A New Type of Trinuelear Oxoiron(III) Cluster

摘要

The seat eh for polynuclear oxo- and. or hydroxo-bridged iron complexes has been motivated by their implications in natural systems. The simplest diiron(III) centers have been structurally identified in the actrve site of hemerythrin, methane monooxy-genase, and ribonucleotide reductase, in which they are involved in dioxygen transport or activation. Recent studies have revealed the pote.ifial of synthetic model complexes containing, a Fe-O-Fe unit as catalysts for the oxidation of alkalies by peroxides. Moreover, such centers are early intermediates in the formation of large hydroxo(oxo)iron aggregates in the interior of ferritin, the multisubunit iron-storage protein Information on the transition of binuclear oxo-bridged iron(III) complexes intoclusters of higher nuclearity is sparse, and mechanisms of the first steps of the formation of the ferritin iron core are still ill-defined. Our recent investigations of the chemical reactivity of dibridged mu-acetato(mu-oxo)diiron(III) model complexes showed that complex 1 could, in the presence of an organic base, generate complex 2. which has an unprecedented triiron eore. Herein wc report the preparation, the X-ray structure, and the spectroscopie and magnetic properties of this new type of car-boxylato(oxo)iron cluster.