Structural and magnetic properties of two copper(II) complexes based on dinuclear copper(II) metallacyclophane

Two new oxamato-bridged copper(II) complexes of formula Na-10[{Cu-2(mpba)(2)}(2)(mu(1,1)-N-3)(2)]center dot 18H(2)O (1) and [(Cu-2(mpba)(2))-Cu-2(H2O)(8)]-6H(2)O (2) [mpba = 1,3-phenylenebis(oxamatoN,N')] have been synthesized and characterized. X-ray crystallographic studies of complex 1 reveal a metallamacrocycle structure in which two dinuclear copper(II) metallacyclophane anions are linked by two single symmetric azido ligands in an end-on mode at axial-axial positions. These metallamacrocycle units are self-assembled through sodium cations and water molecules, affording an intricate 3D network. Complex 2 consists of 2D brick-wall-like layers assembled from dinuclear metallacyclophane [Cu-2(mpba)(2)](4-) anions and copper(II) cations. Magnetic susceptibility measurements of complex 1 in the temperature range 2-300 K show dominating ferromagnetic coupling mediated by the m-phenylenediamide bridge and weak antiferromagnetic interaction transmitted by the azido ligand. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).