U. Nickel et al., MECHANISM AND KINETICS OF THE PHOTOCATALYZED OXIDATION OF P-PHENYLENEDIAMINES BY PEROXYDISULFATE IN THE PRESENCE OF TRI-2,2'-BIPYRIDYLYLRUTHENIUM(II), Journal of physical chemistry, 98(11), 1994, pp. 2883-2888
The autocatalytic oxidation of p-phenylenediamines with peroxydisulfat
e can be strongly enhanced by irradiation in the presence of tri-2,2'-
bipyridylylruthenium(II). Ru(bpy)3(2+) acts as photosensitizer and pho
tocatalyst. First, Ru(bpy)33+ is formed by quenching excited Ru(bpy)3
(2+) with S2O8(2-). Then the ruthenium(III) complex oxidizes p-phenyle
nediamine. The resulting Ru(bpy)3(2+) can start the cycle again. The p
hotocatalytic oxidation of N,N-diethyl-p-phenylenediamine as well as t
he dark reactions were studied with stopped-flow techniques. The mecha
nism of this complex reaction is discussed in detail.