Crystal structure of gluconate bound iron(III) complex: synthesis, characterization and redox properties of the complex in aqueous solution

By Stewart, Christopher D.; Arman, Hadi; Benavides, Brenda; Musie, Ghezai T. From New Journal of Chemistry (2018), 42(18), 15088-15096.

A novel tetra-​iron(III) complex, K6[Fe4(ccdp)​2(μ-​O)​(μ-​OH)​(D-​GluA)​2]​(NO3)​3·10H2O (K6[1]​(NO3)​3·10H2O) with two gluconato and two N,​N’-​bis[2-​carboxobenzomethyl]​-​N,​N’-​bis[carboxomethyl]​-​1,​3-​diaminopropan-​2-​oxy (ccdp5-​) ligands has been synthesized and fully characterized using different techniques including single crystal x-​ray crystallog.  K6[1]​(NO3)​3·10H2O showed stability aq. soln., in biol. samples such as human and fetal bovine serum (HS and FBS) and cell cultures such as phosphate buffer saline and min. essential medium (PBS and MEM) using UV-​visible spectroscopy at room temp. and 37°.  The redox behavior of the complex was studied using cyclic and square wave voltammetries in aq. and DMF solns.  Furthermore, magnetic study using ESR spectroscopy and Guoy balance magnetic moment measurements indicated antiferromagnetic coupling among the metal centers of the (μ-​O)​(μ-​OH) bridged tetra-​iron(III) anion core of the complex.  Electrochem. studies of the K6[1]​(NO3)​3·10H2O in aq. and DMF solns. using cyclic and square-​wave voltammetries revealed multi-​accessible electron metal-​based redox events.