Magnetic Properties of the Single Crystals of Layered Cu(II) and Co(II) Complexes with 3-Imidazoline Nitroxides

Single crystals of Cu(II) and Co(II) complexes with stable nitroxides 4-(2′-ethoxycarbonyl-2′-oxoethylidene)-2,2,5,5-tetramethyl-3-imidazoline-1-oxyl (HL 1 ) and 4-(2′-methoxycarbonyl-2′-oxoethylidene)-2,2,5,5-tetramethyl-3-imidazoline-1-oxyl (HL 2 ) have been investigated by the static magnetic susceptibility method. It was found that bulk ferromagnetic ordering is inherent in layered CuL 1 2 and α-CuL 2 2 at ∼ 5 K. Easy magnetization axes were determined for both compounds. At the same time, the complex β-CuL 2 2 , possessing a molecular structure, does not show noticeable anisotropy in the region 2-300 K. For the layered complex CoL 1 2 , the magnetic transition temperature, if any, is lower than 2 K. In the whole range 2-300 K, the single crystals of CoL 1 2 show a rather high anisotropy of magnetic susceptibility.