Abstract

Two new oxo complexes, namely hexa-μ2-acetato- acetatoaquabis(di-3-pyridylamine)di-μ3-oxo-tetrairon(III) chloride monohydrate ethanol 1.25-solvate, [Fe4(C2H 3O2)7O2(C10H 9N3)2(H2O)]C1·1.25C 2H6O·H2O, (I), containing a tetranuclear [Fe4(μ3-O)2]8+ unit, and 2-methylimidazolium hexa-μ2acetato-acetatodiaqua-μ3- oxo-triiron(III) chloride dihydrate, (C4H7N 2)[Fe3(C2H3O2) 7O(H2O)2]Cl·2H2O, (II), with a trinuclear [Fe3(μ3-O)]7+ unit, are presented. Both structures are formed by two well differentiated entities, viz. a compact isolated cluster composed of FeIII ions coordinated to O2- and CH3CO2 - anions, and an external group formed by a central Cl- ion surrounded by different solvent groups to which the anion is bound through hydrogen bonding. In the case of (I), charge balance cannot be achieved within the groups, so the structure is macroscopically ionic; in the case of (II), in contrast, each group is locally neutral owing to the internal compensation of charges. The trinuclear complex crystallizes with the metal cluster, chloride anion and 2-methylimidazolium cation bisected by a crystallographic mirror plane. © 2006 International Union of Crystallography.