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 and magnetic properties of a zig-zag formato-bridged chain complex with the formula [Cu(dpyam)(μ-O2CH)(OH2)]n(NO3)n (1) (in which dpyam = di-2-pyridylamine) 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 (Cu–N distances 1.987(3) and 2.010(3) Å) and two oxygen atoms of two different formato ligands (Cu–O distances 1.974(2) and 1.975(2) Å). 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.