Ionic Strength Dependence of Formation Constants, Complexation of Molybdenum(VI) with Glutamic Acid

Abstract

The complexation of molybdenum(VI) with glutamic acid was investigated in aqueous solution ranging in pH from 4 to 9, using polarimetric and spectrophotometric techniques. The composition of the complex was determined by the continuous variations method. It was shown that molybdenum(VI) forms a mononuclear 1:1 complex with glutamic acid of the type MoO 3 L - 2 at pH 5.8. The protonation constants of glutamic acid (using the potentiometric technique) and the stability constant of the complex (using the spectrophotometric technique) were determined at 25 °C and at ionic strengths ranging from (0.1 to 1.0) mol dm - 3 sodium perchlorate. The dependence of the protonation of glutamic acid and the stability constants of the complex on ionic strength is described by a Debye−Huckel-type equation.