Preparation and characterization of three types of dinuclear iron(III) complexes with H2salbn, N,N′-disalicylidene-1,4-diaminobutane

By the reaction of the tetradentate Schiff base ligand H2salbn, N,N′-disalicylidene-1,4-diaminobutane with FeIIICl3·6H2O in the presence of Et3N in MeOH a dinuclear iron(III) complex, [FeIII(salbn)(μ-OMe)]2 (1), has been obtained, whereas in EtOH, dinuclear complexes, [FeIII(μ-salbn)]2(μ-O) (2) and [FeIII(salbn)]2(μ-salbn) (3), are obtained. The structure of the complex 1 consists of two Fe(III) centers with one tetradentate salbn ligand (N2O2) which are bridged by two methoxo groups to yield a planar Fe2O2 core. On the other hand, in the complex 2, each of the two Fe(III) ions has a five-coordinate structure in which both salbn ligands act as a bridging didentate ligand and one oxygen atom bridges two Fe(III) ions to form a μ-oxo structure. The structure of the complex 3, which was obtained by accompanying with complex 2, consists of two six-coordinate Fe(III) centers in which each Fe(III) ion is coordinated by a tetradentate salbn ligand (N2O2) and one bridging salbn ligand (NO).