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Master's Dissertation
DOI
https://doi.org/10.11606/D.59.2015.tde-23052015-113643
Document
Author
Full name
Camila Fontes Neves da Silva
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2015
Supervisor
Committee
Nikolaou, Sofia (President)
Alexiou, Anamaria Dias Pereira
Silva, Roberto Santana da
Title in Portuguese
Investigação comparativa da liberação controlada de CO e NO por carboxilatos trinucleares de rutênio contendo ligantes pi-receptor e sigma-doador
Keywords in Portuguese
Carboxilatos trinucleares de rutênio
Ligantes pi-receptor e sigma-doador
Monóxido de carbono
Óxido nítrico
Abstract in Portuguese
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)]+.
Title in English
Comparative investigation of the controlled release of CO and NO by ruthenium trinuclear carboxylates containing pi-receptor ligands and sigma-donor
Keywords in English
carbon monoxide
nitric oxide
pi-acceptor and sigma-donor ligands
trinuclear ruthenium carboxylates
Abstract in English
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.
 
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Publishing Date
2015-07-16
 
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