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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Réduction de pyridines pour la synthèse de Building-Blocks chiraux : peptidomimétiques de type imidazolique : synthèse et application à la synthèse d'analogues d'intérêt / Reduction of pyridines for the preparation of chiral building-blocks : imidazole based peptidomimetics : synthesis and application to the synthesis of biologically interesting analogues

Petit, Sylvain 10 December 2010 (has links)
Deux sujets indépendants ont été traités dans ce manuscrit.Dans une première partie a été étudiée la possibilité d'obtenir des synthons chiraux à partir de la pyridine. Pour cela nous avons dans un premier temps développé une méthode originale de quaternisation des sels de pyridium et d'imidazoliums grâce à une réaction de Mitsonubu. Par la suite, des 2-aminopyridines ont été substituées puis engagées dans une réaction de quaternisation-réduction conduisant à des composants saturés. Malheureusement, des composés n'ont pu conduire aux synthons linéaires envisagés.Dans une seconde partie, nous nous sommes intéressés au développement d'un nouveau type de peptidomimétique dans lequel le lien amide est remplacé par un cycle imidazolique, ceci dans la continuité de travaux menés dans notre équipe. Dans un premier temps, nous nous sommes focalisés sur la mise au point de conditions efficaces menant au mime considéré. Cette méthodologie nous a permis la synthèse de plusieurs dipeptides. / Two different topics will be discussed in this work.In the first part has been studied the possibility to obtain chiral building-blocks from pyridine. For this purpose, we intially developed an original method for quartenization of pyridium and imidazolium salts through a Mitsonubu reaction. Then, 2-aminopyridines were substituted and then engaged in a quaternization-reduction reaction, leading to satured compounds. Unfortunately, these compounds have not leaded to targeted linear building-blocks.In a second part, we have been interested in the deveopment of a new peptidomimetic family in which the amide bond is replaced by an imidazole ring, extension of previous work in our research group. Initially we focused on the development of conditions leading to considered mimic. This methodology has allowed us the synthesis of several dipetides incorporating our mimic with good results. The determination of acido-basic properties of these structures has also been investigated.
2

POLÍMERO ANTIMICROBIANO [QAMP] PARA INCORPORAÇÃO EM SISTEMA ADESIVO ODONTOLÓGICO: DESENVOLVIMENTO, CARACTERIZAÇÃO FÍSICO-QUÍMICA, AVALIAÇÃO DA PERMEABILIDADE VASCULAR E PROPRIEDADES MECÂNICAS / Antimicrobial polymer [QAMP] for incorporation into dental adhesive system: development, physicochemical characterization, evaluation of vascular permeability and mechanical properties

