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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

Investigação comparativa da liberação controlada de CO e NO por carboxilatos trinucleares de rutênio contendo ligantes pi-receptor e sigma-doador / Comparative investigation of the controlled release of CO and NO by ruthenium trinuclear carboxylates containing pi-receptor ligands and sigma-donor

Silva, Camila Fontes Neves da 23 February 2015 (has links)
Neste trabalho foram realizadas as sínteses e caracterizações dos precursores (1) [Ru3O(CH3COO)6(CH3OH)3]CH3COO, (2) [Ru3O(CH3COO)6(CO)(CH3OH)2] (3) [Ru3O(CH3COO)6(4-acpy)2(H2O)]PF6, (4) [Ru3O(CH3COO)6(4-tbpy)2(H2O)]PF6 e dos complexos inéditos (5) [Ru3O(CH3COO)6(4-acpy)2(CO)], (6) [Ru3O(CH3COO)6(4-tbpy)2(CO)], (7) [Ru3O(CH3COO)6(4-acpy)2(NO)]PF6, (8) [Ru3O(CH3COO)6(4-tbpy)2(NO)]PF6. Os complexos foram caracterizados por espectroscopia na região do UV-Vis e do infravermelho, espectroscopia de ressonância magnética nuclear (RMN), voltametria cíclica e análise elementar. Por meio dos resultados obtidos nas técnicas de caracterização, foi possível confirmar a estrutura proposta inicialmente para os complexos e também para os precursores. Além disso, também foi possível observar a influência dos ligantes, -receptor e -doador na estrutura dos mesmos. Por meio da técnica de espectroscopia de infravermelho analisou-se principalmente estiramentos dos ligantes CO nos complexos 5 e 6 e do NO nos complexos 7 e 8. Nos estudos de RMN observou-se as características diamagnéticas dos complexos 5 e 6, e no caso dos complexos 7 e 8 foi possível confirmar que há uma forte interação entre o elétron desemparelhado na unidade [Ru3O]+ e do ligante NO0. Os ensaios eletroquímicos de voltametria cíclica mostraram a influência dos ligantes CO e NO na comunicação eletrônica da unidade [Ru3O].Os complexos com ligantes CO e NO foram irradiados com laser em 377 nm e 660 nm em soluções de acetonitrila e tampão fosfato pH 7,4. Estas irradiações foram acompanhadas por espectroscopia na região do UV-visível. No caso dos complexos 5 e 6, o aumento da banda na região de 900 nm indicou a formação do complexo, [Ru3O(CH3COO)6(L)2(S)], após a liberação do ligante monóxido de carbono (CO). A liberação de CO ocorreu predominantemente com irradiação em 377 nm na região do ultravioleta em pH fisiológico (solução aquosa de tampão fosfato, pH=7,4) e também em solução de acetonitrila. Para os complexos com ligantes NO, o perfil espectral obtido após fotólise indicou a formação de um complexo oxidado sem a coordenação do NO, [Ru3O(CH3COO)6(L)2(S)]+. / In this study it was performed the synthesis and characterization of the precursors (1) [Ru3O(CH3COO)6(CH3OH)3]CH3COO, (2) [Ru3O(CH3COO)6(CO)(CH3OH)2] (3) [Ru3O(CH3COO)6(4-acpy)2(H2O)]PF6 (4) [Ru3O(CH3COO)6(4-tbpy)2(H2O)]PF6 and the unpublished complexes (5) [Ru3O(CH3COO)6(4-acpy)2(CO)] (6) [Ru3O(CH3COO)6(4-tbpy)2(CO)] (7) [Ru3O(CH3COO)6(4-acpy)2(NO)]PF6 (8) [Ru3O(CH3COO)6(4-tbpy)2(NO)]PF6. The complexes were characterized by UV-Vis and infrared spectroscopy, nuclear magnetic resonance (NMR), cyclic voltametry, and elemental analysis. By means of the results obtained from the characterization, it was possible to confirm the initially proposed structure for both complexes and precursors. Furthermore, it was also possible to observe the influence of ligands, - receptor and the -donor in the structure of the complexes. By infrared spectroscopy it was verified primarily stretches of the CO and NO ligands in complexes 5,6 and 7,8 respectively. In NMR it was observed the diamagnetic character of complexes 5 and 6, and in the case of complexes 7 and 8 it was confirmed that there is a strong interaction between the unpaired electron in the [Ru3O]+ unit and the NO0 ligand. The cyclic voltammograms showed the influence of the CO and NO ligands on the electronic communication of the [Ru3O] unit. Complexes with ligands CO and NO were irradiated with laser at 377 nm and 660 nm in solutions of acetonitrile and phosphate buffer pH 7.4. The photolysis were accompanied by spectroscopy in the UV-visible region. In the case of complexes 5 and 6, the increase of the band in the region of 900 nm indicated the formation of the complex, [Ru3O(CH3COO)6(L)2(S)]+ produced after release of carbon monoxide (CO). The release of CO occurs predominantly with irradiation at 377 nm in the ultraviolet region at physiological pH (aqueous phosphate buffer solution, pH = 7.4) and in acetonitrile solution. For complexes with NO ligands, the spectral profile obtained after photolysis indicated the formation of an oxidized complex without coordination of NO, the [Ru3O(CH3COO)6(L)2(S)] + molecule.
2

