Reaction mechanisms for the radiation-induced oxidation and reduction of (dinitrogen)decaamminediruthenium(II)

The mechanism for the oxidation and reduction of [Ru(NH3)5]2N24+ by the OH radical and the hydrated electron respectively were determined by use of pulse and 60Co steady-state radiolysis. The binuclear ruthenium complex reacts with the OH radical to form an adduct [(NH3)5Ru/sup II/N2Ru/sup II/(NH3)5(OH)]4+ at a rate k4 = (2.4 +- 0.3) x 1010 M-1 s-1 which subsequently changes by a first-order process to [Ru(NH3)5]2N25+ at a rate k5 = (1.4 +- 0.4) x 104 s-1. The latter species disappears, also by a first-order reaction, k6 = 0.16 +- 0.02 s-1, to yield two permanent products, [Ru/sup II/(NH3)5N2]2+ and [Ru/sup III/(NH3)5OH]2+. The hydrated electron reduces [Ru(NH3)5]2N24+ to [Ru(NH3)5]2N23+ at a rate of k11 = (2.1 +- 0.1) x 1010 M-1 s-1, which subsequently decays by a first-order process at a rate k12 = (8.0 +- 0.4) x 104 s-1 to yield [Ru/sup II/(NH3)5N2]2+ and a number of decomposition products