The doubly oxo-bridged dinuclear Fe(III) complex, [Fe2(hmp)2Cl4], as a reaction product of the [Mn4(hmp)6(NO3)2(H2O)2]2+ cluster with [FeCl4]−

The bis(μ-alkoxo)-bridged dinuclear iron(III) complex, [Fe2(hmp)2Cl4] (I), [hmp = 2-hydroxymethylpyridine] was synthesized by reaction of the [Mn4(hmp)6(NO3)2(H2O)2](ClO4)2 with (Et4N)[FeCl4] under conditions of slow diffusion of starting reagents into solvent and characterized by single crystal X-ray diffraction and variable-temperature magnetic susceptibility measurements. The iron centers have a mixed-ligand five-fold coordination (O2NCl2) with a distorted trigonal bipyramidal geometry. Two Fe(III) ions are bridged by the oxygen atoms from two hmp ligands, with Fe ⋅ ⋅ ⋅ Fe distance of 3.158(1) Å and Fe-O-Fe bridge angle 107.37(7)°. Magnetic studies in the temperature range 300–4.2 K indicated a moderately strong intramolecular antiferromagnetic coupling between the high-spin Fe(III) ions with J = − 38.5 cm− 1.