- P-ISSN 1225-0163
- E-ISSN 2288-8985
Polydentate Schiff base ligands 5-Br-BSDT(bis(5-bromosalicylaldehyde)diethylenetriamine) having <TEX>$N_3O_2$</TEX> atoms, 5-Br-BSTT(bis(5-bromosalicylaldehyde)triethylenetetramine) having <TEX>$N_3O_2$</TEX> atoms, 5-Br-BSTP(bis(5-bromosalicylaldehyde)tetraethylenepentamine) having <TEX>$N_3O_2$</TEX> atoms were synthesized. Stability constants of the complexes between these ligands and the metal ions such as Cu(II), Ni(II) and Zn(II) were measured in DMSO by a polarographic method. It was observed that all metal(II) ions employed in this study formed 1 : 1 complexes with Schiff base ligands. Stability constants for the ligands were in the order of Cu(II)>Ni(II)>Zn(II), and for complex formation were in the order of 5-Br-BSTP>5-Br-BSTT>5-Br-BSDT according to the increasing in the number of donor atoms. Both enthalpy and entropy changes are obtained in negative valves. Exothermicity for the complex formation indicated tight binding between the ligands and metal ions. The negative entropy change would be related to the fact that solvent molecules are strongly interacting with the metal complexes.