Investigação comparativa da liberação controlada de CO e NO por carboxilatos trinucleares de rutênio contendo ligantes pi-receptor e sigma-doador / Comparative investigation of the controlled release of CO and NO by ruthenium trinuclear carboxylates containing pi-receptor ligands and sigma-donor

Camila Fontes Neves da Silva 23 February 2015 (has links)
Neste trabalho foram realizadas as sínteses e caracterizações dos precursores (1) [Ru3O(CH3COO)6(CH3OH)3]CH3COO, (2) [Ru3O(CH3COO)6(CO)(CH3OH)2] (3) [Ru3O(CH3COO)6(4-acpy)2(H2O)]PF6, (4) [Ru3O(CH3COO)6(4-tbpy)2(H2O)]PF6 e dos complexos inéditos (5) [Ru3O(CH3COO)6(4-acpy)2(CO)], (6) [Ru3O(CH3COO)6(4-tbpy)2(CO)], (7) [Ru3O(CH3COO)6(4-acpy)2(NO)]PF6, (8) [Ru3O(CH3COO)6(4-tbpy)2(NO)]PF6. Os complexos foram caracterizados por espectroscopia na região do UV-Vis e do infravermelho, espectroscopia de ressonância magnética nuclear (RMN), voltametria cíclica e análise elementar. Por meio dos resultados obtidos nas técnicas de caracterização, foi possível confirmar a estrutura proposta inicialmente para os complexos e também para os precursores. Além disso, também foi possível observar a influência dos ligantes, -receptor e -doador na estrutura dos mesmos. Por meio da técnica de espectroscopia de infravermelho analisou-se principalmente estiramentos dos ligantes CO nos complexos 5 e 6 e do NO nos complexos 7 e 8. Nos estudos de RMN observou-se as características diamagnéticas dos complexos 5 e 6, e no caso dos complexos 7 e 8 foi possível confirmar que há uma forte interação entre o elétron desemparelhado na unidade [Ru3O]+ e do ligante NO0. Os ensaios eletroquímicos de voltametria cíclica mostraram a influência dos ligantes CO e NO na comunicação eletrônica da unidade [Ru3O].Os complexos com ligantes CO e NO foram irradiados com laser em 377 nm e 660 nm em soluções de acetonitrila e tampão fosfato pH 7,4. Estas irradiações foram acompanhadas por espectroscopia na região do UV-visível. No caso dos complexos 5 e 6, o aumento da banda na região de 900 nm indicou a formação do complexo, [Ru3O(CH3COO)6(L)2(S)], após a liberação do ligante monóxido de carbono (CO). A liberação de CO ocorreu predominantemente com irradiação em 377 nm na região do ultravioleta em pH fisiológico (solução aquosa de tampão fosfato, pH=7,4) e também em solução de acetonitrila. Para os complexos com ligantes NO, o perfil espectral obtido após fotólise indicou a formação de um complexo oxidado sem a coordenação do NO, [Ru3O(CH3COO)6(L)2(S)]+. / In this study it was performed the synthesis and characterization of the precursors (1) [Ru3O(CH3COO)6(CH3OH)3]CH3COO, (2) [Ru3O(CH3COO)6(CO)(CH3OH)2] (3) [Ru3O(CH3COO)6(4-acpy)2(H2O)]PF6 (4) [Ru3O(CH3COO)6(4-tbpy)2(H2O)]PF6 and the unpublished complexes (5) [Ru3O(CH3COO)6(4-acpy)2(CO)] (6) [Ru3O(CH3COO)6(4-tbpy)2(CO)] (7) [Ru3O(CH3COO)6(4-acpy)2(NO)]PF6 (8) [Ru3O(CH3COO)6(4-tbpy)2(NO)]PF6. The complexes were characterized by UV-Vis and infrared spectroscopy, nuclear magnetic resonance (NMR), cyclic voltametry, and elemental analysis. By means of the results obtained from the characterization, it was possible to confirm the initially proposed structure for both complexes and precursors. Furthermore, it was also possible to observe the influence of ligands, - receptor and the -donor in the structure of the complexes. By infrared spectroscopy it was verified primarily stretches of the CO and NO ligands in complexes 5,6 and 7,8 respectively. In NMR it was observed the diamagnetic character of complexes 5 and 6, and in the case of complexes 7 and 8 it was confirmed that there is a strong interaction between the unpaired electron in the [Ru3O]+ unit and the NO0 ligand. The cyclic voltammograms showed the influence of the CO and NO ligands on the electronic communication of the [Ru3O] unit. Complexes with ligands CO and NO were irradiated with laser at 377 nm and 660 nm in solutions of acetonitrile and phosphate buffer pH 7.4. The photolysis were accompanied by spectroscopy in the UV-visible region. In the case of complexes 5 and 6, the increase of the band in the region of 900 nm indicated the formation of the complex, [Ru3O(CH3COO)6(L)2(S)]+ produced after release of carbon monoxide (CO). The release of CO occurs predominantly with irradiation at 377 nm in the ultraviolet region at physiological pH (aqueous phosphate buffer solution, pH = 7.4) and in acetonitrile solution. For complexes with NO ligands, the spectral profile obtained after photolysis indicated the formation of an oxidized complex without coordination of NO, the [Ru3O(CH3COO)6(L)2(S)] + molecule.
3

