Kinetics and mechanism of complexation of Co(II) with 4-aminobenzoic acid
Kinetic and mechanism of complexation of Co(II) with 4-aminobenzoic acid has been carried out under first order conditions as a function of pH and temperature. A reaction scheme consistent with the kinetic data has been proposed. The ionic strength was maintained at 0.1 M KNO3. Kinetic results indicate that the ligand is not involved in the rate determining step which is, in fact, associated with the release of a water molecule from the shell of the metal ions prior to complexation with the ligand. The overall rate constant has been resolved into stepwise rate constants. The suggested mechanism is confirmed by the calculation of activation parameters and water exchange rate constant. Deprotonated form of 4-aminobenzoic acid is more reactive and the protonated form interacts only to a small extent.