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Funcionalização covalente e não covalente de nanotubos de carbono / Covalent functionalization and noncovalent carbon nanotubesFeitosa, Johnny Peter Macedo January 2009 (has links)
FEITOSA, J. P. M. Funcionalização covalente e não covalente de nanotubos de carbono. 2009. 72 f. Dissertação (Mestrado em Química) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2009. / Submitted by Daniel Eduardo Alencar da Silva (dealencar.silva@gmail.com) on 2014-11-17T18:09:47Z
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Previous issue date: 2009 / The work developed in this thesis consists in the study of the process of non covalent functionalization of carbon nanotubes with triblock and diblock copolymers and covalent functionalization of carbon nanotubes with stearic acid. The non covalent functionalization of carbon nanotubes were realized using triblock copolymer [triblock E69S15E69, E69S7E69 (E= ethylene oxide, S = styrene oxide), E65G7E65 (E = ethylene oxide, G = phenyl glycidyl ether), the diblock copolymer E20CL10 (E = ethylene oxide, CL = Ɛ-caprolactone)] e SDS (sodium dodecyl sulfate). The individualization of carbon nanotubes with copolymer and SDS, were performed by stirring, sonication and centrifugation. The resulting samples were characterized using the Raman resonant spectroscopy study, exciting in wavelength of 532 nm (2.33 eV). The photoluminescence studies, in the copolymers and SDS solution, were realized using a detector InGaAs for detecting light in the intermission of 800 – 1700 nm, and a lamp of Xe, exciting in spectral intermission of 500 – 850 nm. The characterizations were used to identify the type of semiconductors carbon nanotubes, by photoluminescence, as well as the other identified by resonant Raman spectroscopy and the aspects that showing the individualization of carbon nanotubes using copolymers matrix. The covalent functionalization of carbon nanotubes were realized using stearic acid. The functionalization was performed in three steps, carboxylation of carbon nanotubes, usingfor this the mixture H2SO4:HNO3, functionalization of carbon nanotubes with COCl groups and functionalization of carbon nanotubes with stearic acid. The characterization of the obtained sample was realized using the Raman resonant spectroscopy study, exciting with laser at wavelength of 514,5 nm (2,41 eV), FTIR, DSC, in N2 atmosphere and heating rate of 10ºC/min in the intermission of 25 – 400 ºC, and TGA, in N2 atmosphere and heating rate of 10 ºC/min with intermission 25 – 900 ºC. These characterizations were realized in order to confirm the covalent functionalization of the carbon nanotubes with stearic acid, obtaining shift in the crystalline structure of the carbon nanotubes, showed by the Raman resonant spectroscopy study and corresponding -OOC-O-COO- anhydride bond also showed in the FTIR spectroscopy, as well as change in the thermal behavior of the carbon nanotubes functionalized in comparison with pure carbon nanotubes. / O trabalho desenvolvido nesta dissertação consiste no estudo do processo de funcionalização não covalente de nanotubos de carbono com copolímeros tribloco e dibloco e a funcionalização covalente de nanotubos de carbono com ácido esteárico. A funcionalização não covalente dos nanotubos de carbono foi realizada utilizando copolímeros tribloco e dibloco [tribloco E69S15E69, E69S7E69 (E = óxido de etileno, S = óxido de estireno), E65G7E65(E = óxido de etileno, G = óxido de fenilglicidil), o copolímero dibloco E20CL10 (E = óxido de etileno, CL = Ɛ-caprolactona)]. A individualização dos nanotubos de carbono com os copolímeros (em solução) foi realizada usando a técnica de agitação, sonicação e centrifugação. As amostras obtidas foram caracterizadas por espectroscopia Raman ressonante excitando com laser de comprimento de onda de 532 nm (2,33 eV), e por fotoluminescência no intervalo de 800 – 1700 nm. As caracterizações foram realizadas de forma a identificar os tipos de nanotubos semicondutores, por fotoluminescência, assim como também os demais por espectroscopia Raman. As características espectrais comprovam a individualização dos nanotubos de carbono utilizando os copolímeros como meio dispersivo. A funcionalização covalente dos nanotubos de carbono foi realizada empregando ácido esteárico, e desenvolvida em 3 etapas: i) carboxilação dos nanotubos de carbono utilizando a mistura H2SO4:HNO3; ii) funcionalização dos nanotubos com grupos COCl e iii) funcionalização dos nanotubos de carbono com ácido esteárico. A caracterização da amostra obtida foi realizada usando espectroscopia Raman ressonante, com excitação no comprimento de onda de 514,5 nm (2,41 eV), FTIR, DSC em atmosfera de N2 e taxa de aquecimento de 10 ºC/min no intervalo de 25 a 400 ºC, e TGA em atmosfera de N2 e taxa de aquecimento de 10ºC/min no intervalo de 25 a 900 ºC. Estas caracterizações foram realizadas de modo a obter elementos que indiquem a funcionalização covalente dos nanotubos de carbono com o ácido esteárico. Essa funcionalização reflete mudançaas na estrutura cristalina dos nanotubos de carbono, observada na espectroscopia Raman ressonante e bandas correspondentes a ligações -OOC-O-COO- típica de anidrido nos espectros de FTIR, assim como mudanças no comportamento térmico dos nanotubos funcionalizados em relação aos nanotubos de carbono puro.
