Oxidations of 4‐ and 3‐Aminopyridinepentaammineruthenium(ii) Complexes by Ethylenediaminetetraacetatocobaltate(III)

Redox reactions of Co(edta) − with Ru(NH 3 ) 5 L 2+ (L = 3‐ and 4‐aminopyridine (AmPy)) were found to follow an outer‐sphere electron transfer mechanism. The specific rate constants are (3.26 ± 0.03) × 10 2 and (3.07 ± 0.04) × 10 3 M −1 S −1 , for L = 3‐ and 4‐AmPy, respectively, at μ, = 0.10 M LiClO 4 , pH = 8.0 (tris) and T = 25 °C. The rate constants of oxidations for a series of Ru(NH 3 ) 5 L 2+ complexes are higher than those of the corresponding Fe(CN) 5 L 3‐ complexes by factors of 4 to 15 even after corrections for differences in reduction potentials and in charges of the complexes. Nonadiabaticity in the reactions of Fe(CN) 5 L3 complexes may account for the difference in the relative reactivities.