Les phosphines alkyl primaires ont la réputation d’être des composés très sensibles à l’air, parfois même pyrophoriques. Pour cette raison, leur application en tant que ligands est assez restreinte. L'introduction de substituants encombrants qui peuvent stabiliser les phosphines primaires est une méthode pour diminuer leur sensibilité à l'oxygène. Les hydrocarbures ayant une structure cage, comme les diamantoïdes, peuvent donc être des substituants idéaux pour stabiliser les phosphines primaires. Le travail décrit dans cette thèse porte sur la synthèse et les applications de phosphines primaires diamantoïdes. Premièrement, leur utilisation en tant que blocs de construction pour l’élaboration des matériaux organo-hybrides via des dépôts en phase vapeur sera illustrée. D'autre part, leur utilisation en tant que ligands dans des réactions d'arylation de N-hétérocycles (typiquement l’indole) catalysées par des métaux sera présentée.Une avancée importante dans la chimie des diamantoïdes est représentée par leur découverte et leur isolement en grande quantités à partir de sources naturelles telle que le pétrole. La fonctionnalisation des diamantoïdes composés d'un plus grand nombre de cages que l'adamantane a été explorée pour la première fois au milieu des années 60. Diverses fonctions chimiques ont été introduites sur le squelette type cage de ces hydrocarbures, résultant en de nouveaux dérivés aux propriétés exceptionnelles. Afin d'explorer pleinement le potentiel de ces molécules, la dissymétrisation des cages a été étudiée en tant que moyen d'obtention des blocs structurels bien définis avec deux fonctionnalités différentes. Auparavant, l’obtention de deux fonctions chimiques différentes sur le squelette de ces hydrocarbures a été rendue possible par des séquences de protection / déprotection.Notre premier objectif était de développer une nouvelle approche synthétique gouvernée par la réaction contrôlée de manière cinétique dans des milieux acides forts donnant accès direct à des diamantoïdes difonctionnalisés. Cette stratégie a été développée avec succès pour les diamantoïdes phosphorylés qui, après réduction, ont donné une nouvelle classe de phosphines alkyle primaires qui se sont révélées relativement stables à l'air. La post-fonctionnalisation de ces phosphines a également été réalisée et sera discutée dans la section des résultats non-publiés.Des progrès révolutionnaires ont été accomplis au cours de la dernière décennie dans le domaine des nanomatériaux à base de carbone sp2, tels que les fullerènes, les nanotubes de carbone et les graphènes. En comparaison, les matériaux basés sur du carbone sp3, tels que ceux incorporant des diamantoïdes, composés qui combinent à la fois quelques caractéristiques uniques du diamant et des nanostructures de carbone, restent mal connus à ce jour. Dans ce chapitre, la synthèse d'un nouveau matériau organohybride ayant une structure constituée d’un coeur organique (diamantoïde) et d’une surface métallique (typiquement, palladium ou platine) sera discutée.L'indole est un hétérocycle azoté largement intégré en chimie médicinale comme sous-unité structurale de médicaments pour le traitement du diabète de type 2, du cancer et du VIH. Ce motif est également présent dans une variété de produits naturels, constituant ainsi une cible en synthèse organique. Trois stratégies de synthèse sont possibles pour obtenir des indoles fonctionnalisés et seront décrites dans la section d'introduction.Dans ce chapitre, l'activation C–H en position C2 du (N–H) indole sera décrite. Cette réaction a été conduite en milieux aqueux, sous air, et à l’aide des phosphines primaires diamantoïdes décrites dans le Chapitre 1 utilisées ici comme ligands du palladium en milieu biphasique. Les iodures d'aryle ont été testés en tant que partenaires de couplage, et la réaction s’est révélée