Département de chimie moléculaire

The catalytic oxidn. of a series of alkenes by three Mn(II) complexes, MnCl2[(-)-L]2 (I), ({\{}MnCl[(-)-L]{\}}2($μ$-Cl)2) (II), and Mn(CF3SO3)2[(-)-L]2 (III), having the bidentate N-ligand (-)-pinene[5,6]bipyridine, (-)-L, and using peracetic acid as oxidant in acetonitrile was carried out. The performance of catalysts I and II is enhanced by the use of additives (NaHCO3 and imidazole) and also using a [bmim]/acetonitrile mixt. as reaction media. The latter conditions allow recyclability of the catalytic system, keeping good selectivity and conversion values in some cases. The nature of the species formed in acetonitrile after the addn. of peracetic acid was investigated through EPR and UV/Vis spectroscopy. The results point to the formation of high-valent manganese species, among which a di-$μ$-oxo-bridged Mn2(III,IV) binuclear species was unambiguously identified for complex III through a typical 16-line EPR signature. © 2014 Wiley-VCH Verlag GmbH {&} Co. KGaA, Weinheim. [on SciFinder(R)]