Crystal structure and magnetic properties of [Cu(ox)(py)2](py = pyridine): a ferromagnetic oxalate-bridged zigzag chain complex

Abstract

The compound [Cu(ox)(py)₂](ox = oxalate, py = pyridine) was obtained as a breakdown oxidized product of [Cu(epgly)₂](Hepgly =N-2-ethylphenylglycine), and has been characterized by means of structural and magnetic measurements. The crystals are monoclinic, space group C2/c, with a= 14.088(3), b= 11.023(2), c= 8.689(2)Å, β= 92.23(3)° and Z= 4. The structure was solved and refined to R= 0.039 and R′= 0.040. The structure consists of [Cu(py)₂]²⁺ units bridged sequentially by centrosymmetric oxalate anions to form zigzag polymeric chains parallel to the c axis, with a copper–copper distance of 5.463(1)Å. The copper ion is in distorted-octahedral environment and the equatorial co-ordination sites are occupied by N,N′ and O,O′ donors from two oxalate and two pyridine molecules at ca. 2.0 Å. Two weaker axial bonds are formed with O″ and O″′ atoms from two oxalate anions, with a O(1″)–Cu–O(1″′) angle of 162.9(1)°. From the magnetic susceptibility measurements, the complex is found to exhibit weak ferromagnetic exchange interaction between nearest-neighbour copper(II) ions.