Evaluation of The Electronic Properties of Carbon(0)-Based Compounds Through Gold Catalysis and X-Ray Structure Analysis / Évaluation des propriétés électroniques des composés à base de carbone(0) par la catalyse a l’or et analyse des structures aux rayons-X.

El hellani, Ahmad 23 November 2012 (has links)
La plupart des composés organiques ont un atome de carbone tétravalent, où tous les électrons de valence sont utilisés pour former des liaisons covalentes. En parallèle, la chimie des composés divalents ayant un carbone(II) s’est développée après l’isolement de carbènes stables par Bertrand en 1985. Auparavant, en 1961, Ramirez a rapporté l’isolement de l’hexaphénylcarbodiphosphorane, que l’on peut considérer comme un composé présentant un carbone(0) avec ses deux doublets libres, lui permettant de coordiner jusqu’à deux acides de Lewis. A partir de 2006, les propriétés électroniques de ces ligands ont été étudiées au travers d’études théoriques par Frenking ; ce qui a permis à Bertrand et Fürstner d’isoler et d’ajouter des nouveaux membres à cette famille. Cette classe de ligand est aujourd’hui connue sous le nom de “carbônes”, avec comme formule générale CL2 (L = PR3 ou carbène).Cette famille n’a jamais été utilisée dans le domaine de la catalyse. C’est pourquoi nous avons, décidé d’etudier les propriétés électroniques de ce ces composés au travers de la catalyse à l’or, afin de les comparer aux NHC, phosphines, et phosphites. Récemment, nous avons utilisé ces composés pour générer des complexes donneur accepteur avec du GaCl3, et de corréler leurs différentes caractéristiques géometriques à leurs propriétés électroniques en utilisant les règles de Gutmann sur des adduits acide/base de Lewis. De plus, nous avons isolé des “dimères” ioniques dont la formation peut être expliquée par les propriétés intrinsèques des ligands. Nous avons ainsi démontré par ces deux approches que les “carbônes” sont de meilleurs donneurs que les NHC. / Most organic compounds which are stable in the condensed phase contain tetravalent carbon atoms, where all four valence electrons are being engaged in chemical bonds. On the other hand, the chemistry of divalent carbon(II) was only recognized after the isolation of a stable persistent carbene by Bertrand and co-workers in 1985. Such products display one s-type lone pair orbital and are thus good ligands. Earlier on, concern was also paid to a new family of compounds, first reported in 1961 by Ramirez and co-workers. They can be considered as divalent carbon(0) derivatives with two lone pairs at the central carbon, with a possibility of double coordination of two Lewis acids to this carbon. This feature was proposed by Kaska in 1973, and verified later by the isolation of di-metalated adducts. From 2006, these compounds were the centre of extensive theoretical investigations by Frenking, which led to the isolation of new members of this family by Fürstner and Bertrand. This family is now referred to as “carbones”, of general formula CL2 (L =PR3 or carbene).“Carbones” are still virtually unused in catalysis. Thus, we have decided to study these derivatives, especially in the field of gold catalysis, and to compare them with well-known ligands such as NHCs, phosphines and phosphites. Recently, we were able to synthesize their corresponding GaCl3 complexes and to rationalize their electronic properties through Gutmann’s rules for Lewis acid/Lewis base adducts. In addition, we obtained some ionic “dimers” and we explained their formation on the basis of ligand’s electronic properties. We have shown through these two approaches that carbones are far better donors than NHCs.

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