Five novel copper(II) complexes derived from the condensation between 5-bromosalicyaldhyde (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, thermogravemetric analysis, IR, electronic spectra and
conductance and magnetic measurements. Moreover, the stoichiometry and the stability constants of the prepared complexes have been determined spectrophotometrically. The Results indicated that the Schiff base of the amino acids L-alanine, L-phenylalanine, L-histidine and L-arginine behaves as tridentate ligand, coordinating the copper(II) via azomethine nitrogen, deprotonated carboxylate oxygen and phenolic oxygen.While in the case of L-aspartic, the ligand acts as tetradentate due to the coordination of the second carboxylate group. Based on the studies of magnetic moments and electronic spectra, a square planar geometry has been proposed for all copper complexes except bromsalicylaldehydine aspartate complex has a distorted tetrahedral structure. The representative Schiff bases and their copper complexes were tested in vitro for their antibacterial activity against two Gram- Positive bacteria (micrococous, Bacillus cereus) and one Gram-negative bacteria (Pseudomonas aeruginosa). All the complexes showed activity against the organisms more than the free Schiff base ligands and the activity increases with the increase in concentration of test solution containing the new complexes. The binding of the prepared Schiff base amino acid cooper(II) complexes to calf thymus DNA has been investigated by absorption spectra and viscosity measurement and the mode of CT-DNA binding to the complexes has been explored. The results indicated that investigated complexes couldbind to DNA via classical intercalative mode and follow the trend: bsarc > bshc > bsalc > bsphalc > bsasc.