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Funcionalização de nanocelulose de celulose bacteriana com colágeno hidrolisado / Functionalization with collagen hydrolyzate of nanacelulose bacterialGina Alejandra Gil Giraldo 12 September 2016 (has links)
A nanocelulose vêm se destacando devido a suas propriedades físico-químicas únicas, elevada pureza, alto índice de cristalinidade, biodegradabilidade e benefícios ambientais causados pelo seu uso, hoje é profundamente estudada com intuito de desvendar suas potencialidades. Processos como funcionalização de superficies utilizando polimeros têm despertado grande atenção, devido a sua vasta gama de aplicações tecnológicas, além disso, sua versatilidade pode ser muito incrementada pela otimização de suas propriedades através deste processo. Diante disso, a nanocelulose foi produzida e funcionalizada com colágeno hidrolisado (NCW-Co) a partir de celulose bacteriana. Para obtenção de fibras de celulose em nanoescala, o método utilizado foi hidrolise com ácido sulfúrico (H2SO4), já que as regiões amorfas das fibras celulósicas são solúveis em ácidos, enquanto que as regiões cristalinas não. A nanoclulose produzida (NCW) passou por reações de succiniliação (NCW-sc), seguida de funcionalização (NCW-co). A través da técnica de FT-IR foi possivel evidenciar a funcionalização da nanocelulose. Outras técnicas também foram utilizadas para caracterização como microscopia óptica de luz polarizada (MOLP), microscopia de força atómica (MFA) e análise termogravimétria (ATG/DTG). Foi escolhida outra técnica, a microbalança de cristal de quartzo (QCM), na identificação da funcionalização, com esta técnica é possível relacionar a variação de frequência na oscilação no cristal de quartzo e a variação de massa na superfície do mesmo, permitindo acompanhar continuamente a quantidade de massa depositada sobre o cristal de quartzo. Quando estabelecidos os parâmetros de padronização da técnica, foi possivel comprovar a funcionalização em tempo real. O QCM é, provavelmente, a técnica mais utilizada na avaliação in-situ do processo de construção de filmes. As alterações realizadas na estrutura da nanocelulose no processo de funcionlização, proporcionando novas e melhores caracteristicas a serem aplicadas pela industria. / The nanocelulose have stood out due to their unique physicochemical properties, high purity, high degree of crystallinity, biodegradability and environmental benefits arising from its use today is deeply studied in order to unlock its potential. Processes such as functionalization of surfaces using polymers have attracted great attention, due to its wide range of possible technological applications, in addition, its versatility can be much enhanced by optimization its properties through this process. Therefore, the nanocelulose was produced and functionalized with collagen hydrolyzate (NCW-Co) from bacterial cellulose. To obtain cellulose fibers at the nanoscale, the method used was hydrolysis with sulfuric acid (H2SO4) as amorphous regions of the cellulose fibers are soluble in acid, while the crystalline regions does not. The produced nanocelulose (NCW) passed by reactions succinylation (NCW-sc), followed by functionalization (NCW-co). Through FT-IR technique it was possible to demonstrate the functionalization of nanocelulose. Other techniques were also used to characterize as Polarized Light Microscopy Optics (PLMO), Atomic Force Microscopy (AFM) and thermogravimetry (TGA / DTG). It was chosen another technique, quartz crystal microbalance (QCM), for the identification of functionalization, with this technique it is possible to relate the frequency change in oscillation of the quartz crystal and the mass variation on the surface of it, allowing continuously monitor the amount mass deposited on the quartz crystal. When established the technical standardization of parameters, it was possible to prove the functionalization in real time. The QCM is probably the most used technique in-situ evaluation film-building process. Changes made in nanocelulose structure in functionalization process optimize their properties by providing new and better features to be applied by the industry.
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Funcionalização de grafite em condições de Friedel-Crafts / Graphite Functionalization in Friedel-Crafts conditions.David Tatsuo Atique Sawazaki 30 September 2013 (has links)
Neste trabalho foi realizada a funcionalização de grafite sem prévio tratamento em condições de Fridel-Crafts. Considerando que a grafite não possui hidrogênio em sua estrutura, não se observa uma reação de substituição eletrofílica. Por outro lado, o trabalho mostra o papel da umidade presente no grafite na reação de funcionalização. Dessa forma, foi proposto um mecanismo para a reação com a participação da água adsorvida na grafite estabilizando o carbocátion formado. O grafite funcionalizado obtido na reação foi utilizado como material eletródico. Para a reação de funcionalização, quatro moléculas foram utilizadas: ácido ferrocenomonocarboxílico, cloreto de 4-nitrobenzoíla, cloreto de 3,5-dinitrobenzoíla e ácido 3,4-dinitrobenzóico. Para o estudo das condições ótimas da reação, utilizou-se diferentes potências de radiação no reator de micro-ondas, sendo que a extensão da funcionalização mostrou-se sensível à variação deste parâmetro. Para a caracterização dos materiais, utilizou-se voltametria cíclica e análise térmica (TG e DTA). Resultados de infravermelho e Ramam são apresentados no Apêndice A. Os resultados eletroquímicos mostraram que os materiais funcionalizados em maiores potências apresentaram maior corrente Faradaica, mas ao mesmo tempo, o material obtido foi mais resistivo. A diferença de potencial relacionada ao processo redox do ferroceno aumentou conforme a extensão da funcionalização, uma vez que um sobrepotencial é necessário devido ao fluxo iônico (para a manutenção da eletroneutralidade) relativo ao número de espécies envolvidas. Os resultados eletroquímicos também indicaram que a funcionalização do grafite com os nitro compostos foi baixa. A análise