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

Journal article, 2002

Three new binuclear μ-oxalato copper(II) complexes of composition [(Cu(N,N'-dieten) H2O2ox](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)2ox](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 (78-293K) 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 = -2JS1S2, S1 = S2 = 1/2) for 1, 2 and 3, respectively.