Synthesis, structure and magnetic properties of an oxo-bridged dinuclear iron(III) complex [(TPyA)FFeIIIOFeIIIF(TPyA)](BF4)2 · 0.5MeOH (TPyA = tris(2-pyridylmethyl)amine) containing the FFeIIIOFeIIIF linkage

The reaction of [FeII(H2O)6](BF4)2 with tris(2-pyridylmethyl)amine (TPyA) and triethylamine in methanol under aerobic conditions forms [(TPyA)FFeIIIOFeIIIF(TPyA)](BF4)2 · 0.5MeOH (1), in which each Fe(III) ion is coordinated to a TPyA and an F− ion as well as an oxo ion (O2−) linking two Fe(III) ions. 1 has offset face-to-face π–π interactions between the dimers, and possesses a supramolecular network structure. The magnetic susceptibility of 1 can be fit with g = 2.0, J/kB = − 153 K (106 cm−1), and θ = − 0.3 K [H = − 2JSa · Sb]. These indicate that very strong antiferromagnetic interactions occur via the oxo bridge within the Fe(III) dimer and weak antiferromagnetic interactions between the dimers.

Graphical abstract[(TPyA)FFeIIIOFeIIIF(TPyA)](BF4)2 · 0.5MeOH (1), containing an F− ion on each Fe(III) ion has been prepared. The structure of 1 displays unsymmetrical FFeOFeF linkage, and a supramolecular network structure. There is strong antiferromagnetic interactions within the iron(III) dimer via the oxo anion.Figure optionsDownload full-size imageDownload as PowerPoint slide