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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

Bis(Diaryliodonium) Perfluorosulfonimide Zwitterions as Potential Photo Acid Generators

Mei, Hua, Desmarteau, Darryl D. 01 April 2014 (has links)
Three examples of bis(diaryliodonium) perfluorosulfonimide (BDI-PFSI) zwitterions have been prepared as a potential new class of ionic photo-acid generators for chemically amplified photoresist formulations.
2

Applications of functionnal diphosphines quinonoid zwietterions to coordination chemistry and surface functionalization / Applications de ligands diphosphines fonctionnelles et de zwitterions quinonoïdes à la chimie de coordination et à la fonctionalisation de surfaces

Ghisolfi, Alessio 20 June 2014 (has links)
Le but de ce travail de thèse était de développer de nouvelles familles de ligands polyfonctionnels pour étudier, dans un premier temps, leur chimie de coordination vis-à-vis de métaux de transition et, dans un second temps, en fonction des espèces formées, leurs propriétés physiques (magnétiques par exemple) et/ou catalytiques. L’évaluation de leur potentiel pour la formation de nouveaux matériaux ou la fonctionnalisation de supports métalliques faisait également partie intégrante des objectifs de cette thèse. De ce fait, chaque ligand a été fonctionnalisé avec des groupements adaptés à l’ancrage sur surfaces, comme des fonctions zwitterioniques ou des thio-éthers. / The aim of this thesis was to develop new families of polyfunctional ligands to study their coordination chemistry towards transition metals and, depending on the products formed, to investigate their physical (e.g. magnetic) and / or catalytic properties. The evaluation of their potential for the formation of new materials as well as for the functionalization of metal surfaces was also part of the objective of this thesis. Therefore, each ligand has been functionalized with groups suitable for the anchoring on metallic surfaces, such as zwitterionic or thioethers moieties.
3

Synthèse chimioenzymatique et évaluation d'inhibiteurs potentiels de glycosidases, analogues de la valiolamine

El Blidi, Lahssen 16 November 2006 (has links) (PDF)
Les glycosidases sont des enzymes impliquées dans un grand nombre de processus biologiques. Leurs inhibiteurs présentent un potentiel thérapeutique en tant qu'agents antidiabétiques, agents antiviraux ou agents pour traiter des maladies génétiques. Au cours de ce travail, nous nous sommes attachés à développer une voie de synthèse chimioenzymatique permettant d'accéder à des analogues de la valiolamine, puissant inhibiteurs d'alpha-glucosidases. Les aminocyclitols que nous avions pour objectif de préparer diffèrent de la valiolamine par la position du groupement amino et des stéréochimies des hydroxyles. Nous avons synthétisé ces aminocyclitols selon une méthode originale, basée sur un procédé en un seul pot mettant en jeu deux enzymes et trois réactions : une aldolisation catalysée par la fructose-1,6- biphosphate aldolase, une déphosphorylation catalysée par une phytase et une nitroaldolisation intramoléculaire. Ainsi deux liaisons C-C sont formées de façon hautement stéréosélective en une seule étape. Nous avons synthétisé neuf nouveaux aminocyclitols et deux nouveaux zwitterions et dérivé N-alkylé. Quelque aminocyclitols se sont révélés des inhibiteurs sélectifs de la béta-glucosidase d'amandes douces et de la béta-galactosidase d'Aspergillus oryzae.
4

Síntese e caracterização estrutural de polialetos e compostos zwitteriônicos derivados de diteluretos de diarila / Sinthesys and caracterization of polyalides and zwitterionic compounds starting from diaryl ditellurides

