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

Abstract

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 (μ-1,1, μ-1,3 and μ-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.