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

Reaction of the new polydentate ligand 2,6-bis{3-[N,N-di(2-pyridylmethyl)am ino]propoxy}benzoic acid (LH) with Fe(ClO4)(3) followed by addition of chlo roacetic acid leads to the formation of the tetranuclear complex [{Fe2OL(Cl CH2- CO2)(2)}(2)](ClO4)(4), the crystal structure of which reveals that it consists of two Fe-2(II)(mu-O)(mu-RCO2)(2) cores that are linked via the tw o L ligands in a helical structure, with the carboxylate moieties of the tw o ligands forming a hydrogen-bonded pair at the center of the helix.