Pupo, Yasmine Mendes 17 May 2013 (has links)
Made available in DSpace on 2017-07-24T19:22:33Z (GMT). No. of bitstreams: 1 YASMINE M PUPO.pdf: 8545137 bytes, checksum: 4a5dc17fead5ffe17a36e9b6d7acb198 (MD5) Previous issue date: 2013-05-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The use of bioactive restorative materials, with the ability to reduce biofilm development and to present direct action against cariogenic microorganisms, has grown in the dental market and a trend in Adhesive Dentistry. This study aims to describe the synthesis, the characterization, the antimicrobial properties, the vascular permeability and the mechanical properties of the quaternary ammonium methacrylate polymer [QAMP], for incorporation into dental adhesive systems, in order to provide increase the durability of dental restorations. QAMP was obtained through chemical modification (alkylation) of a preformed polymer [Eudragit™ E100] and n-octyl bromide. The resulting product [QAMP] was characterized by infrared spectroscopy, Raman spectroscopy, Nuclear Magnetic Resonance spectroscopy, Visible spectrophotometry, X-ray diffraction and thermogravimetric analysis (TGA). The in vitro susceptibility testing against Streptococcus mutans of QAMP was performed prior and after incorporation into a commercial adhesive system (Clearfil™ SE Bond). Clearfil™ Protect Bond containing antimicrobial standard [MDPB] and Clearfil™ SE Bond without QAMP were used as positive and negative controls, respectively. To evaluate percentage of quaternary ammonium compound released from the experimental adhesive system a test was conducted, after intervals of predetermined time (1, 7, 14, 21 and 30 days). Spectroscopic data confirmed that QAMP was successfully acquired. Thermal analysis indicated that QAMP was heat-stable. The antimicrobial effect against the Streptococcus mutans, prior and after incorporation in a dental adhesive system, was proven. The release of the quaternary ammonium compound [QAMP], embedded in an adhesive system, was reduced when compared to the commercial product [MDPB]. Additionally, the effect of Clearfil™ SE Bond containing QAMP on the vascular permeability using Evans blue and laser!"!Doppler flowmetric methods was investigated in order to define the influence on the exudative phase of the inflammatory process in the subcutaneous tissue of rats. Results support that the adhesive system containing QAMP had lower effect on this phase indicating an adequate biocompatibility. In an attempt to determine the stability of QAMP, the bond strength of adhesive systems was evaluated in extracted human teeth through microtensile test immediately, after 6 and 12 months of storage of the stick-shaped specimens. The degree of conversion of the bonding interfaces was investigated, using micro-Raman spectroscopy, and in vitro by infrared Fourier Transform. Data obtained confirm that a self-etching adhesive system with the quaternary ammonium methacrylate polymer [QAMP] could produce the effective bond strength under in vitro conditions and stability of the degree of conversion in situ and in vitro. In the evaluation of mechanical properties, hardness and elastic modulus, slices of restored teeth were prepared with adhesives under study and were submitted to artificial methods for producing caries lesions during, pH-cycling or microbiological assay, for subsequent nanoindentation test performed in the region of the interface resin-dentin, leading to check the quality of the formed substrate. In general, Clearfil™ SE Bond containing QAMP provided better mechanical properties for the resin-dentin interface than other commercial selfetching adhesives after cariogenic challenges. These data include the development of quaternary ammonium polymers to provide additional benefits for dental adhesive systems widely used in dentistry. / A utilização de materiais restauradores bioativos, com capacidade de reduzir o desenvolvimento do biofilme e de apresentar ação direta contra microrganismos cariogênicos, tem crescido dentro do mercado odontológico, sendo uma tendência na Odontologia Adesiva. O presente estudo teve como objetivo descrever a síntese, a caracterização e as propriedades antimicrobianas, de permeabilidade vascular e mecânicas de um polímero metacrílico quaternário de amônio [QAMP], quando incorporado em sistemas adesivos odontológicos, com o propósito de aumentar a durabilidade das restaurações dentais. QAMP foi obtido por modificação química (alquilação) de um polímero pré-formado [Eudragit E100] com brometo de n-octila. O produto resultante [QAMP] foi caracterizado por espectroscopia na região do infravermelho, espectroscopia Raman, espectroscopia de Ressonância Magnética Nuclear, espectrofotometria na região do visível, difração de raios X e análise termogravimétrica (TGA). O teste de susceptibilidade in vitro da cepa de Streptococcus mutans frente ao QAMP foi realizado antes e após a incorporação no sistema adesivo Clearfil SE Bond. Clearfil Protect Bond, o qual contém um antimicrobiano padrão [MDPB] e Clearfil SE Bond sem QAMP foram usados como controles positivo e negativo, respectivamente. Realizou-se também a avaliação da porcentagem de liberação do composto quaternário de amônio a partir do sistema adesivo em estudo, após intervalos de tempo prédeterminados (1, 7, 14, 21 e 30 dias). Os dados espectroscópicos confirmaram que QAMP foi obtido com sucesso. A análise térmica indicou que QAMP foi estável ao calor. O efeito antimicrobiano contra Streptococcus mutans, antes e após a incorporação ao sistema adesivo odontológico, foi comprovado. A liberação de compostos quaternários de amônio do sistema adesivo em estudo foi muito reduzida, quando comparada ao do produto comercial [MDPB]. Além ! *+! disso, investigou-se o efeito de Clearfil® SE Bond contendo QAMP sobre a permeabilidade vascular usando os métodos de azul de Evans e fluxometria por laser-Doppler a fim de avaliar a influência sobre a fase exsudativa do processo inflamatório no tecido subcutâneo de ratos. Resultados confirmam que o sistema adesivo contendo QAMP teve um menor efeito sobre esta fase, o que é indicativo de uma adequada biocompatibilidade. Na tentativa de cercar a estabilidade do QAMP foram avaliadas a resistência de união dos sistemas adesivos em estudo em dentes humanos extraídos, por meio do ensaio de microtração imediatamente, após 6 e 12 meses de armazenamento dos espécimes em forma de palitos. O grau de conversão in situ por análise micro- Raman da interface adesiva estabelecida por esses sistemas e in vitro por espectroscopia de infravermelho com Transformada de Fourier também foram avaliados. Dados obtidos confirmaram que o sistema adesivo autocondicionante com QAMP produz uma resistência de união eficaz sob condições in vitro e estabilidade do grau de conversão in situ e in vitro. Na avaliação das propriedades mecânicas, dureza e módulo de elasticidade, foram preparados dentes restaurados com os adesivos em estudo, sendo submetidos à indução de lesões artificiais de cárie por meio de ciclagem de pH e de cárie microbiológica. Posteriormente, os dentes foram cortados e as fatias submetidas ao teste de nanoindentação na região da interface de união resinadentina, conduzindo a verificação da qualidade do substrato formado. Em geral, Clearfil® SE Bond contendo QAMP proporcionou melhores propriedades mecânicas da interface resina-dentina do que outros adesivos autocondicionantes comerciais após desafios cariogênicos. Esses dados contemplam o desenvolvimento de polímeros quaternários de amônio para fornecer benefícios adicionais para os sistemas adesivos dentais amplamente utilizados em Odontologia.
3

