OXIDATIONS OF 4-AMINOPYRIDINEPENTAAMMINERUTHENIUM(II) AND 3-AMINOPYRIDINEPENTAAMMINERUTHENIUM(II) COMPLEXES BY ETHYLENEDIAMINETETRAACETATOCOBALTATE(III)

Redox reactions of Co(edta)(-) with Ru(NH3)(5)L(2+) (L = 3- and 4-amin opyridine (AmPy)) were found to follow an outer-sphere electron transf er mechanism. The specific rate constants are (3.26 +/- 0.03) x 10(2) and (3.07 +/- 0.04) x 10(3) M(-1)S(-1), for L = 3- and 4-AmPy, respect ively, at mu = 0.10 M LiClO4, pH = 8.0 (tris) and T = 25 degrees C. Th e rate constants of oxidations for a series of Ru(NH3)(5)L(2+) complex es are higher than those of tile corresponding Fe(CN)(5)L(3-) complexe s by factors of 4 to 15 even after corrections for differences in redu ction potentials and in charges of the complexes. Nonadiabaticity in t he reactions of Fe(CN)(5)L(3-) complexes may account for the differenc e in the relative reactivities.