Silva, Felipe Dornelles da 22 June 2016 (has links)
The present work describes the synthesis and structural elucidation of ten new tellurium halide starting from diaryl ditellurides (aryl group = 2-piridine or N,N-dimethylbenzilamine). The compounds and starting material had their structures elucidated with monocrystal X ray diffraction and as an additional analysis another technique was used like infrared spectroscopy, Raman spectroscopy, 1H and 125Te Nuclear Magnetic Resonance and elemental analysis. Different methodologies were used to get tellurium II and tellurium IV compounds due the tellurium atom versatility which it behaved like neutral molecules and zwitterionic molecules (molecules that have an internal positive and negative charge). The compounds showed Te∙∙∙X secondary bonds or Te∙∙∙X and X∙∙∙X interactions (X = halogen atom) due to lone electron pair around the tellurium atom localization and to the tellurium-halogen affinity. In the solid state, these bonds make the compounds show a supramolecular arrangements which can be a pseudo-dimeric or pseudo-polymeric and it depends of the halogen atom attached to the tellurium atom. / O presente trabalho apresenta a síntese e caracterização estrutural de dez haletos de telúrio inéditos derivados de diteluretos de diarila (onde o grupamento arila pode ser a 2-piridina ou a N,N-dimetilbenzilamina). Os compostos tiveram sua estrutura elucidada por difração de raios X em monocristal assim como por espectroscopia vibracional na região do infravermelho, espectroscopia Raman, espectroscopia por ressonância magnética nuclear de 1H, 125Te e análise elementar. Devido à versatilidade do átomo de telúrio em alterar seu número de coordenação e oxidação, utilizou-se diferentes metodologias para obter compostos com o átomo de telúrio possuindo número de oxidação II e IV, os quais comportaram-se como moléculas neutras ou moléculas zwitteriônicas (moléculas que possuem internamente uma carga positiva e uma carga negativa). Em virtude da localização dos pares de elétrons não ligantes ao redor do átomo de telúrio e da afinidade do átomo com os elementos do grupo 17 da tabela periódica, os compostos apresentaram ligações secundárias Te∙∙∙X ou interações Te∙∙∙X e X∙∙∙X (onde X é um átomo de halogênio) e estas, fazem com que os compostos, no estado sólido, apresentem um arranjo estrutural supramolecular cujo comportamento pode ser de um pseudo-dímero ou pseudo-polímero dependendo do átomo de halogênio ligado ao átomo de telúrio.
5

Análise estrutural de complexos derivados de telúrio / Structural analysis of tellurium based complexes

Santos, Sailer Santos dos 18 March 2011 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work describes the synthesis and structural analysis of different kinds of tellurium based compounds, depicting the preparation of zwitterions, coordination polymers and also heteronuclear complexes, using 4-ditellurobispyridine (4) and N , N , N , N -tetraethyl-N,N -pyridine-2,6-dicarbonyl-bis(thiourea) (12) as starting materials. These ligands are able to form complexes with tellurium allowing the simultaneous coordination of transition metals, producing novel compounds. The materials were characterized by single crystal X-ray diffraction, vibrational spectroscopy and 1H and 125Te nuclear magnetic resonance (when applicable). The methodology using the ligand 12 provided the preparation of three different classes of compounds: complexes with inorganic tellurium, complexes with organic derivatives of tellurium and tellurium based complexes with transition metals. The later ones are the most interesting owing the selectivity of the ligand, that coordinates to tellurium just with the softer site (sulfur atom), leaving the other donor atoms free to coordinate to another metallic center. / Este trabalho apresenta a síntese e a análise estrutural de diferentes classes de complexos derivados de telúrio, com a obtenção de zwitterions, polímeros de coordenação, e também, complexos heteronucleares, a partir de ditelureto de bis-4-piridila (4) e do ligante N , N , N , N -tetraetil-N,N -piridina-2,6- dicarbonil-bis(tioureia) (12). Os ligantes utilizados neste trabalho são capazes de formar complexos com telúrio permitindo a coordenação simultânea de metais de transição, de tal modo que as metodologias de síntese empregadas são capazes de fornecer compostos inéditos na literatura. Os materiais foram caracterizados por difração de raios-X em monocristal, espectroscopia no infravermelho, análise elementar, e ressonância magnética nuclear de 1H e de 125Te nos exemplos em que as técnicas são aplicáveis. As metodologias envolvendo o ligante 12 permitiram a obtenção de três classes distintas de compostos: complexos com telúrio inorgânico, com derivados orgânicos de telúrio e complexos em combinação com metais de transição. Os complexos envolvendo metais de transição têm especial destaque, pois o ligante 12 mostrou excelente seletividade, ocorrendo a coordenação ao átomo de telúrio exclusivamente pelo sítio macio (átomo de enxofre), deixando os outros sítios doadores livres para coordenação com outro centro metálico.

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