Influence of the counterion on the geometry of Cu(I) and Cu(II) complexes with 1,10-phenanthroline

Abstract

The influence of the counterions on the geometry of Cu(I) and Cu(II) unsubstituted phen-based (phen=1,10-phenanthroline) complexes was investigated. The synthetic strategy used afforded the synthesis of both the tetracoordinated Cu(I) and pentacoordinated Cu(II) species with general formula [(phen)2Cu]+Y− (Y−=ClO4−, I−, SCN− and BF4−) and [(phen)2CuX]+Y− (X=Cl−, I−, NCS−, and Y−=ClO4−, I−, SCN− and BF4−), respectively. The firstly isolated Cu(I) complexes were characterized by IR, 1H NMR and UV-Vis spectroscopies, their proposed structures being confirmed by elemental analysis, atomic absorption spectroscopy (AAS) and thermogravimetric analysis (TGA). The molecular structure of Cu(II) complexes was determined by single crystal X-ray diffraction analysis. While for Cu(I) complexes, the coordinating nature of the counterions seems to have a strong influence (observed in the solid state and concentrated solution) on the flattening distortion (D2d→D2) of the geometry about the Cu(I) ion, in the Cu(II) derivatives, the size, shape, number and type of intermolecular interactions established by the counterions, drive not only the overall cations supramolecular organization, but also the molecular stereochemistry around the Cu(II) ion.