Kinetic and Mechanistic Studies on the Reaction of DL-Methionine with [(H2O)‎(tap)‎2RuORu(tap)‎2(H2O)‎]2+ in Aqueous Medium at Physiological pH

Abstract EN

The reaction has been studied spectrophotometrically; the reaction shows two steps, both of which are dependent on ligand concentration and show a limiting nature.

An associative interchange mechanism is proposed.

Kinetic and activation parameters (k1∼10−3s−1 and k2∼10−5s−1) and (ΔH1 ≠=13.8±1.3 kJ mol−1, ΔS1 ≠=−250±4 JK−1 mol−1, ΔH2 ≠=55.53±1.5 kJ mol−1, and ΔS2 ≠=−143±5 JK−1 mol−1) have been calculated.

From the temperature dependence of the outer sphere association equilibrium constant, thermodynamic parameters (ΔH1 ∘=16.6±2.3 kJ mol−1 and ΔS1 ∘=95±7 JK−1 mol−1; ΔH2 ∘=29.4±3.2 kJ mol−1 and ΔS2 ∘=128±10 JK−1 mol−1) have also been calculated.