Crystal structure and magnetic behaviour of a two-dimensional complex [Cu(dmen)]2[Fe(CN)6] (dmen = 2-dimethylaminoethylamine) with an exceptional cyano-bridging

The cyanide bridged bimetallic assembly [Cu(dmen)]2[Fe(CN)6] (dmen = 2-dimethylaminoethylamine) has been prepared and characterized by elemental analyses, infrared and electronic spectroscopy. The crystal structure of the compound consists of a two-dimensional polymeric sheet with two different rings, one a four membered square ring and another a twelve membered hexagonal ring. Each iron(II) ion has two free, two nearly linear bridging and two end-on bridging cyanide groups. In the crystal all the copper(II) ions have a distorted square based pyramidal geometry. From magnetic susceptibility measurements, the complex was found to exhibit a weak ferromagnetic interaction between the nearest copper atoms.