Syntheses, crystal structures, and magnetic properties of a series of Fe2Ln complexes

The syntheses, crystal structures, and magnetic properties of four heterometallic Schiff base trinuclear [Fe(2)Ln] complexes are reported. Single-X-ray diffraction analysis reveals that the four complexes contain a blade, propeller-like configuration. Magnetic analysis of Gd-III complex shows that the magnetic interaction between Gd-III and Fe-III ions is weak ferromagnetic. A family of phenoxo-bridged heterometallic Schiff base trinuclear complexes, [Fe(2)LnL(2)(C3H7COO)(H2O)]center dot CH3OH center dot CH3CN center dot H2O (Ln = Sm, 1; Gd, 2; Tb, 3; Dy, 4) is reported. Those complexes were afforded by one-pot reaction of a polydentate Schiff base ligand 2-hydroxy-3-methoxy-phenylsalicylaldimine (H2L) with Fe(NO3)(3)center dot 9H(2)O, Ln(NO3)(3)center dot 6H(2)O and sodium butyrate (C3H7COONa) in a mixture of methanol and acetonitrile in the presence of triethylamine as a base. Single-crystal X-ray diffraction analysis reveals that the structures of the four complexes are isomorphic. In each complex, two anionic [FeL2](-) units coordinate to the central lanthanide ion as a tetradentate ligand using its four phenoxo oxygens, forming a two-blade propeller-like molecular shape. Magnetic properties of 1-4 were investigated using variable temperature magnetic susceptibility, and weak ferromagnetic exchange between the Fe-III and Ln(III) ions has been established for the Gd derivative. The Tb and Dy complexes show no evidence of slow relaxation behavior above 2.0 K.