1Iranian Research & Development Center for Chemical Industries, Jahad Daneshgahi Inst., Sharif University of Technology, Tehran I.R. IRAN
2Department of Chemistry, Shahid Beheshti University, Tehran, I.R. IRAN
3Teacher Training University, Tehran, I.R. IRAN
Formation equilibria of dioxy vanadium (V) complex with alanine in acidic media (pH<2.3) has been investigated potentiometrically and spectrophotometrically. In this condition the 1:1 complex has the formula VO2Y, where Y¯ represent the fully dissociated aminocarboxylate anion. The stability constant of VO2Y was determined as log KVO2Y=11.32±0.35 at 25±0.1 °C and I=1 mol per liter of sodium perchlorate. The protonation constant of alanine was also determined poteniumetrically under above condition.