Syntheses, crystal structures and magnetic properties of tungstato- and molybdo-bridged dinuclear copper(II) complexes

Two new dinuclear copper(II) complexes, [Cu2(bpca)2(WO4) (H2O)2] · H2O (1) and [Cu2(bpca)2(MoO4) (H2O)2] · H2O (2) [bpca = bis(2-pyridylcarbonyl)amide anion], have been synthesized and their magnetic behavior investigated as a function of temperature. The structures of 1 and 2 have been determined by single-crystal X-ray diffraction. Complexes 1 and 2 are both 3D supramolecules with intermolecular hydrogen-bonding and π–π stacking interactions. The magnetic susceptibilities measured over the range 2–300 K show ferromagnetic interaction between the two copper(II) ions in 1, while there is antiferromagnetic interaction between the two copper(II) ions in 2. Based on the Hamiltonian written as best fitting for the experimental data leads to J = 0.557 cm−1 (1) and −77.2 cm−1 (2).