915 resultados para Cyclic Staircase Voltammetry
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
The monomeric compound bis[(carbonyl)(quinoline-2-thiolate-N,S)]iron(II) was synthesized and studied by IR and Mossbauer spectroscopy, cyclic voltammetry and X-ray diffraction. The molecule has two terminal carbonyl groups and two quinoline-2-thiolate anions coordinated as N,S-donor chelates, and the iron atom shows an octahedral coordination geometry.
Resumo:
The cct isomers [RuCl 2(CO) 2(PPh 3) 2] (1) and [RuCl 2(CO) 2(AsPh 3) 2] (2) were synthesized from [RuCl 3(PPh 3) 2DMA]DMA and [RuCl 3(AsPh 3) 2DMA]DMA, respectively. The complexes were characterized by elemental analysis, IR and UV-vis spectroscopy and their molecular structures were found to be cis-cis-trans isomers by X-ray crystallography. Cyclic voltammetry data show that the tripenylphosphine stabilizes better the ruthernium(II) complex than the tripenylarsine ligand. © 1994.
Resumo:
The electrochemical behaviour of N-R-4-cyanopyridinium (4-rcp) (R = methyl, decyl, dodecyl, or benzyl) coordinated to pentaammineruthenium(II) in CF3COOH-CF3COONa (μ = 0.1 M, pH 3) aqueous medium was studied by means of cyclic voltammetry and constant potential electrolysis. The electrochemical oxidation of the metallic centre (Ep ca 0.51 V/SCE) can be described as a reversible monoelectronic charge-transfer followed by an irreversible chemical reaction, which is the hydrolysis of N-R-4-cyanopyridiniumpentaammineruthenium(III) (A) to N-R-4-carboxamidepyridiniumruthenium (III) (B) with the kf1 values depending on the type of alkyl group. The E 1 2 values are not significantly influenced by the nature of the alkyl group. At more negative potential (ca -0.5 V/SCE), B undergoes an electrochemical reduction followed by an aquation reaction to produce aquopentaammineruthenium(II) and free N-R-4-carboxamidepyridinium. The amide was identified by comparison of its cyclic voltammogram and UV-vis spectrum with that of a sample prepared by chemical reaction. The results were also discussed by comparison with other systems, and show that nitrile-amide conversion catalysed by pentaammineruthenium(II) complexes is possible. © 1994.
Resumo:
The electrochemical behaviour of alanine and phenylalanine protected by the toluenesulphonyl (tosyl) and nitrobenzesulphonyl (nosyl) groups was examined in dimethyl formamide. The N-tosyl-protected amino acids are reduced in one cathodic step (-2.4 V/SCE) leading to cleavage of the SN bond after a two-electron transfer process. The N-nosyl-protected amino acids are reduced in three cathodic steps. Cyclic voltammetry and controlled potential electrolysis of N-nosyl amino acids have been used to probe the mechanism of these reductions in an aprotic medium and lead to cleavage of the SN bond in good yields ( > 60%) at -1.10 V/SCE. The comparative study of these compounds is used to comment on the applicability of the electrochemical method of removing protecting groups from amino acids. © 1993.