sélective pour la position C2 avec des très bons rendements. / Widespread application of primary alkyl phosphines is limited due to their high sensitivity towards oxidation, often resulting in pyrophoricity. Introduction of bulky substituents that can kinetically stabilize primary phosphines is one method for decreasing their oxygen sensitivity. Bulky cage hydrocarbons like diamondoids, which are naturally occurring molecules, can therefore be ideal substituents for stabilizing primary phosphines. The work described herein deals with the synthesis and applications of primary diamondoid phosphines. Firstly, they are used as building blocks for the construction of organo-hybrid materials by mild vapor deposition, and secondly, as ligands in metal catalyzed arylation reactions of N-heterocycles.An important advance in the chemistry of diamondoids was made possible after their discovery and isolation in large quantities from natural sources like petroleum. Functionalization of diamondoids composed of higher number of cages than adamantane was first explored in the mid-1960s. Various functionalities have been introduced onto diamondoids resulting in new derivatives with outstanding properties. In order to fully explore the potential of these molecules, desymmetrization of the cages was investigated as a means for obtaining well-defined structural building blocks with two different functionalities suitable for thin film growth. This process had been achieved previously only by protection/deprotection sequences.Our first aim was to develop a new synthetic approach governed by the kinetically controlled reaction in strong acidic media, which enables direct access to unequally functionalized diamondoids. This type of reaction was successful for phosphorylated diamondoids which upon reduction gave diamondoid primary phosphines, a new class of pure alkyl primary phosphines that were found to be relatively air stable. Further post-functionalization of these molecules was also achieved and will be discussed in the unpublished results section.Revolutionary progress was made during the last decade in the area of novel carbon nanomaterials, such as sp2-C based fullerenes, nanotubes, and graphenes. In comparison, sp3-C materials based on a diamondoid scaffold that combines the unique features of both diamond and carbon nanostructures are unknown to date.Unlike metal nanocomposites based on sp2-carbon skeletons, which benefit from a rich surface chemistry due to many functional groups, metal/sp3-carbon based nanostructures are much less developed and many challenging functionalization issues remain. In this chapter, the synthesis of novel organohybrid material with core-shell like structure will be discussed. The core of the hybrid is made of organic molecules, namely diamondoids, and the shell is made of a thin transition metal layer, such as palladium or platinum.Indole is a nitrogen-containing heterocycle widely used in medicinal chemistry as a structural subunit of drug candidates for the treatment of type 2 diabetes, cancer and HIV. This scaffold is also present in a variety of natural products, therefore constituting a target in organic synthetic chemistry. Three synthetic strategies are possible to obtain functionalized indoles and will be described in the introduction.In this chapter, the C–H activation of unprotected indole moiety in position 2 of the heterocycle will be described. The reaction was done in aqueous media under aerobic conditions and diamondoid primary phosphines were used as ligands in this biphasic synthesis. Aryl iodides were tested as coupling partners and the reaction was selective for the C2 position affording excellent yields of the desired arylated indoles. With aryl bromides, a loss in selectivity was observed; yet the reaction proceeded with a surprising P/Pd ratio of 0.5/1.

