Estudos de complexos metálicos de Rutênio com ligantes o-fenilênicos e o ligante bifosfínico: 1,4-bis(difenilfosfino) butano (dppb)

• Ano de defesa: 2007
• Autor(a) principal: Silva, Ana Lúcia Rodrigues da
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Química de coordenação; Bifosfinas; Catecol; Quinona
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/1023

This research work describes the synthesis, characterization, reactivity and properties of new complexes of ruthenium with the ligands o-phenylenediamine, oaminophenol, catechol, naphtalenediol, dopamine and adrenaline and the mer-[RuIIICl3(dppb)(H2O)] complex. Also, it describes a new metal-assisted oxidative dehydrogenation of the interaction o-phenylenediamine ligand and the mer- [RuIIICl3(dppb)(H2O)] complex. The mer-[RuIIICl3(dppb)(H2O)] complex has shown to be a versatile compound as starting material. The reaction of this compound with the o-phenylenediamine ligand produced a mixture of compounds with the bqdi and opda forms of the o-phenylene ligand, the trans-[RuIICl2(dppb)(bqdi)] and trans-[RuIICl2(dppb)(opda)] complexes, that it was confirmed for the observation of two singlet signals at d 47 and d 26 in the 31P{1H} NMR spectrum. One very first assignment suggests that the opda ligand is oxidized to bqdi form during the reaction, according to mechanism proposed in this work. However, the product of the reaction between the o-phenylenediamine ligand and the mer-[RuIIICl3(dppb)H2O] complex by the slow addition of the ligand showed only one signal at d 26 in the 31P{1H} NMR spectrum, indicating that the trans-[RuIICl2(dppb)(bqdi)] complex is preferentially produced. This complex was characterized by the elemental analysis, spectroscopic and electrochemical techniques and its structure has been determined by X-ray crystallography. Aiming to reinforce the proposed mechanism, we conducted the reaction of the o-phenylenediamine ligand with the [RuIICl2(dppb)(PPh3)] complex. Since the ruthenium metal center is already in the reduced state, it will not promote any redox change in the ligand. Thus, the complex produced showed only one signal at d 26 in the 31P{1H} NMR spectrum, indicating the formation of the trans-[RuIICl2(dppb)(opda)] complex that it was characterized by the elemental analysis, spectroscopic and electrochemical techniques and its structure has been determined by X-ray crystallography. The compounds isolated of type trans-[RuIICl2(dppb)(X)], X = quinone, dopamine and adrenaline and cis-[RuIICl2(dppb)(L)], L = o-aminophenol in the quinonoide form and bqdi, were characterized by the spectroscopic and electrochemical techniques.