Novel copper-azido magnetic molecular tapes: syntheses, structures, and magnetic properties

The reactions of copper(ii) ions with azido ligands in the presence of different chelating amine ligands gave three one dimensional copper-azido molecular tapes, [Cu2(N-Pren)(N3)4]n (1), [Cu2(N-Buen)(N3)4]n (2) and [Cu3(tren)(N3)6]n (3) [N-Pren = N-propylethylenediamine; N-Buen = N-butylethylenediamine; tren = tris(2-aminoethyl)amine]. Complexes 1 and 2 are composed of 1D coordination chains based on the step-like tetranuclear copper(ii) clusters which feature three types of azido bridging modes ([small mu ]-1,1, [small mu ]-1,3 and [small mu ]-1,1,1). Complex 3 is a novel 1D molecular tape featuring zigzag hexanuclear copper-azido subunits with only end-on azido bridges. Magnetic studies show ferromagnetic coupling in 1 and 2, and antiferromagnetic coupling in 3. The magnetic data for 1 and 2 were fitted with a tetranuclear copper theoretical model.