An Efficient Rechargeable Aluminium–Amine Battery Working Under Quaternization Chemistry

Wang, Gang, Dmitrieva, Evgenia, Kohn, Benjamin, Scheler, Ulrich, Liu, Yannan, Tkachova, Valeriya, Yang, Lin, Fu, Yubin, Ma, Ji, Zhang, Panpan, Wang, Faxing, Ge, Jin, Feng, Xinliang 19 April 2024 (has links)
Rechargeable aluminium (Al) batteries (RABs) have long-been pursued due to the high sustainability and three-electron-transfer properties of Al metal. However, limited redox chemistry is available for rechargeable Al batteries, which restricts the exploration of cathode materials. Herein, we demonstrate an efficient Al–amine battery based on a quaternization reaction, in which nitrogen (radical) cations (R3N*+ or R4N+) are formed to store the anionic Al complex. The reactive aromatic amine molecules further oligomerize during cycling, inhibiting amine dissolution into the electrolyte. Consequently, the constructed Al–amine battery exhibits a high reversible capacity of 135 mAhg1 along with a superior cycling life (4000 cycles), fast charge capability and a high energy efficiency of 94.2%. Moreover, the Al–amine battery shows excellent stability against selfdischarge, far beyond conventional Al–graphite batteries. Our findings pave an avenue to advance the chemistry of RABs and thus battery performance.
4

Synthèse et caractérisation de nouveaux polymères à structures norbornadiène et triazolium pour le stockage et la conversion de l'énergie / New polymers containing norbornadiene or triazolium structures for energy storage and conversion

Abdelhedi Miladi, Imen 12 December 2014 (has links)
L'objectif de cette thèse est d'appliquer la réaction de cycloaddition-1,3-dipolaire catalysée par le Cu(I) entre un alcyne et un azoture (CuAAC) pour la synthèse de nouveaux polymères utilisables pour le stockage d'énergies alternatives. Dans une première partie, la polyaddition par CuAAC de type AA+BB a été étudiée à partir de plusieurs monomères difonctionnels afin d'obtenir des poly(1,2,3-triazole)s à structures norbornadiènes. Grâce à un réarrangement structural régi par une irradiation photochimique, le norbornadiène au sein du polytriazole est transformé en quadricyclane qui est une molécule capable de stocker l'énergie solaire. Dans une deuxième partie des polymères linéaires à motif 1,2,3-triazole ont été obtenus à partir de monomères hétérofonctionnels α-azoture-ω-alcyne. La modification chimique post-polymérisation de ces poly(1,2,3-triazole)s (quaternisation du noyau 1,2,3-triazole suivie d'un échange anionique) a permis d'obtenir de nouveaux poly(liquide ionique)s à base 1,2,3-triazolium (TPILs). Différents TPILs ont été obtenus et leurs propriétés de conductivité ionique ont été étudiées par spectroscopie diélectrique. Enfin, la synthèse d'un poly(1,2,3- triazolium) photoréticulable a permis, lors d'un processus de photolithographie, de servir en tant que résine photosensible à tonalité négative ce qui a conduit pour la première fois à la structuration d'électrolytes solides à l'échelle du micron / The present work aims at elaborating new polymers by copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) step growth polymerization suited for the storage of alternative energies. In a first part, the AA+BB CuAAC polyaddition has been investigated using several difunctional monomers to prepare norbornadiene-containing poly(1,2,3-triazole)s. The norbornadiene units present in the main chain of these polymers are isomerized after UVirradiation into quadricyclane units able to store solar energy. In a second part, other linear poly(1,2,3-triazole)s were prepared from α-azide-ω-alkyne heterofunctional monomers. The post-polymerization chemical modification of these poly(1,2,3-triazole)s (quaternization of the 1,2,3-triazole units followed by anion metathesis reaction) resulted in new 1,2,3-triazolium-based poly(ionic liquid)s (TPILs). Various TPILs were obtained and their ionic conductivity properties were studied by dielectric spectroscopy. Finally, a UV-crosslinkable poly(1,2,3-triazolium) was synthesized and was used as a negative tone photoresist for lithography thus affording the efficient patterning of solid electrolytes
5

