SUBSTITUTION KINETICS OF S-DIAQUA-BIS-(2-(M-TOLYLAZO)PYRIDINE)RUTHENIUM(II) ION WITH THIOUREA

The kinetics and mechanism of substitution of s-diaqua-bis-{2-(m-tolyl azo)pyridine}ruthenium(II) with thiourea have been investigated spectr ophotometrically as a function of [substrate complex], ionic strength, pH, [thiourea], temperature and medium dielectric constant. The react ion rate is independent of ionic strength but dependent on pH in the p H range 4-6. The activation parameters measured for this system have b een compared with those of similar systems. The reaction rates are ins ensitive to the nature of incoming ligands and a dissociative mechanis m has ben proposed. The decrease of reaction rate with decrease in med ium dielectric constant is also a logical consequence of such mechanis m.