Fe-Gd Ferromagnetic Cyclic Coordination Cluster [FeGd(teaH)(N)(HO)] with Magnetic Anisotropy─Theory and Experiment.

The synthesis, structural, and magnetic characterization of [FeLn(teaH)(N)(HO)] (Ln = Gd and Y) and the previously reported isostructural Dy analogue are discussed. The commonly held belief that both Fe and Gd can be regarded as isotropic ions is shown to be an oversimplification. This conclusion is derived from the magnetic data for the Y analogue in terms of the zero-field splitting seen for Fe and from the fact that the magnetic data for the new Gd analogue can only be fit employing an additional anisotropy term for the Gd ions.