Synthesis, characterization and catalytic activity under homogeneous conditions of ethylene glycol substituted porphyrin manganese(III) complexes

The catalytic efficiency and selectivity of a series of manganese(III) complexes of meso-tetrakis(pentafluorophenyl)porphyrin H-2(TPFPP) derivatives bearing one to four ethylene glycol moieties are compared in the oxidation of cis-cyclooctene and cyclohexane in the presence of H2O2 at ambient temperature. The results show that the catalysts' performance depends on the number of ethylene glycol moieties present and on the cocatalyst used; for both substrates, the most efficient catalyst in the presence of H2O2 is the Mn(III) complex bearing three ethylene glycol moieties (MnP3). Moreover, in the oxidation of cyclohexane in the presence of iodosylbenzene (PhIO) as oxidant, all the substituted Mn(III) complexes are more efficient than the parent non-substituted Mn(III) porphyrin complex. In addition, during the preparation of this series of derivatives, the tetrasubstituted free-base porphyrin (P4) was further isolated and studied in the solid state, by using single-crystal X-ray diffraction studies. (C) 2016 Elsevier B.V. All rights reserved.