The Magnetic, Electronic, and Mössbauer Spectral Properties of Several Trinuclear Iron(III) Carboxylate Complexes

Each of the formate, acetate, monochloroacetate, trichloroacetate, phenylacetate, and benzoate complexes iron (III), prepared and characterized for study is triangular trinuclear in structure and contains six bridging carboxylate ligands and a central bridging oxygen. Magnetic susceptibility measurements from room temperature to 20 K indicate non-equivalent, antiferromagnetic coupling of the three high-spin iron (III) ions. The Mössbauer spectrum of each of the complexes exhibits quadrupole line asymmetry, which is attributed to the Gol'danskii-Karyagin effect. The i.r. spectrum and electronic spectrum of each complex are reported and discussed in terms of the observed antiferromagnetic coupling.