Iontové polymery a polymerní sítě polyacetylenického typu připravené metodou kvaternizační polymerizace / Ionic polyacetylene type polymers and polymer networks by catalyst-free quaternization polymerization

Faukner, Tomáš January 2016 (has links)
(Doctoral Thesis, 2016, Mgr. Tomáš Faukner, IONIC POLYACETYLENE TYPE POLYMERS AND POLYMER NETWORKS BY CATALYST FREE QUATERNIZATION POLYMERIZATION) The composition and structure of a series of ionic π-conjugated poly(monosubstituted acetylene)s prepared via catalyst-free quaternization polymerization (QP) of 2-ethynylpyridine (2EP) activated with equimolar amount of alkyl halide [RX = ethyl bromide, ethyl iodide, nonyl bromide and haxadecyl (cetyl) bromide] as a quaternizing agent (QA) have been studied in detail. The performed QPs gave ionic polymers well soluble in polar solvents, with approximately half of pyridine rings quaternized, which implies that also non-quaternized monomers were involved in the process of QP. The configurational structure of polyacetylene main chains was suggested based on 1 H NMR, IR as well as Raman (SERS) spectral methods. The QPs in bulk gave more expected irregular cis/trans polymers while the QPs in acetonitrile solution gave high-cis polymers. A series of prepared symmetrical bi-pyridylacetylene based monomers has been polymerized via QP approach resulting into a series of new ionic π-conjugated poly(disubstituted acetylene) type materials. It is therefore obvious that the mechanism of quaternization activation frequently applied on monosubstituted...
6

Funkcionalizované mikroporézní polymerní sítě připravené z ethynylarenů / Functionalized microporous polymer networks prepared from ethynylarenes

Stahlová, Sabina January 2016 (has links)
The preparation of a new group of functionalized conjugated polymer networks has been described based on spontaneous quaternization polymerization of ethynylpyridines with bis(bromomethyl)arenes. The networks consisted of polyacetylene chains with pyridyl and pyridiniumyl pendants cross-linked with -CH2(arylene)CH2- links. The variation of the ratio of monomer and quaternization agent in the feed modified the ratio of pyridyl and pyridiniumyl groups in the networks (pyridyl/pyridiniumyl ratios from 0 to 1.32). The networks did not exhibit a permanent microporosity that could be confirmed by nitrogen adsorption at 77 K. Nevertheless, all networks were active in capture of CO2 at 293 K (up to 0.73 mmol CO2/g, 750 Torr). It has been hypothesized that CO2 capture reflected formation of a temporary porous texture of the networks through conformational changes of the network segments enabled by the segments mobility at room temperature. The preparation of functionalized conjugated polymer networks with permanent micro/mesoporosity (SBET up to 667 m2 /g) has been described that was based on chain coordination copolymerization of acetylenic monomers. The copolymerization of 1,4-diethynylbenzene or 4,4'-diethynylbiphenyl with mono or diethynylbenzenes bearing NO2 or CH2OH groups has been demonstrated as...

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