Two diammonium copper azides with similar layerlike magnetic substructures made of chains of serially connected Cu-6 rings show cation-modulated magnetism

We present here the first examples of Cu-azide compounds synthesized by using protonated diamine ions as cationic templates: (dmenH(2)) [Cu-6(N-3)(14)] and (trimenH(2))[Cu-6(N-3)(14)] (dmenH(2)(2+): N,N'-dimethylethylenediaminonium; trimenH(2)(2+) : N,N,N'-trimethylethylenediammonium). Both compounds possess a similar, rarely observed anionic Cu-azide layer, which consists of [Cu-6(N-3)(14)(2-)](n) anionic chains linked by asymmetric end-to-end azido bridges. The chain, in turn, is made up of elongated Cu-6 rings, with double and single end-on azido linkages between the square-planar Cu2+ sites within the ring and double end-on azido bridges serially connecting the rings. ne molecular geometry results in ferromagnetic interactions within the Cu-azide layer in both compounds. The interlayer separations are determined by the cations, with the shortest interlayer Cu center dot center dot center dot Cu separations being 8.016 angstrom for the dmenH(2)(2+) compound and 9.106 angstrom for the trimenH(2)(2+) compound. These different interlayer separations tune the magnetic properties of the two materials. The dmenH(2)(2+) compound displays long-range antiferromagnetic ordering at lowtemperature and short-range ferromagnetic interaction at high temperature, while only short-range ferromagnetism was observed in the trimenH(2)(2+) compound at 2-300 K.