IRON OXO AGGREGATION - FE3 TO FE6 - SYNTHESIS, STRUCTURE, AND MAGNETIC-PROPERTIES OF THE HEXANUCLEAR DICATION [FE(MU-4-O)2(MU-2-OME)8(OME)4(TREN)2]2+, A SOLUBLE, CRYSTALLINE MODEL OF IRON OXO HYDROXO NANOPARTICLES, THE CORE OF FERRITIN AND RUST FORMATION

The hydrolytic aggregation of iron(III) oxyhydroxides is modeled by the solvolysis of [Fe3(O)2(OH)(tren)3]4+ in methanol to afford a hexanuclear aggregate with mu4-O2- and bridging and terminal MeO- ligands. The resulting layered structure is a recognizable fragment of the polyoxo decametalate [M10O28]n- and is considerably more compact than carboxylate-based structures. Magnetic susceptibility reveals an intermediate-spin ground state, which probably results from spin alignment between antiferromagnetically coupled subunits.