The crystal structures of two dinuclear iron(III) compounds with a bent μ-oxo bridge, [Fe2O(CH3CO2)(tpa)2][ClO 4]3· 2H2O and [Fe2O(CH3CO2)(mep)2][ClO 4]3, were determined, where tpa and mep represent tris(2-pyridylmethyl)-amine and N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)ethane-1,2-diamine, respectively. Their structural features which include a (μ-oxo)(μ-acetato)diiron(III) core are very similar. In spite of this, these two complexes exhibit very different reactivity towards hydrogen peroxide in solution; the tpa complex showed high catalase-like activity, whereas that of the mep complex was negligible. In the oxygenation of cyclohexane the mep complex-H2O2 system exhibited high activity giving cyclohexanol and cyclohexanone, but formation of oxygenated products was negligible with the tpa complex-H2O2. The absorption spectrum of the tpa complex shows no change in the presence of H2O2; however a drastic change was observed in the spectrum of the mep complex on addition of H2O2. Based on the structural and spectroscopic data, the structures of the active species for catalase- and oxygenase-like functions and the origin of the differences in reactivity observed for these two compounds are discussed.
|Number of pages||5|
|Journal||Journal of the Chemical Society - Dalton Transactions|
|Publication status||Published - 1997 Oct 7|
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