AN ALTERNATING COPPER(II) CHAIN WITH BRIDGING AZIDE AND OXAMIDATE LIGANDS - CRYSTAL-STRUCTURE AND MAGNETIC-PROPERTIES OF [CU-2(DMAEOXD)(N-3)(2)(H2O)(2)] AND [(CU-2(DMAEOXD)(N-3)(2))N] )DMAEOXD=N,N'-BIS[2-(DIMETHYLAMINO)-ETHYL]OXAMIDE)

Two new azide-containing complexes [Cu-dmaeoxd(N-3)(2)(H2O)(2)] 1 and [{Cu-2(dmaeoxd)(N-3)(2)}n] 2 {H(2)dmaeoxd = N,N'-bis[2-(dimethylamino) ethyl]oxamide} have been synthesized and characterized by single-cryst al X-ray diffraction methods: 1, triclinic, space group P (1) over bar , a = 8.620(3), b = 9.824(3), c = 11.216(3) Angstrom, alpha = 85.56(3) , beta = 86.90(3), gamma = 89.98(3)degrees and Z = 2; 2, monoclinic, s pace group P2(1)/n, a = 9.185(1), b = 11.477(4), c = 7.917(3) Angstrom , beta = 100.88(3)degrees and Z = 2. The structure of 1 is made up of two neutral centrosymmetric trans oxamidate-bridged copper(II) dinucle ar units with unidentate azide ligands and weakly co-ordinated water m olecules. Each copper atom has a distorted square-pyramidal geometry w ith an oxygen and two nitrogen atoms from the oxamidate group and one nitrogen atom from the azide group forming the equatorial plane and on e oxygen atom from water at the axial position. The structure of 2 con sists of neutral chains of copper (II) with an alternating azide-oxami date bridging arrangement. The oxamidate group acts as a bis(terdentat e) ligand as in 1 and the azide bridges the metal atoms in an asymmetr ical end-on fashion. Each copper atom has a distorted square-pyramidal geometry with one oxygen and two nitrogen atoms from the oxamidate li gand and one nitrogen atom from the azide group in the equatorial plan e, whereas the axial position is occupied by a nitrogen atom of anothe r azide group. The metal-metal separation through the oxamidate in eac h compound is very similar [5.202(1) in 1 and 5.232(1) in 1 and 5.286( 1) Angstrom in 2] and much larger than that through azide in 2 [3.395( 1) Angstrom]. An investigation of the magnetic properties of 1 and 2 i n the temperature range 80-300 K revealed the occurrence of strong ant iferromagnetic interactions through oxamidate in both compounds and a weaker ferromagnetic coupling through the end-on azide bridge in 2.