Synthesis and characterization of iron(III) complexes of a new ligand containing a potentially bridging carboxylate; structural characterization of a helical tetranuclear iron complex

Abstract

Reaction of the new polydentate ligand 2,6-bis{3-[N,N-di(2-pyridylmethyl)amino]propoxy}benzoic acid (LH) with Fe(ClO₄)₃ followed by addition of chloroacetic acid leads to the formation of the tetranuclear complex [{Fe₂OL(ClCH₂- CO₂)₂}₂](ClO₄)₄, the crystal structure of which reveals that it consists of two Fe^II₂(µ-O)(µ-RCO₂)₂ cores that are linked via the two L ligands in a helical structure, with the carboxylate moieties of the two ligands forming a hydrogen-bonded pair at the center of the helix.