Article
Formation constants for the ternary complexes of vanadium(III), 8-hidroxyquinoline, and the amino acids histidine, cysteine, aspartic and glutamic acids
Autor
Guzmán D., Luis A.
Martínez, José Daniel
Araujo, Mary Lorena
Brito, Felipe
Del Carpio, Edgar
Hernández, Lino
Lubes, Vito
Institución
Resumen
Solution equilibria of V(III)-8-hydroxyquinoline (H8HQ) and aspartic acid (H2Asp), glutamic acid (H2Glu), cysteine
(H2Cys) and histidine (HHis) ternary systems, have been studied through potentiometric measurements. The
formation constants of the resulting mixed ligand complexes at 25 °C were calculated using 3.0 mol·dm−3 KCl
ionic strength. The species distribution diagrams for the complexes in solution were generated considering
the formation of the [V(8HQ)(H2Asp)]2+ and V(8HQ)(Asp) complexes in the vanadium(III)–H8HQ–H2Asp system.
Several species were observed: [V(8HQ)(HGlu)]+, V(8HQ)(Glu) and [V(8HQ)(Glu)(OH)]− in the
vanadium(III)–H8HQ–H2Glu system; species; [V(8HQ)(H2Cys)]2+, [V(8HQ)(HCys)]+, V(8HQ)(Cys) and
[V(8HQ)(Cys)(OH)]− for the vanadium(III)–H8HQ–H2Cys system, and the complexes [V(H8HQ)(HHis)]4+ and
[V(8HQ)(His)]+ in the vanadium(III)–H8HQ–HHis system