Estudo quantitativo da reatividade de compostos organometalicos de metais de transição

AUTOR(ES)
DATA DE PUBLICAÇÃO

1977

RESUMO

Despite the enormous number of studies of organo-metallic complexas of the sandwich type, many aspects of their chemistry remain to be clarified. These include the mechanisms of the reactions; and the participation of -orbitals in the bonding between the ligand and the central atom. Since reactivity measurements are a powerful tool in chemical investigations, we have studied quantitatively some substitution reactions of the cationic arene-complexes (CIC6H5FeC5H5) BF4 and (p-Cl2C6H4FeC5H5) BF4. These substrates were synthetised by methods previously described in the literature, and their structures confirmed by the usual methods. Sodium thiophenoxide, sodium. azide and sodium sulphite, aniline, urea and thiourea were used as nucleophiles with the mono-cloro complex, the results being compared with these obtained with sodium methoxide. The latter reagent was used wi th the di-chIoro complex. With the exception of the sulphite reactions, alI the measurements were made with anhydrous methanol as solvent. Due to the low solubility of sodium sulphite in this solvent, its reactions were carried out in a mixture of methanol-water (60:40 v/v). Because of the facile oxidation of the complexes, both syntheses and rate studies were carried out under a nitrogen atmosphere. The rate constants (k2) at various temperature and kinetic parameters, were obtained by following the chloride displaced, using potentiometric titrations, in aliquots compared with data for selected aromatic substrates, not bonded to metal atoms; as well as some other organo-metallic complexes.

ASSUNTO(S)

reatividade (quimica) compostos de metais de transição compostos organometalicos

ACESSO AO ARTIGO

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