térmica evidenciou que a reação de funcionalização do grafite com o ferroceno resultou em materiais com 15% a 20% (m/m) de material ligado ao grafite. Os materiais funcionalizados a maiores potências apresentaram maior massa ligada ao grafite. A funcionalização com os nitro compostos resultou em materiais com menos de 3% (m/m) de composto ligado ao grafite. Os resultados das duas técnicas mostraram coerência na análise da extensão da funcionalização. O material funcionalizado com o ácido ferrocenomonocarboxilico foi o que apresentou os melhores resultados e propõe-se uma explicação para tal baseado no mecanismo de reação sugerido. Com o objetivo de melhor elucidar o mecanismo da reação, foram realizadas algumas reações na ausência de alguns reagentes. Por exemplo, quando tenta-se funcionalizar o material sem a presença de cloreto de alumínio ou sem a umidade natural do grafite, a reação não ocorre. / In this work natural graphite functionalization in Fridel-Crafts conditions is performed using a one-step microwave assisted reaction. Since there is no hydrogen in graphite structure, it is not possible to observe electrophilic substitution. On the other hand this work shows the role of the moisture present on graphite in the functionalization reaction under this condition. Therefore, a reaction mechanism with the participation of the water naturally adsorbed on graphite stabilizing the formed carbocation has been suggested. After the reaction, the functionalized graphite was used as electrode material. Four molecules were used to functionalize graphite: Ferrocene monocarboxylic acid, 4-nitrobenzoyl chloride, 3,5-dinitrobenzoyl chloride and 3,4-dinitrobenzoic acid. To study the optimal conditions of the reaction, the microwave radiation power was varied and the extent of the functionalization on graphite was sensitive to this parameter. Two techniques were used to characterize the materials, cyclic voltammetry and thermal analysis (TG and DTA). IR and Raman data are shown in appendix A. Electrochemical results have shown that the materials functionalized at higher microwave radiation power have higher Faradaic current, but are more resistive. The potential difference between the peaks of the redox process of ferrocene increased with the extent of functionalization. This occurs because an overpotencial is needed to compensate the ionic flux (in order to maintain the electroneutrality) related to the number of species involved. The electrochemical results also indicated that the extent of functionalization of graphite with the nitro compounds was low. The thermal analysis have shown that the functionalization of graphite with ferrocene lead to values between 15% to 20% (m/m) of compound in the material. The materials functionalized at higher microwave radiation power presented higher relative mass in the material. The reaction with the nitro compounds lead to less than 3% (m/m) of compound in the final material. The results of both techniques were coherent about the extent of functionalization. The material functionalized with ferrocene monocarboxylic acid showed the best results, and an explanation for that based on the reaction mechanism is suggested. In order to elucidate the reaction mechanism, some experiments were realized in absent of some reagents. When the reaction were carried out without aluminum chloride or with dried graphite, the reaction has not occurred.
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Funcionalização de tecidos têxteis com nanopartículas para proteção UV / Functionalization of textile fabrics with nanoparticles for UV protectionLuz Esmeralda Roman Mendoza 06 June 2018 (has links)
Nos últimos anos no Brasil, instituições como o Instituto Nacional de Câncer José Alencar Gomes da Silva e o Ministério da Saúde, reportaram o aumento de casos de câncer de pele. O câncer de pele é uma das doenças mais comuns a nível mundial e pode estar relacionado à exposição à radiação ultravioleta (UV). O objetivo do presente trabalho foi realizar a funcionalização de tecidos sarja 100% algodão com nanopartículas (NPs) de óxido de zinco (ZnO), as quais possuem propriedades para aplicação como protetor solar, melhorando desta forma as características de proteção à radiação UV do algodão. As NPs de ZnO foram sintetizadas pelo processo de precipitação, empregando nitrato de zinco hexahidratado (Zn(NO3)2.6H2O) e hidróxido de sódio (NaOH). A síntese in situ das NPs de ZnO sobre os tecidos foi realizada por meio do processo de esgotamento, usando o equipamento de tingimento têxtil HT (High Temperature). Para este processo foram utilizadas diferentes concentrações de Zn(NO3)2.6H2O (2, 5, 8 e 10% sobre a massa do tecido) e NaOH (0,7; 1,6; 2,5 e 3,0 g/L), respectivamente. A avaliação do fator de proteção UV (FPU) e os testes de resistência à lavagem dos tecidos foram realizados segundo normas as AATCC 183:2004 e AATCC 61:1996, respectivamente. Foram promovidas também aplicações de resinas têxteis comerciais sobre os tecidos funcionalizados e determinação das propriedades físicas. Além disso, foram realizadas caracterizações de vibração molecular, estruturais e morfológicas das NPs de ZnO e para os tecidos funcionalizados foram efetuadas caracterizações estruturais, morfológicas e térmicas. Os resultados mostraram que tanto as NPs de ZnO como as sintetizadas in situ sobre os tecidos apresentaram estrutura cristalina hexagonal wurtzite. As NPs de ZnO mostraram uma morfologia de estrela com pontas muito protuberantes enquanto que as NPs sintetizadas no tecido apresentaram morfologia similar, mas com pontas pequenas. Para todas as concentrações de nitrato de zinco estudadas, antes e após as 20 lavagens, o FPU dos tecidos funcionalizados com NPs de ZnO tiveram categoria de proteção UV entre boa e excelente / In Brazil, institutions such as the José Alencar Gomes da Silva National Cancer Institute (INCA) and the Brazilian Ministry of Health reported increase and appearance of new types of cancer in recent years. Skin cancer is the most common type of disease worldwide and generally might be related to the exposure of the skin