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, [Cu-2(N-Pren)(N-3)(4)](n) (1), [Cu-2(N-Buen) (N-3)(4)](n) (2) and [Cu-3(tren)(N-3)(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 (mu-1,1, mu-1,3 and 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.