Five novel Cu(II) complexes derived from the condensation between 5-bromosalicylaldehyde (bs) and
α-amino acids (L-alanine, L-phenylalanine, L-aspartic acid, L-histidine and L-arginine) were synthesized and characterized by their elemental analyses, thermogravimetric analysis, IR, mass and electronic spectra, conductance and magnetic measurements. Moreover, the stoichiometry and the stability constants of the prepared complexes have been determined spectrophotometrically using continuous variation and molar ratio methods. The obtained results indicated that the Schiff bases of the amino acids: L-alanine, L-phenylalanine, L-histidine and L-arginine behave as tridentate ligands. The ligands are coordinating with the Cu(II) via azomethine nitrogen,
deprotonated carboxylate oxygen and phenolic oxygen However, in the case of L-aspartic, the ligand acts as tetradentate due to the coordination of the second carboxylate group.