Synthesis, crystal structure and catalytic activity for H2O2 disproportionation of the manganese(II) coordination polymer {[Mn(O2C(CF2)(8)CO2)(phen)(2)]H2O}(n) (phen=1,10-phenanthroline)

Abstract

The title polymeric complex {[Mn(O2C(CF2)(8)CO2)(phen)(2)]H2O), was synthesized through the reaction of 1,10-phenanthroline, perfluorosebacic acid and MnCO3 center dot H2O. The molecular structure was characterized by X-ray diffraction, elemental analysis, thermal gravimetry, IR and UV-Vis spectroscopy and its catalytic activity has been studied. X-ray structure analysis shows that each Mn(II) ion is octahedrally coordinated by two bidentate phenanthroline ligands and the carboxylate oxygen atoms from two symmetry related per-fluorosebacate ligands, which are coordinated in cisoid positions. The structure consists of polymeric chains, with the perfluorosebacato ligand bridging the Mn(II) ions in a monodentate fashion. Crystallographic characterization shows a supramolecular structure involving hydrogen bonds, pi-pi and pi-ring interactions. The catalytic results indicated that the complex has reasonably good activity towards the disproportionation. of hydrogen peroxide into water and dioxygen in methanol and it does not exhibit saturation kinetics with the substrate. The initial reaction rates and their temperature and base dependencies were investigated by monitoring the dioxygen evolution. Kinetic studies revealed a first-order dependence on the catalyst concentration. Activation parameters have been calculated at 301 K. (c) 2008 Elsevier Ltd. All rights reserved.