to ultraviolet (UV) radiation generated by the sun. The objective of this work was to perform the functionalization of 100% cotton woven fabrics with zinc oxide (ZnO) nanoparticles (NPs), which has interesting properties for applications as solar protector, thus improving the protection characteristics of cotton against UV radiation. ZnO NPs were synthesized by the precipitation process using zinc nitrate hexahydrate (Zn(NO3)2.6H2O) and sodium hydroxide (NaOH). In situ synthesis of ZnO NPs onto the fabric was carried out via exhaust dyeing method, using the textile High Temperature (HT) dyeing machine. For this process, different concentrations of Zn(NO3)2.6H2O (2, 5, 8 and 10% on the weight of fabric) and NaOH (0.7, 1.6, 2.5 and 3.0 g/L) were used. The evaluation of UV protection factor (UPF) and wash durability tests were performed according to AATCC 183:2004 and AATCC 61:1996 standards, respectively. Commercial textile resins applications onto functionalized fabrics and determination of physical properties were also performed. In addition, molecular, structural and morphological characterizations of ZnO NPs were carried out and structural, morphological and thermal analyzes were performed for functionalized fabric. The results showed that both ZnO NPs and those in situ synthesized onto the fabric, exhibited wurtzite hexagonal crystalline structure. The ZnO NPs displayed a star-like morphology with very pronounce tips, while the NPs onto the fabric had a similar morphology but with small tips. For all concentrations of zinc nitrate studied, before and after 20 cycles washing, the UPF of cotton fabrics functionalized with ZnO NPs had an UV-protection category between good to excellent
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Direct functionalization of heterocyclic and non-heterocyclic arenesMousseau, James J. 11 1900 (has links)
L’application des métaux de transition à la fonctionnalisation directe a ouvert la voie à une nouvelle classe de réactions pour la formation de liens carbone-carbone. De par l'omniprésence des liaisons C–H, l’introduction de nouvelles fonctionnalités chimiques par voie directe et pré-activation minimale s’impose comme une stratégie de synthèse très attrayante. Ainsi, il est envisageable de préparer de manière rapide et efficace des supports complexes menant à des molécules complexes, qui pourraient être utiles dans divers domaines de la chimie.
L'objectif principal de la présente thèse vise la fonctionnalisation directe des arènes hétérocycliques et non hétérocycliques et, plus précisément, les techniques d’arylation. Dans un premier temps, nous allons aborder le thème de l’arylation directe tout en mettant l’accent sur les pyridines (Chapitre 1). Ces molécules sont à la base d'une multitude de composés biologiquement actifs et jouent un rôle important dans le domaine des sciences des matériaux, de l’agrochimie et de la synthèse des produits naturels. Dans un deuxième temps, nous discuterons de nos travaux sur l’arylation directe catalysé par un complex de palladium sur des ylures de N-iminopyridinium en soulignant la dérivatisation du sel de pyridinium après une phénylation sp2 (Chapitre 2). L’étude de ce procédé nous a permis de mettre en lumière plusieurs découvertes importantes, que nous expliquerons en détails une à une : l’arylation benzylique directe lorsque des ylures N-iminopyridinium substituées avec un groupement alkyl à la position 2 sont utilisés comme partenaires dans la réaction; les allylations Tsuji-Trost catalysée par un complex de palladium; et l’alkylation directe et sans métal via une catalyse par transfert de phase.
Plusieurs défis restent à relever pour le développement de procédés directs utilisant des métaux de transition peu coûteux, d’autant plus que la synthèse par transformation directe des pyridines 2-alcényles, lesquelles sont pertinentes sur le plan pharmacologique, n’a pas encore été rapportée à ce jour. Avec cette problématique en tête, nous avons réussi à mettre au point une alcénylation directe catalysé par un complex de cuivre sur des ylures de N-iminopyridinium. Nous discuterons également d’une nouvelle méthode pour la préparation des iodures de vinyle utilisés dans les couplages. Ces réactions sont non seulement remarquablement chimiosélectives, mais sont aussi applicables à plusieurs substrats (Chapitre 3). En optimisant ce procédé direct, nous avons découvert une façon unique de synthétiser les pyrazolo[1,5-a]pyridines 2-substituées (Chapitre 4). Le mécanisme global met en jeu une séquence tandem de fonctionnalisation-cyclisation directe et un procédé direct en cascade, qui n’avais jamais été rapporté. Cela simplifie ansi la synthèse autrement compliquée de ces substrats en y apportant une solution à un problème de longue date.
Dans les deux derniers chapitres, nous examinerons en détail les techniques d’arylation directe qui n'impliquent pas les partenaires de couplage hétérocycliques. Entre autres, au Chapitre 5, nous soulignerons notre découverte d’un umpolung dirigé et catalysé par un complexe de palladium du benzène et de quelques autres dérivés arènes. Il s’agit là du premier cas de fonctionnalisation directe dans laquelle le groupe directeur se trouve sur le partenaire halogène et il s’ajoute à la courte liste d’exemples connus dans la littérature rapportant une arylation directe du benzène. Finalement, au Chapitre 6, nous passerons en revue une nouvelle arylation directe catalysée au fer, qui se veut un procédé peu coûteux, durable et présentant une économie d’atomes. Nous discutons des substrats possibles ainsi des études mécanistiques réalisés. / The application of transition metals towards direct functionalization processes has exposed an opportunistic new class of carbon-carbon bond forming reactions. Given the undeniable ubiquity of C–H bonds, the possibility of introducing functionality through direct means with minimal preactivation is an irresistible strategy in synthesis. As such one can envision rapidly and efficiently building up complex scaffolds towards complex molecules of interest in a plethora of chemical fields.
