OXIDATIVE CONVERSIONS OF ORTHOPHENYLENEDIAMINE DURING COMPLEX-FORMATION WITH POTASSIUM HEXACHLOROOSMATE(IV)

Confirmation is provided for the previously published suggestion that the reaction of potassium hexachloroosmate(IV) with orthophenylenediam ine proceeds by stepwise inner-sphere oxidation of o-phenylenediamine to benzoquinonediimine via formation of an intermediate [Os(sbqdi)2]Cl 2 complex, where sbqdi = benzosemiquinonediimine. The compound was cha racterized by elemental analysis and IR and PMR spectroscopy, as well as electronic spectroscopy in the visible range. Inner-sphere oxidatio n of benzosemiquinonediimine to benzoquinonediimine was shown to have an intramolecular character. A sequence is suggested for the oxidation -reduction conversions in the course of the reaction.