Magnetic properties of an oxo-bridged dinuclear iron(III) complex resulting from the oxidation of mononuclear iron metallacycles with a flexible ethylenediphenylenebis(oxamate) ligand

Transition metal ions such as copper(II), nickel(II), cobalt(II), and manganese(II) are widely used in the for-mation of mono-or oligonuclear metallacyclic complexes with the flexible N,N'-2,2 & PRIME;-ethylenediphenylenebis (oxamate) ligand (H4edpba); however similar supramolecular complexes with iron(II) and iron(III) are rarely obtained. In this work, we synthesized for the first time a new air-stable oxo-bridged diiron(III) complex of formula {[Fe(H2edpba)(dmso)]2(& mu;-O)}& BULL;dmso & BULL;H2O (2) from dioxygen oxidation of the putative mononuclear iron (II) complex precursor of formula [Fe(H2edpba)(H2O)2]Cl (1) in dimethylsulfoxide (dmso). Compound 2 crys-tallizes in the monoclinic system and contains one oxo group bridging two cationic mononuclear metallacyclic moieties, [Fe(H2edpba)(dmso)]+. The iron(III) ions are also coordinated to four oxygen atoms from the dianionic H2edpba2-ligands in a tetradentate fashion, while an oxygen atom from the coordinated dmso molecules. Mo & BULL;ssbauer spectroscopy confirms the presence of high-spin (HS) Fe3+ ions (2). The magnetic properties of 2 reveal a strong antiferromagnetic interaction between the two HS Fe3+ ions (J =-226.46 cm-1), in agreement with the DFT calculations (J =-207.99 cm-1).

Automated summary

In this study, a new air-stable oxo-bridged diiron(III) complex was synthesized for the first time, and its magnetic properties were confirmed through experimentation.