The focus of this thesis is on the direct functionalization of heterocyclic and non-heterocyclic arenes, focusing on arylation technologies. First, the topic of direct arylation will be introduced, with special emphasis being on pyridines (Chapter 1). These molecules comprise the backbone of a myriad of biologically active compounds, and are also relevant in material sciences, agrochemicals, and natural products synthesis. This will be followed by a discussion of work on the palladium-catalyzed direct arylation of N-iminopyridinium ylides with accent on the derivatization of the pyridinium following the sp2 phenylation (Chapter 2). The exploration of this process led to the discovery of direct benzylic arylation when 2-alkyl N¬-iminopyridinium ylides are employed as reacting partners, in addition to palladium-catalyzed Tsuji-Trost allylations, and metal-free direct alkylation via phase transfer catalysis. All of these findings will be discussed in detail.
There remains a significant challenge in developing direct processes utilizing inexpensive transition metals. Furthermore, the synthesis of pharmacologically relevant 2-alkenyl pyridines through direct transformations had not yet been reported. We focused on these challenges and developed a copper-catalyzed direct alkenylation of N-iminopyridinium ylides. A novel method to prepare the vinyl iodide coupling partners will also be discussed. The scopes of these reactions are quite large and remarkably chemoselective (Chapter 3). Through the optimization of this direct process we uncovered an unique means of synthesizing 2-substituted pyrazolo[1,5-a]pyridines (Chapter 4). The global process involved a tandem direct functionalization/cyclization sequence, and may be the first account of a direct process used in a cascade. This work also solves an important problem, as the synthesis of these substrates through alternate means is not straightforward.
The last two chapters will detail direct arylation technologies that do not involve heterocyclic coupling partners. Chapter 5 will highlight our uncovering of a palladium-catalyzed, directed, umpolung arylation of benzene and other arene derivatives. This was the first account of a direct functionalization whereby the directing group is situated on the pseudo electrophile. Also, it adds to the few examples of direct benzene arylation exisiting in the literature. Finally, a discussion of an atom economical, inexpensive, sustainable iron-catalyzed direct arylation process will be presented with special emphasis on substrate scope and mechanistic investigations (Chapter 6).
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Intramolecular Direct Functionalization of Cyclopropanes via Silver-Mediated, Palladium CatalysisLadd, Carolyn L. 08 1900 (has links)
Au cours de la dernière décennie, le domaine de la fonctionnalisation directe des liens C–H a connu un intérêt croissant, en raison de la demande de processus chimiques moins dispendieux, plus efficaces et plus écologiques. . Les cyclopropanes représentent un motif structural souvent retrouvé dans des agents biologiquement actifs importants et dans des intermédiaires de synthèse permettant l'accès à des architectures complexes. Malgré leur valeur intrinsèque, la fonctionnalisation directe des cyclopropanes n’a pas été largement explorée. Ce mémoire traitera de deux méthodologies liées, mais tout aussi différentes, impliquant la fonctionnalisation directe des liens C–H cyclopropaniques impliquant des réactions intramoléculaires catalysées par un complex de palladium et assistées par l’argent. Le premier chapitre présentera d’abord un bref survol de la littérature sur les fondements de la fonctionnalisation directe ainsi que les contributions majeures réalisées dans ce domaine. L’accent sera notamment mis sur la fonctionnalisation des centres sp3 et sera souligné par des exemples pertinents. Les découvertes clés concernant le mécanisme et les cycles catalytiques de ces processus seront discutées.
Le second chapitre décrira comment les 2-bromoanilides peuvent être utilisés pour accéder à des motifs particuliers de type spiro 3,3’ oxindoles cyclopropyliques. L'optimisation et l’étendue de la réaction seront abordés, suivis par des études mécanistiques réfutant l’hypothèse de la formation d’un intermédiaire palladium-énolate. Ces études mécanistiques comprennent une étude cinétique de l'effet isotopique ainsi que des études sur épimérisation; celles-ci ont confirmé que la réaction se produit par arylation directe.
Sur la base des résultats obtenus dans le deuxième chapitre, nous aborderons ensuite la fonctionnalisation directe des benzamides cyclopropyliques lesquels, après une ouverture de cycle, donneront de nouveaux produits benzo [c] azépine-1-ones (chapitre trois). Après avoir présenté une brève optimisation et l’étendue de la réaction, nous discuterons des études mécanistiques impliquées à déduire l'ordre des événements dans le cycle catalytique et à déterminer le rôle des réactifs. Celles-ci permetteront de conclure que la fonctionnalisation de l’unité cyclopropyle se produit avant l’ouverture de cycle et que l'acétate est responsable de la déprotonation-métalation concertée.
Le dernier chapitre (chapitre quatre) traitera en rétrospective de ce qui a été appris à partir de deux méthodologies divergentes et connexes et de comment ces résultats peuvent être exploités pour explorer d’autres types de fonctionnalisations directes sur des cyclopropanes. / Over the last decade, the field of direct C–H functionalization has expanded as a consequence of the demand for cheaper, more efficient and greener chemical processes. Cyclopropanes represent a privileged moiety possessing numerous functions including the use as important biologically active agents and as useful synthetic intermediates towards accessing complex architectures. Despite their inherent value, cyclopropanes have not been widely explored as targets for direct C¬–H functionalization processes.
