A novel 2D oxalate- and dissymmetrical oxamidato-bridged heterometallic CuII–GdIII complex: Synthesis, crystal structure and magnetic properties

A novel 2D framework, {[Cu2(aeoe)2Gd2(C2O4)(H2O)6]·7H2O}n (1) (H4aeoe = N′-(2-aminoterephthalic acid)-N″-(ethylenediamine) oxamidato), has been synthesized and characterized by elemental analysis, IR spectrum, thermogravimetric analysis (TGA), single-crystal X-ray diffraction and magnetic properties. Single-crystal structural analysis shows that complex 1 displays a novel 2D layered structure. The asymmetry unit of complex 1 contains a heterotetranuclear CuII2GdIII2 building block. The Cu(II) ions are in a distorted square pyramidal CuN3O2 surrounding. The Gd(III) ions are eight-coordinated and surrounded by two oxygen atoms from oxamide group, one oxygen atom from carboxylate, two oxygen atoms from oxalate and three oxygen atoms from coordination water molecules. The framework formed using dissymmetrical oxamide and oxalate anions as mixed ligands is the first examples of 3d–4f complexes involving dissymmetrical oxamide. Its magnetic properties have also been investigated, and show weak ferromagnetic coupling between the Cu(II)–Gd(III) ions.