Collect. Czech. Chem. Commun. 1990, 55, 2199-2215

Copper(II) complexes with 1-phenyl-4,6-dimethylpyrimidine-2-thione. Chemical, spectroscopic, magnetic, conductivity and polarographic studies

Raffaele Battistuzzi and Marco Borsari

Department of Chemistry, University of Modena, 41100 Modena, Italy


New copper(II) complexes of general composition: CuLX2.nH2O (X = Cl-, n = 0.25; X = NO3-, n = 0.5), Cu2L3Cl4.2H2O, CuL2X2.H2O (X = ClO4-, BF4- and NO3-) and Cu2L7X4 (X = ClO4-, BF4- and NO3-), where L = 1-phenyl-4,6-dimethylpyrimidine-2-thione, have been isolated. Chemical and thermal analyses, conductivity, magnetic susceptibility, infrared and ligand field spectroscopic data and, for the perchlorate complexes also polarographic studies, are reported. Diagnostic IR bands frequencies of counter-ions, χ(Cu-X) modes and ligand field spectra for the mono-and bis-ligand compounds, having an equatorial [CuNSCl2], [CuNSO2] and [CuN2S2] microsymmetry, indicate a coordinating character of some anions, suggesting an elongated octahedral geometry for these complexes. For the [Cu2L7]X4 (X = ClO4-, BF4- and NO3-) complexes, which exhibit at room temperature subnormal magnetic moments, a polynuclear structure with the copper(II) in a roughly square-pyramidal environment, is proposed. Polarographic data for the perchlorate complexes and for the Cu(ClO4)2-L system at various ligand concentrations, have shown that in DMF solution the prevailing species are [CuL2]2+, [CuL3]2+ and [Cu2L7]4+ confirming the oxidation state II for the copper ions in the [Cu2L7]X4 complexes.