This thesis will discuss two related but equally different methodologies involving the direct C–H functionalization of cyclopropanes via intramolecular palladium-catalyzed, silver-mediated reactions. Chapter One will provide a brief glimpse into the foundations of direct functionalization and the contribution of these original findings towards key themes and concepts currently utilized in this field. Challenges and strategies associated with the direct functionalization of sp3 centers will be highlighted with pertinent examples. Recent contributions from the literature towards directly functionalizing cyclopropanes will also be addressed. Key investigations regarding the mechanism and catalytic cycles for these processes will also be discussed.
Chapter Two will describe how 2-bromoanilides can be used to access valuable spiro 3,3’-cyclopropyl oxindoles. The optimization and scope for this project will be discussed, followed by mechanistic studies to disprove the formation of a putative palladium-enolate. These mechanistic studies include a kinetic isotope effect and epimerization experiments, both of which confirmed that the reaction proceeds via a direct arylation manifold.
Based on the findings from Chapter Two, the direct functionalization of cyclopropyl benzamides will be presented, whereby subsequent ring-opening gives rise to novel benzo[c]azepin-1-ones (Chapter Three). After presenting a brief optimization and scope, mechanistic studies will be presented to support the proposed catalytic cycle. Isomerization studies will also be discussed for both benzazepinone products. This section will conclude that cyclopropyl C–H functionalization occurs prior to ring-opening and that acetate is responsible for mediating the concerted-metallation deprotonation event.
The final chapter (Chapter Four) will conclude with insights into what has been learned from both divergent, yet related methodologies and how these findings can be exploited to further explore other direct functionalizations targeting cyclopropanes.
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Fonctionnalisation de polymères et applications en cosmétique / Polymers functionalization and applications in cosmeticsDelattre, Émilie 29 October 2013 (has links)
L’alcool polyvinylique a été fonctionnalisé avec des aldéhydes et des acides boroniques dans le but d’obtenir des polymères pouvant apporter de la brillance tout en étant solubles dans les formulations de rouges à lèvres ou de vernis à ongles. De bons taux de fonctionnalisation ont été obtenus permettant d’avoir une bibliothèque de poly(vinyl acétals) et de poly(vinyl esters boroniques) d’une cinquantaine de polymères. Une multi-fonctionnalisation du PVA a été effectuée pour obtenir des polymères alliant ces deux propriétés. Cinq poly(vinyl acétals) ont ainsi permis d’apporter une forte brillance à des rouges à lèvres. La E-poly-L-lysine a également été fonctionnalisée avec diverses cétones afin d’obtenir de nouvelles poly-4-imidazolidinones. Ces polymères sont prometteurs pour des applications dans des produits cosmétiques tels que des soins. Ils ont également été utilisés en catalyse organique asymétrique. / Poly(vinyl alcohol) has been functionalized with aldehydes and boronic acids to obtain polymers with high shining and being soluble in cosmetic formulations as lipsticks or nail polishes. Good grafting rates have been obtained permitting to have a library of about fifty poly(vinyl acetals) and poly(vinyl boronic esters). Multi-functionalization has been developped to obtain polymers having these both properties. Five polymers gave strong shining to lipsticks. E-poly-L-lysine was also functionalized with several ketones to obtain new poly-4-imidazolidinones. These polymers are promising for cosmetic applications as skincare products. They were also used for organocatalysis.
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Fonctionnalisations catalytiques de la lignine Kraft / Catalytic functionalizations of kraft ligninDumont, Clément 31 October 2018 (has links)
Les bioraffineries lignocellulosiques sont en plein essor car elles offrent des alternatives innovantes et économiquement viables aux produits issus des industries pétrolières. La lignine, un des trois constituants majoritaires de la structure cellulaire végétale, pose des problématiques de valorisation en raison de sa structure complexe et diversifiée. Ce biopolymère, constitué de polyphénols, représente pourtant la plus grande ressource naturelle et renouvelable de molécules aromatiques. De nombreuses recherches visent à fonctionnaliser cette lignine pour en améliorer ses propriétés. La très grande majorité des modifications de la lignine présente l’inconvénient de générer des sels et sous-produits en quantités stœchiométriques. Des méthodes de fonctionnalisation plus propres sont donc recherchées. Ce manuscrit de thèse présente de nouvelles méthodes de greffage catalytiques s’appuyant sur l’utilisation de butadiène, monoxyde de carbone et alcool allylique comme réactifs d’alkylation/acylation propres. Ces fonctionnalisations influent significativement sur les propriétés physico-chimiques de la lignine. De plus l’insertion d’insaturations au sein de la lignine ouvre de nouvelles voies de fonctionnalisation et de réticulation pour la synthèse de nouveaux matériaux biosourcés. / Lignocellulosic biorefineries are rapidely developing as they offer alternatives to petroleum industries’s products. Lignin, one of the three main constituent of plant cell, is hardly valorized due to its complex and diversified structure. This biopolymer, made of polyphenols, is the largest natural and renewable resource of aromatic molecules. Many researches aim at functionalizing lignin in order to improve its properties. Most of lignin modifications have the disadvantage of generating salts and by-products in stoichiometric amounts. Cleaner functionalization methods are consequently needed. This thesis manuscript presents new catalytic grafting methods based on the use of butadiene, carbon monoxide and allylic alcohol as clean, efficient and economic alkylation/acylation reagents. These functionalizations have a significant impact on the physicochemical properties of lignin. In addition, the presence of new unsaturations in the material opens the way to further functionalization and crosslinking pathways.
