Structural diversities and spectroscopic properties of bis and tris(1,10-phenanthroline)copper(II) complexes

The crystal structures of four new compounds containing his and tris(1,10-phenanthroline)copper(II) complex units have been determined by X-ray crystallographic methods; [Cu(phen)(3)](S4O6)(S-8) (1), [Cu(phen)(3)](BF4)(2) (2), [Cu(phen)(2)(OS2O7)] (3) and [Cu(phen)(2)(FBF3)](BF4) (4). The crystal structures of 1 and 2 are composed of discrete [Cu(phen)(3)](2+) cations, (S4O6)(2-) and BF4- anions. The Cu(II) ion is octahedrally coordinated by the three phen ligands. As a consequence of the Jahn-Teller effect, the two axial Cu-N bonds are longer than the equatorial Cu-N bonds and the CuN6 chromophores appear to be elongated rhombic octahedral with tetragonalities of 0.892 and 0.886 for 1 and 2, respectively. Complexes 3 and 4 consist of mononuclear units, the 5-coordinate Cu(II) environment being distorted square pyramidal (tau = 0.31) and distorted trigonal bipyramidal (tau = 0.66), respectively. The unidentate S2O82- anion in 3 occupies the axial position, while the unidentate BF4_ anion in 4 is coordinated in the trigonal plane. The crystal structures and their electronic properties including IR and EPR spectra are discussed and compared to other relevant complexes based on the Jahn-Teller effect. (C) 2006 Elsevier Ltd. All rights reserved.