UV-VIS AND EPR SPECTROSCOPIC STUDY OF COPPER(II) COMPLEXES WITH BIS(BENZIMIDAZOL-2-YL) LIGANDS

Copper(II) complexes with bis(benzimidazol-2-yl) ligands of the type Bz(CH2)n-X-(CH2)(n)Bz (where Bz = benzimidazol-2-yl; X = 0, S or CH2; n = 1, 2) have been characterized in solution by UV-Vis and EPR spectroscopy. Mono complexes with O or S donor atom containing ligands have square-pyramidal stereochemistries, while bis complexes have pseudo-octahedral geometries with four nitrogen donors in the equatorial plane and the two heteroatoms occupying the apical positions. The mono and bis complexes with the ligand having X = CH2 and n = 2 have distorted octahedral geometries with two molecules of solvents involved in the apical positions. The experimental results on the complexes with the ligand having X = CH2 and n = 1 suggest that this ligand behaves as monodentate.