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Direct functionalization of heterocyclic and non-heterocyclic arenesMousseau, James J. 11 1900 (has links)
L’application des métaux de transition à la fonctionnalisation directe a ouvert la voie à une nouvelle classe de réactions pour la formation de liens carbone-carbone. De par l'omniprésence des liaisons C–H, l’introduction de nouvelles fonctionnalités chimiques par voie directe et pré-activation minimale s’impose comme une stratégie de synthèse très attrayante. Ainsi, il est envisageable de préparer de manière rapide et efficace des supports complexes menant à des molécules complexes, qui pourraient être utiles dans divers domaines de la chimie.
L'objectif principal de la présente thèse vise la fonctionnalisation directe des arènes hétérocycliques et non hétérocycliques et, plus précisément, les techniques d’arylation. Dans un premier temps, nous allons aborder le thème de l’arylation directe tout en mettant l’accent sur les pyridines (Chapitre 1). Ces molécules sont à la base d'une multitude de composés biologiquement actifs et jouent un rôle important dans le domaine des sciences des matériaux, de l’agrochimie et de la synthèse des produits naturels. Dans un deuxième temps, nous discuterons de nos travaux sur l’arylation directe catalysé par un complex de palladium sur des ylures de N-iminopyridinium en soulignant la dérivatisation du sel de pyridinium après une phénylation sp2 (Chapitre 2). L’étude de ce procédé nous a permis de mettre en lumière plusieurs découvertes importantes, que nous expliquerons en détails une à une : l’arylation benzylique directe lorsque des ylures N-iminopyridinium substituées avec un groupement alkyl à la position 2 sont utilisés comme partenaires dans la réaction; les allylations Tsuji-Trost catalysée par un complex de palladium; et l’alkylation directe et sans métal via une catalyse par transfert de phase.
Plusieurs défis restent à relever pour le développement de procédés directs utilisant des métaux de transition peu coûteux, d’autant plus que la synthèse par transformation directe des pyridines 2-alcényles, lesquelles sont pertinentes sur le plan pharmacologique, n’a pas encore été rapportée à ce jour. Avec cette problématique en tête, nous avons réussi à mettre au point une alcénylation directe catalysé par un complex de cuivre sur des ylures de N-iminopyridinium. Nous discuterons également d’une nouvelle méthode pour la préparation des iodures de vinyle utilisés dans les couplages. Ces réactions sont non seulement remarquablement chimiosélectives, mais sont aussi applicables à plusieurs substrats (Chapitre 3). En optimisant ce procédé direct, nous avons découvert une façon unique de synthétiser les pyrazolo[1,5-a]pyridines 2-substituées (Chapitre 4). Le mécanisme global met en jeu une séquence tandem de fonctionnalisation-cyclisation directe et un procédé direct en cascade, qui n’avais jamais été rapporté. Cela simplifie ansi la synthèse autrement compliquée de ces substrats en y apportant une solution à un problème de longue date.
Dans les deux derniers chapitres, nous examinerons en détail les techniques d’arylation directe qui n'impliquent pas les partenaires de couplage hétérocycliques. Entre autres, au Chapitre 5, nous soulignerons notre découverte d’un umpolung dirigé et catalysé par un complexe de palladium du benzène et de quelques autres dérivés arènes. Il s’agit là du premier cas de fonctionnalisation directe dans laquelle le groupe directeur se trouve sur le partenaire halogène et il s’ajoute à la courte liste d’exemples connus dans la littérature rapportant une arylation directe du benzène. Finalement, au Chapitre 6, nous passerons en revue une nouvelle arylation directe catalysée au fer, qui se veut un procédé peu coûteux, durable et présentant une économie d’atomes. Nous discutons des substrats possibles ainsi des études mécanistiques réalisés. / The application of transition metals towards direct functionalization processes has exposed an opportunistic new class of carbon-carbon bond forming reactions. Given the undeniable ubiquity of C–H bonds, the possibility of introducing functionality through direct means with minimal preactivation is an irresistible strategy in synthesis. As such one can envision rapidly and efficiently building up complex scaffolds towards complex molecules of interest in a plethora of chemical fields.
The focus of this thesis is on the direct functionalization of heterocyclic and non-heterocyclic arenes, focusing on arylation technologies. First, the topic of direct arylation will be introduced, with special emphasis being on pyridines (Chapter 1). These molecules comprise the backbone of a myriad of biologically active compounds, and are also relevant in material sciences, agrochemicals, and natural products synthesis. This will be followed by a discussion of work on the palladium-catalyzed direct arylation of N-iminopyridinium ylides with accent on the derivatization of the pyridinium following the sp2 phenylation (Chapter 2). The exploration of this process led to the discovery of direct benzylic arylation when 2-alkyl N¬-iminopyridinium ylides are employed as reacting partners, in addition to palladium-catalyzed Tsuji-Trost allylations, and metal-free direct alkylation via phase transfer catalysis. All of these findings will be discussed in detail.
There remains a significant challenge in developing direct processes utilizing inexpensive transition metals. Furthermore, the synthesis of pharmacologically relevant 2-alkenyl pyridines through direct transformations had not yet been reported. We focused on these challenges and developed a copper-catalyzed direct alkenylation of N-iminopyridinium ylides. A novel method to prepare the vinyl iodide coupling partners will also be discussed. The scopes of these reactions are quite large and remarkably chemoselective (Chapter 3). Through the optimization of this direct process we uncovered an unique means of synthesizing 2-substituted pyrazolo[1,5-a]pyridines (Chapter 4). The global process involved a tandem direct functionalization/cyclization sequence, and may be the first account of a direct process used in a cascade. This work also solves an important problem, as the synthesis of these substrates through alternate means is not straightforward.
