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

The crystal structures of four new compounds containing bis and tris(1,10-phenanthroline)copper(II) complex units have been determined by X-ray crystallographic methods; [Cu(phen)3](S4O6)(S8) (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 (τ = 0.31) and distorted trigonal bipyramidal (τ = 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.

Graphical abstractThe crystal structures of bis and tris(1,10-phenanthroline)copper(II) complexes [Cu(phen)3](S4O6)(S8) (1), [Cu(phen)3](BF4)2 (2), [Cu(phen)2(OS2O7)] (3) and [Cu(phen)2(FBF3)](BF4) (4) have been determined by X-ray crystallography. The Cu(II) ions are 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 (τ = 0.31) and distorted trigonal bipyramidal (τ = 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 (IR and EPR) are discussed and compared to other relevant complexes based on the Jahn-Teller effect.Figure optionsDownload full-size imageDownload as PowerPoint slide