Synthesis and Characterization of Binuclear (μ-Oxalato) Copper(II) Complexes with N,N′-Diethylethylenediamine or N,N,N′-Trimethylethylenediamine

Three new binuclear w -oxalato copper(II) complexes of composition [(Cu(N,N' -dieten) H₂O)₂ox](ClO₄)₂ ·H₂O (1) (N,N'-dieten = N,N'-diethylethylenediamine, H₂ox = oxalic acid), [(Cu(trimeen)H₂O)₂ox](ClO₄)₂·2H₂O (2) (trimeen = N,N,N'-trimethylethylenediamine) and [(Cu(trimeen)H₂O)₂ox](NO₃)₂ ·2H₂O (3) have been isolated from the reactions of Cu(ClO₄)₂ ·6H₂O (or Cu(NO₃)₂ ·3H₂O), the appropriate amine and Na₂ox in water and have been characterized by IR and electronic spectroscopy and magnetic measurements. The crystal structure of [(Cu(N,N' -dieten)H₂O)₂ ox](ClO₄)₂.H₂O (1) has been determined by single-crystal X-ray analysis. The structure of ( 1 ) consists of binuclear cations [(N,N'-dieten)H₂O)Cu(ox)Cu(N,N'-dieten)H₂O)]²⁺, perchlorate anions and water molecules of crystallization. The copper atom is coordinated by two oxygen atoms of the oxalato ligand, two nitrogen atoms belonging to N,N'-dieten and one oxygen atom of water in a distorted square-pyramidal arrangement. The temperature dependence of magnetic susceptibilities (78-293 K) was measured for 1-3 . Magnetochemical measurements show that copper(II) ions in these compounds are antiferromagnetically coupled with J = -172 cm^-1, -172 cm^-1 and -168 cm^-1 (H = -2JS ₁ S ₂, S ₁= S ₂ = 1/2) for 1, 2 and 3, respectively.

Keywords:

• Copper(II) Complexes
• Oxalato-bridged Complexes
• Magnetic Properties
• Crystal Structure