Synthesis, Structure, and Catalytic Activity of New μ‐Oxo‐Bridged Diiron(III) Complexes

Abstract

AbstractThe preparation and characterisation of two dinuclear iron(III) complexes with tripodal ligands 1,3‐bis(2′‐pyridylimino)isoindoline (indH) are presented. The μ‐oxo‐bridged diiron(III) complex [{FeCl(ind)}2O] (2) has been prepared by reacting FeCl3·6H2O with indH in methanol solution. Compound [{Fe(ind)(OAc)}2O] (3) was obtained from the reaction of 2 with CH3CO2Ag in THF. Both compounds were characterised by elemental analysis and UV/vis, IR, and Mössbauer spectroscopy. The X‐ray structure analysis of [Fe2O(ind)2Cl2]·THF (2·THF) revealed a distorted trigonal bipyramidal (τ = 0.88) coordination geometry around the iron(III) ion. More importantly, 2 is a good functional model for the activation of small molecules as its 5‐coordinate iron ions can easily coordinate such molecules. This is confirmed by the high catalase‐like activity of 2, transforming 87% of the excess of H2O2 into O2 in 1 min. The complexes exhibited monooxygenase‐like activity using H2O2 as the oxidant and oxidise alkanes to alcohols and ketones in acetonitrile in moderate yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)