Synthesis, crystal structure and magnetic properties of a polynuclear Cu(II) complex: catena-poly[aqua(di-2-pyridylamine)copper(II)(μ-formato-O,O′)nitrate]

The synthesis, X-ray structure, spectroscopic properties, magnetic study and EPR of a chain-type formato-bridged Cu(II) compound, [Cu(dpyam)(μ-O2CH)(H2O)]n(NO3)n (1) is described. The geometry of the copper(II) ion is distorted square pyramidal with a basal plane consisting of two nitrogen atoms of the dpyam ligand and two oxygen atoms of two different formato ligands. A coordinated water molecule occupies the axial position at a distance of 2.222(3) Å. The copper atoms are bridged unsymmetrically by a formato anion in a syn-anti arrangement, resulting in a polymeric zig-zag chain structure. The magnetic susceptibility measurements (5-280 K) agree with a very weak ferromagnetic chain interaction between the Cu centres with a J value of 0.75 cm−1.