Mono-complex formation kinetics of 2-acetylcyclohexanonatochromium(III) in aqueous solution

The kinetics and mechanism of the reaction of complexation of chromium(III) with 2-acetyl-cyclohexanone has been investigated spectrophotometrically in aqueous solution at 50°C and ionic strength 0.5 mol dm^?3 NaClO₄. The equilibrium constants of the complex have been determined. The mechanism proposed to account for the kinetic data involves a double reversible pathway where both Cr³⁺ and Cr(OH)²⁺ react with the enol tautomer of the ligand with rate constants of 9.6 × 10^?3 dm³ mol^?1 s^?1, and 3.69 × 10^?2 dm³ mol^?1 s^?1, respectively. Some discussions are made on the basis of Eigen-Wilkins theory considering the effect of solvent exchange on the complex formation.