A rare ferromagnetic μ1,1,2-oxalato-bridged Cu(II) complex

The self-assembly of a newly synthesized 1-(2-carboxyethyl)-4,4′-bipyridinium chloride (HCBpyCl) and (NH4)2[Cu(C2O4)2] affords a novel one-dimensional oxalato-bridged Cu(II) complex (H2CBpy)[Cu(C2O4)2] · 2 H2O. This is the first single oxygen-bridged metal coordination polymer constructed by oxalate ligand in relatively scarce μ1,1,2-coordination mode. Magnetic susceptibility measurements reveal a weak ferromagnetic interaction between the adjacent Cu(II) ions, which has not been observed in μ1,1,2-oxalato-bridged Cu(II) complexes.