SciELO - Scientific Electronic Library Online

vol.17 número7Analysis of liquid stevioside and cyclamate-saccharin dietetic sweeteners by inductively coupled plasma optical emission spectrometry without sample treatmentTotal and methyl mercury in different species of molluscs from two estuaries in Rio de Janeiro State índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados




Links relacionados


Journal of the Brazilian Chemical Society

versión impresa ISSN 0103-5053versión On-line ISSN 1678-4790


CARVALHO, Luciana B. et al. Autoxidation of Ni(II) and Co(II) tetra, penta and hexaglycine complexes accelerated by oxy sulfur radicals. J. Braz. Chem. Soc. [online]. 2006, vol.17, n.7, pp.1400-1408. ISSN 0103-5053.

The autoxidation of Ni(II) and Co(II) complexes with tetra, penta and hexaglycine, in borate medium, is accelerated by sulfur(IV) species (H2SO3, HSO3- and SO32-). The formation of Ni(III) and Co(III) complexes was followed spectrophotometrically at 325 and 265 nm, respectively. Electrochemical techniques were also employed to characterize the generation of these complexes. The autoxidation rate increases with S(IV) concentration and is maximum at pH @ 8.5. The process is autocatalytic with Ni(III) or Co(III) acting as initiators, formed by spontaneous oxidation by oxygen. The dependence of the pseudo first order rate constant with sulfite concentration showed evidences of back or parallel reactions with formation of mixed ligand complex prior to the oxidation step.

Palabras clave : nickel; cobalt; pentaglycine; hexaglycine; sulfite.

        · resumen en Portugués     · texto en Inglés     · Inglés ( pdf epdf )


Creative Commons License Todo el contenido de esta revista, excepto dónde está identificado, está bajo una Licencia Creative Commons