Synthesis, crystal structure and electronic properties of bis(N-2-bromophenyl-salicydenaminato)copper(II) complex

A new series of complexes of the type bis(N-substituted-salicydenaminato)copper(II) (1-9), have been synthesized and characterized by IR, UV-Vis and elemental analysis methods. The molecular structure of bis(N-2-bromophenyl-salicydenaminato)copper(II) (6), was determined using X-ray crystallography. There are two independent molecules in the structure. Each shows a neutral, mononuclear, four-coordinate, square-planar trans-Cu[N₂O₂] geometry and, in each, the Cu atom and the ligating atoms are coplanar. The chelating N-Cu-O angle is 91.39(11)° for molecule one and 91.20(11)° for molecule two, whereas the non-chelating N-Cu-O angles are 88.61(11) and 88.80(11)°, respectively. The trans-N-Cu-N and trans-O-Cu-O bond angles are 180°. The electronic absorption spectra of copper(II) complexes (1-9), indicate that the d-d band energy is dependent on the nature and position of substituent on phenyl ring of the salicyldenimine ligand. The UV-Vis spectra in various solvents were measured and a relationship between absorption spectra and dielectric constant of the solvents is reported.