The First Tetranuclear Iron(II)‐Gadolinium(III) Carboxylate Complex [Fe2Gd2(piv)10(bpy)2]: Synthesis, Structure Elucidation and Magnetic Properties

Abstract

AbstractThe interaction of in situ generated iron(II) complex {Fe(piv)2(bpy)} and gadolinium(III) pivalate [Gd(piv)3]n in the ratio Fe : Gd=1 : 1 leads to new tetranuclear heterometallic complex [Fe2Gd2(piv)10(bpy)2] (1) of the rare {FeII2GdIII2} type (piv is pivalate anion, bpy is 2,2′‐bipyridine). According to X‐ray analysis, a tetranuclear zig‐zag {FeGdGdFe} heterometallic core is formed from two {FeGd} fragments connected by two bridging piv‐anions. The coordination environments of two iron(II) (FeO4N2) can be described as strongly distorted octahedrons, while the environment of the gadolinium(III) (GdO7) – as capped trigonal prisms. The coordination environment of each iron(II) is supported by terminal bpy ligands. The measurements of the temperature dependence of magnetic susceptibility of 1 show avery weak antiferromagnetic exchange between high‐spin Gd3+ (SGd=7/2) and Fe2+ (SFe=2) paramagnetic centers. The alternating current magnetic susceptibility measurements did not reveal any sign of magnetization slow relaxation in complex 1.