Synthesis, Structure, Magnetic and Electrochemical Properties of an Oxydiacetate Iron(II) Complex

Compound [(Fe(oda)(H2O)(2)} . H2O](n) (1) [oda = O(CH2COO)(2)(2-)] has been obtained by reaction of FeCl2 . 4H(2)O with a 1:1 mixture of O(CH2COOH)(2) and Na2CO3 in water. The structure is polymeric with concatenated {Fe(oda)(H2O)(2)} units extended in one direction. Each iron centre is six-coordinated by the tridentate planar oda ligand, two mutually trans water molecules and one oda oxygen atom from an adjacent {Fe(oda)(H2O)(2)} unit. Complex 1 is isomorphous with cobalt and zinc analogues. Magnetic susceptibility measurements down to 2 K showed high-spin non-correlated Fe(II) ions with a typical Curie-Weiss behaviour. Differential-pulse voltammetry establishes a value of 0.488 V versus NHE for the Fe(III)/Fe(II) redox potential of this iron complex in 0.25 mol dm(-3) NaNO3.