Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

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.