The Reduction of Acetamidopentaamminecobalt(III) by Chromium(II)
Robert J. Balahura, Lynda Hutley · Canadian Journal of Chemistry · 1973
The reduction of nitrogen bonded acetamidopentaamminecobalt(III) by chromium(II) has been studied. The acetamido complex is a reasonably strong acid attributed to the equilibrium[Formula: see text]which has a pKa of 2.16 ± 0.08 at 25.0° and μ = 0.01 M. The reduction process has the rate law[Formula: see text]For reduction of the conjugate base k = kNHKa and kNH = 5.23 × 10−2 M−1 s−1 at 25.1°, with ΔH = 14.5 ± 2 kcal mol−1 and ΔS = 16 ± 6 e.u. respectively. The rate law is indicative of an inner-sphere process. The orientation of the ligand is thought to be important for the reduction of the acetamido and the related carboxylato complexes, and this is discussed.