Orientador: Douglas Soares Galvão / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-10T00:38:23Z (GMT). No. of bitstreams: 1 Troche_KarlaSouza_D.pdf: 4475542 bytes, checksum: 174644e87f1d2a1a584c4b840a379b95 (MD5) Previous issue date: 2007 / Resumo: Este trabalho apresenta o estudo teórico de nano-estruturas de carbono de interesse em nanociência. Ele envolve o estudo estrutural, eletrônico e mecânico de estruturas híbridas que são o resultado do encapsulamento de moléculas de carbono (em nosso caso: fulerenos e diamondóides) inseridas em nanotubos de carbono. Utilizando métodos clássicos de Dinâmica Molecular fizemos um estudo do ordenamento molecular dos fulerenos de simetria esférica como o C 60, fulerenos assimétricos C 70 e C78 e diamondóides. Para observar à dependência da ordenação molecular na simetria cilíndrica com o tamanho do nanotubo de carbono e simetria molecular da molécula inserida. Com simulações de dinâmica molecular investigamos as mudanças das propriedades mecânicas de nanotubos de carbono quando são preenchidos com moléculas de C60 e diamondoides. Previmos as mudanças no material e características promissoras das estruturas híbridas. Aplicamos o método Tight-binding baseado na teoria do funcional da densidade para determinar as propriedades eletrônicas dos novos híbridos Fulerenos@nanotubo de carbono. Previmos mudanças nas propriedades e potenciais aplicações em nanotecnologia / Abstract: This work presents a theoretical study of carbon nanostructures with great interest in nanoscience world. It is about the structural, electronic and mechanical study of hybrid structures that result from encapsulation of carbon molecules (fullerenes and diamondoids) introduced inside carbon nanotubes. Using classical methods of molecular dynamics we performed a study of molecular ordering of fullerenes with spherical geometry, C60, asymmetric fullerenes C70 and C78 and diamondoids. We observed dependence of the molecular ordering on cylindrical geometry with the carbon nanotube size and the geometry of the inserted molecule. Through molecular dynamics simulations, we investigated the change on mechanical properties of carbon nanotubes when filled with C60 molecules and diamondoids. We also predict changes on the material and promising characteristics of hybrid structures. We applied the Tight-binding method based on the theory of density functional to determine the electronic properties of the new hybrid fullerenes@carbon nanotube. We predict interesting properties and powerful applications on nanotechnology / Doutorado / Física da Matéria Condensada / Doutor em Ciências

A number of MIR sensing platforms and methods were developed in this research work demonstrating potential applicability of MIR spectroscopy for studying hydrocarbon systems in extreme environments. First of all, the quantitative determination of the diamondoid compound adamantane in organic media utilizing IR-ATR spectroscopy at waveguide surfaces was established. The developed analytical strategy further enabled the successful detection of adamantane in real world crude oil samples. These reported efforts provide a promising outlook for detection and monitoring of diamondoid constituents in naturally occurring crudes and petroleum samples. IR-ATR spectroscopy was further utilized for evaluating and characterizing distribution, variations, and origin of carbonate minerals within sediment formations surrounding a hydrocarbon seep site - MC 118 in the Gulf of Mexico. An analytical model for direct detection of 13C-depleted authigenic carbonates associated with cold seep ecosystems was constructed. Potential applicability of IR-ATR spectroscopy as direct on-ship - and in future in situ - analytical tool for characterizing hydrocarbon seep sites was demonstrated. MIR evanescent field absorption spectroscopy was also utilized to expand the understanding on the role of surfactants during gas hydrate formation at surfaces. This experimental method allowed detailed spectroscopic observations of detergent-related surface processes during SDS mediated gas hydrate formation. The obtained IR data enabled proposing a mechanism by which SDS decreases the induction time for hydrate nucleation, and promotes hydrate formation. Potential of MIR fiberoptic evanescent field spectroscopy for studying surface effects during gas hydrate nucleation and growth was demonstrated. Next, quantifying trace amounts of water content in hexane using MIR evanescent field absorption spectroscopy is presented. The improvement in sensitivity and of limit of detection was obtained by coating an optical fiber with layer of a hydrophilic polymer. The application of the polymer layer has enabled the on-line MIR detection of water in hexane at low ppm levels. These results indicate that the MIR evanescent filed spectroscopy method shows potential for in-situ detection and monitoring of water in industrial oils and petroleum products. Finally, quantification of trace amounts of oil content in water using MIR evanescent field absorption spectroscopy is reported. Unmodified and modified with grafted hydrophobic polymer layer silver halide optical fibers were employed for the measurements. The surface modification of the fiber has enabled the on-line MIR analysis of crude oil in water at the low ppb level. Potential application of MIR fiber-optic evanescent field spectroscopy using polymer modified waveguides toward in-situ low level detection of crude oil in open waters was demonstrated.