The oxidation of some ruthenium(II) complexes by ceric ion

Abstract

The rate constants for the oxidation of some o-phenanthroline and bipyridyl complexes of ruthenium(II) by cerium(IV) in 0·5M-sulphuric acid, and that of the unsubstituted o-phenanthroline complex in 1M-nitric acid, at the same ionic strength, are reported. These results are shown to be consistent with the Marcus theory for outersphere electron-transfer reactions. The oxidation of the 3- and 5-sulphonic-substituted iron(II) tris-o-phenanthroline complexes has also been studied, and the results are interpreted to show that the mechanism is outer-sphere and that the ligand does not behave as an electron mediator.