Synthesis, structure, magnetic properties and EPR spectroscopy of a copper(II) coordination polymer with a ditopic hydrazone ligand and acetate bridges

A new one dimensional coordination polymer of copper(II), [Cu-4(L)(2)(mu(2)-1,1-OAc)(2)(mu(2)-1,3-OAc)(4)](n) (1), has been synthesized and characterized by spectroscopic methods and single crystal X-ray analysis [HL = (E)-N'-(phenyl(pyridin-2-yl)methylene)isonicotinhydrazide, OAc = acetate anion]. The coordination polymer contains two kinds of Cu(II) dimers which are connected by two types of acetate (mu 2-1,1- and mu(2)-1,3-) bridging groups. The ditopic isonicotinhydrazone ligand coordinates to the Cu1 center through the N2O-donor set and connects to the Cu2 center by a pyridine group of the isonicotine part. The EPR and magnetic susceptibility measurements confirm the existence of two kinds of Cu(II) dimers. The intradimer isotropic exchange was estimated to be +0.80(1) cm(-1) for the ferromagnetic Cu1 center dot center dot center dot Cu1 dimeric unit and -315 (1) cm(-1) for the antiferromagnetic Cu2 center dot center dot center dot Cu2 dimeric unit.