| Abstract: | The complex species formed in aqueous solution (25 ∘C, I = 3.0 mol-dm−3 KCl ionic medium) between V3+ cation and the ligands: picolinic acid (Hpic, HL) and dipicolinic acid (H2dipic, H2L), have been studied potentiometrically and by spectrophotometric measurements. The application of the least-squares computer program LETAGROP to the experimental emf (H) data, taking into account the hydrolytic species of V3+ ion, indicates that under the employed experimental conditions, the formation of the complexes VL]2+, V(OH)L]+, VL2]+, VL3], V2OL4] with picolinic acid and the complexes VL]+, V(OH)L], V(OH)2L]−, V(HL)(L)], and VL2]− with dipicolinic acid were observed. The stability constants of the complexes formed were determined by potentiometric measurements, and spectrophotometric measurements were done in order to perform a qualitative characterization of the complexes formed in aqueous solution. |
