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

Abstract

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 (HL¹) and 4-(2′-methoxycarbonyl-2′-oxoethylidene)-2,2,5,5-tetramethyl-3-imidazoline-1-oxyl (HL²) 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-CuL² ₂ at ∼ 5 K. Easy magnetization axes were determined for both compounds. At the same time, the complex β-CuL² ₂, possessing a molecular structure, does not show noticeable anisotropy in the region 2–300 K. For the layered complex CoL¹ ₂, the magnetic transition temperature, if any, is lower than 2 K. In the whole range 2–300 K, the single crystals of CoL¹ ₂ show a rather high anisotropy of magnetic susceptibility.

Key Words:

• magnetic susceptibility
• single crystal
• ferromagnetic ordering