Abstract
The oxidation of [Co-II(nta)(M)(H2O)(2)](3-) by periodate has been studied kinetically in aqueous solution over 20.0-40.0 degrees C and a variety of pH ranges. The rate of oxidation of [Co-II(nta)(M)(H2O)(2)](3-) by periodate, obeys the following equation:
d[Co-III](T)/dt = (k(2)K(3) + k(1), K-2 K-1/[H+]) [IO4-][Co-II](T)(1 + (K-1/[H+]) + (K-3+ K1K2/[H+])[IO4-])
Initial cobalt(III) products were formed and slowly converted to final products, fitting an inner-sphere mechanism. Thermodynamic activation parameters have been calculated. A common mechanism for the oxidation of a ternary nitrilotriacetatocobalt(II) complexes by periodate is proposed and supported by an excellent isokinetic relationship between Delta H* and Delta S* values for these reactions.