Synthesis and characterization of copper(II) azide complexes containing polyamines as co-ligands

Two new copper(II) azide complexes Cu-2(pn)(2)(N-3)(4) (1) and Cu-3(dien)(2)(N-3)(6) (2) (pn = 1,3-diaminopropane and then = diethylenetriamine) have been synthesized and characterized by single crystal X-ray diffraction. In complex I each copper(II) atom is coordinated to six nitrogen atoms from four azide anions and one 1,3-diaminopropane molecule in a distorted octahedral geometry. Successive pairs of copper(II) atoms are linked by two end-on azide bridges to form a polymeric chain. In centrosymmetric complex 2 the central copper(II) is coordinated by two monodentate azide anions and linked to two terminal copper atoms by double end-on azide bridges to give a linear trinuclear unit. The coordination geometry around each of the terminal copper atoms is square pyramidal, being surrounded by two nitrogen atoms of the bridging azide anions and three nitrogen atoms of the diethylenetriamine ligand. Magnetic susceptibility measurement of complex 2 in the range 2-300 K showed weak antiferromagnetic exchange between the copper(II) ions (J = -2.09(8) cm(-1)) through the double end-on azide bridges. (C) 2004 Elsevier Ltd. All rights reserved.