide entre le centrohexaindane et les fullerènes par l'analyse des structures résolues via diffraction des rayons X. Les surfaces concaves aromatiques du centrohexaindane se sont révélées être propices à une association avec les fullerènes C60 et C70 via des interactions π•••π de type concave-convexe, tel que prévu. En outre, nous avons découvert que les liaisons C-H situées à la périphérie du centrohexaindane prennent part à une multitude de contacts C-H•••π avec les molécules de fullerène. Les échantillons de cocristaux composés de centrohexaindane et de fullerène ont aussi été caractérisés par diffraction de poudre des rayons X et par analyse thermogravimétrique dans le but d'en évaluer l'homogénéité.
Spherical fullerene C60 and C70, its ellipsoidal analogue, are convex aromatic compounds consisting exclusively of carbon atoms. The aromatic nature of the surface of these carbon cages enables their solid-state association with aromatic molecules that have complementary shapes. In particular, the association of fullerenes with compounds that have concave aromatic units, by a concave-convex type of association, is favored. Indeed, concave-convex π•••π interactions are enhanced because of the topological complementarity of the partners. Centrohexaindane is a rigid nonplanar hydrocardon that was first synthesized in 1988 by Kuck and coworkers. It contains four concave aromatic surfaces, oriented in a tetrahedral geometry, that are likely to interact favorably with fullerenes. To study this phenomenon, we successfully cocrystallized centrohexaindane with fullerenes C60 and C70. We then resolved the structure of the resulting solid-state assemblies by X-ray diffraction. The concave aromatic surfaces of centrohexaindane proved to be conducive for an association with fullerenes involving concave-convex π•••π interactions, as expected. In addition, we found that C-H bonds located at the periphery of centrohexaindane participate in a variety of C-H•••π contacts with the fullerene partners. Samples of cocrystals containing centrohexaindane and fullerene were also characterized using powder X-ray diffraction and thermogravimetric analysis in order to assess their homogeneity.

Since the discovery of the buckyball in 1985, researchers have imagined its potential in fields ranging from materials science to medicinal chemistry. The unique size, shape and hydrophobicity of C 60 fullerene endow it with the ability to interact with biological superstructures such as enzymes and membranes making it attractive as a potential pharmacophore. In this regard, we have developed a new, simple route to water soluble fullerene amino acids, both alkyl and aryl, through the dipolar addition of azido starting materials. The synthesis of our phenylalanine derivative, including the chromatographic purification, requires only one day for its completion. We have subsequently used our C 60 phenylalanine derivative in the synthesis of a series of C 60 peptides for the purposes of enzyme inhibition, specifically human immunodeficiency virus Type 1 protease, a critical viral enzyme responsible for the maturation of the virus and a popular target of medicinal chemists. We have demonstrated the ability of our C 60 amino acids and peptides to inhibit HIV-1 PR in a cell-free fluorescence based assay at low nanomolar concentrations. Graphite, or specifically graphene, has recently come to the forefront of nanomaterials research due to it similar scale, properties, and reaction pathways as other more costly carbon nanostructures such as carbon nanotubes. We have demonstrated the high yield functionalization of graphitic starting materials through the thermal decomposition of azido amino acids to their corresponding nitrene. The result is an inexpensive, highly functionalized, carbon based scaffold.