The last two chapters will detail direct arylation technologies that do not involve heterocyclic coupling partners. Chapter 5 will highlight our uncovering of a palladium-catalyzed, directed, umpolung arylation of benzene and other arene derivatives. This was the first account of a direct functionalization whereby the directing group is situated on the pseudo electrophile. Also, it adds to the few examples of direct benzene arylation exisiting in the literature. Finally, a discussion of an atom economical, inexpensive, sustainable iron-catalyzed direct arylation process will be presented with special emphasis on substrate scope and mechanistic investigations (Chapter 6).
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Intramolecular Direct Functionalization of Cyclopropanes via Silver-Mediated, Palladium CatalysisLadd, Carolyn L. 08 1900 (has links)
Au cours de la dernière décennie, le domaine de la fonctionnalisation directe des liens C–H a connu un intérêt croissant, en raison de la demande de processus chimiques moins dispendieux, plus efficaces et plus écologiques. . Les cyclopropanes représentent un motif structural souvent retrouvé dans des agents biologiquement actifs importants et dans des intermédiaires de synthèse permettant l'accès à des architectures complexes. Malgré leur valeur intrinsèque, la fonctionnalisation directe des cyclopropanes n’a pas été largement explorée. Ce mémoire traitera de deux méthodologies liées, mais tout aussi différentes, impliquant la fonctionnalisation directe des liens C–H cyclopropaniques impliquant des réactions intramoléculaires catalysées par un complex de palladium et assistées par l’argent. Le premier chapitre présentera d’abord un bref survol de la littérature sur les fondements de la fonctionnalisation directe ainsi que les contributions majeures réalisées dans ce domaine. L’accent sera notamment mis sur la fonctionnalisation des centres sp3 et sera souligné par des exemples pertinents. Les découvertes clés concernant le mécanisme et les cycles catalytiques de ces processus seront discutées.
Le second chapitre décrira comment les 2-bromoanilides peuvent être utilisés pour accéder à des motifs particuliers de type spiro 3,3’ oxindoles cyclopropyliques. L'optimisation et l’étendue de la réaction seront abordés, suivis par des études mécanistiques réfutant l’hypothèse de la formation d’un intermédiaire palladium-énolate. Ces études mécanistiques comprennent une étude cinétique de l'effet isotopique ainsi que des études sur épimérisation; celles-ci ont confirmé que la réaction se produit par arylation directe.
Sur la base des résultats obtenus dans le deuxième chapitre, nous aborderons ensuite la fonctionnalisation directe des benzamides cyclopropyliques lesquels, après une ouverture de cycle, donneront de nouveaux produits benzo [c] azépine-1-ones (chapitre trois). Après avoir présenté une brève optimisation et l’étendue de la réaction, nous discuterons des études mécanistiques impliquées à déduire l'ordre des événements dans le cycle catalytique et à déterminer le rôle des réactifs. Celles-ci permetteront de conclure que la fonctionnalisation de l’unité cyclopropyle se produit avant l’ouverture de cycle et que l'acétate est responsable de la déprotonation-métalation concertée.
Le dernier chapitre (chapitre quatre) traitera en rétrospective de ce qui a été appris à partir de deux méthodologies divergentes et connexes et de comment ces résultats peuvent être exploités pour explorer d’autres types de fonctionnalisations directes sur des cyclopropanes. / Over the last decade, the field of direct C–H functionalization has expanded as a consequence of the demand for cheaper, more efficient and greener chemical processes. Cyclopropanes represent a privileged moiety possessing numerous functions including the use as important biologically active agents and as useful synthetic intermediates towards accessing complex architectures. Despite their inherent value, cyclopropanes have not been widely explored as targets for direct C¬–H functionalization processes.
This thesis will discuss two related but equally different methodologies involving the direct C–H functionalization of cyclopropanes via intramolecular palladium-catalyzed, silver-mediated reactions. Chapter One will provide a brief glimpse into the foundations of direct functionalization and the contribution of these original findings towards key themes and concepts currently utilized in this field. Challenges and strategies associated with the direct functionalization of sp3 centers will be highlighted with pertinent examples. Recent contributions from the literature towards directly functionalizing cyclopropanes will also be addressed. Key investigations regarding the mechanism and catalytic cycles for these processes will also be discussed.
Chapter Two will describe how 2-bromoanilides can be used to access valuable spiro 3,3’-cyclopropyl oxindoles. The optimization and scope for this project will be discussed, followed by mechanistic studies to disprove the formation of a putative palladium-enolate. These mechanistic studies include a kinetic isotope effect and epimerization experiments, both of which confirmed that the reaction proceeds via a direct arylation manifold.
Based on the findings from Chapter Two, the direct functionalization of cyclopropyl benzamides will be presented, whereby subsequent ring-opening gives rise to novel benzo[c]azepin-1-ones (Chapter Three). After presenting a brief optimization and scope, mechanistic studies will be presented to support the proposed catalytic cycle. Isomerization studies will also be discussed for both benzazepinone products. This section will conclude that cyclopropyl C–H functionalization occurs prior to ring-opening and that acetate is responsible for mediating the concerted-metallation deprotonation event.
The final chapter (Chapter Four) will conclude with insights into what has been learned from both divergent, yet related methodologies and how these findings can be exploited to further explore other direct functionalizations targeting cyclopropanes.
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