A seven-coordinate FeIII compound: [Fe{O(CH2CO2)2}(H2O)2(NO3)]. Preparation, structure and magnetic properties

The reaction of Fe(NO3)3 · 9H2O with oxydiacetic acid in water produces the seven-coordinate complex [Fe{O(CH2CO2)2}(H2O)2(NO3)] in which the FeIII is bonded to a tridentate oda and a bidentate nitrate in a pentagonal plane and two axial water molecules. Zero field splitting parameters D = 0.81 cm−1, E/D = 0.33 and weak antiferromagnetic interactions with J ≈ −0.06 cm−1 between FeIII neighbors were evaluated from susceptibility measurements. The exchange interaction is transmitted by bridges containing five diamagnetic atoms, including one hydrogen bond.