Cobalt, tris conformation reactions

Cobalt, tris(l,2-ethanediamine)-conformation, 1,25,197 polarography, 1,481 racemization, 1, 466 solid state, 1,466,467 reactions, 1, 27 redox potential, 1, 514 structure, 1, 67... 

Sutin s kinetic studies on the oxidation of horse-heart ferrocytochrome c by tris-(phen)cobalt(iii) have recently been extended to acid pH. The reaction is first-order with respect to each reactant but the dependence of the rate on [H+] is not simple. Measurements in chloride medium (7=0.13 mol 1 ) over the pH range 1—7 revealed a rate maximum at pH 2.9 (A =6.7x 10 1 mol" s at 25 °C). By contrast, the rate constants at pH 1.0 and 5.8 are 3.2 x 10 and 2.1 x 10 1 mol" S", respectively. Below pH 1.7, biphasic kinetics are observed, the slower reaction having a rate constant of ca. 2 s" (independent of oxidant concentration). The slow process is ascribed to a conformational change in the ferricytochrome c which is produced in... 

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