Synthesis and Characterization of Symmetrically versus Unsymmetrically Proton-Bridged Hexa-Iron Clusters

Abstract

Syntheses and magnetic and structural characterization of hexa-iron complexes of derivatized salicylaldoximes are discussed. Complexation of Fe(BF4)2·6H2O with each ligand (H2L1 and H4L2) in a methanolic-pyridine solution resulted in hexa-iron compounds (C1 and C2, respectively), which each contain two near-parallel metal triangles of [Fe3-μ3-O], linked by six fluoride bridges and stabilized by a hydrogen-bonded proton between the μ3-O groups. Within each metal triangle of C2, Fe(III) ions are connected via the amine "straps"of (H4L2-2H). Variable-temperature magnetic susceptibility and Mössbauer data of C1 and C2 indicate the presence of dominant antiferromagnetic interactions between the h..