OXIDATION OF ALKANES BY TERT-BUTYL HYDROPEROXIDE CATALYZED BY POLYNUCLEAR MANGANESE SCHIFF-BASE COMPLEXES

The polynuclear manganese(III) Schiff base complexes 1-7 containing mu -alkoxo and mu-acetato bridging and a variety of structural features w ere employed as catalysts for oxidation of cyclohexane by tert-butyl h ydroperoxide in acetonitrile solution at room temperature. Oxidation o f cyclohexane using complexes 1 to 5 gave cyclohexanol and cyclohexano ne in moderate to high yields. However, the complexes 6 and 7 possessi ng chloride ligands, were inactive as catalysts. The complexes 1 and 2 were further employed as catalysts for oxidation of other substrates viz. adamantane, toluene, ethylbenzene, cumene, cis-cyclooctene, trans -stilbene and cyclohexanol. Dual mechanistic pathways involving predom inantly a metal based oxidant proceeding in a heterolytic manner and a simultaneous free radical autoxidation are proposed for the oxyfuncti onalization of alkanes.