Metal complexes of Sulphadimidine(SAD) were synthesized.The complexes were formulated as [Co(SAD)2Cl2], [Cu(SAD)2 (H2O)2], [Ni (SAD)2 Cl2 H2O], [Cd (SAD)2 Br2], [Fe (SAD)3](H2O)3 and [Mn (SAD)2Cl2] characterized by elemental Analysis, conductivity, IR , UV-Vis, Magnet moment and 1H-NMR and Mass spectroscopies. Co(II), Mn (II), and Ni(II) sulphadimidine complexes consist of metal ion which coordinates through amino nitrogen of the terminal NH2 group and oxygen of sulfonamidic group of
the two molecules of sulphadimidine ligand and two halide ions to form octahedral
structure while Cd(II) coordinates with sulphadimidine through amino nitrogen of the
terminal NH2 group with two bromine ions to complete tetrahedral structure. In Cu(II)
sulphadimidine complex, copper ion coordinates through both pyrimidinic nitrogen
(heterocyclic nitrogen) and sulfonamidic nitrogen of the two molecules of sulphadimidine.
Fe(III) coordinates to three molecules of sulphadimidine through heterocyclic nitrogen
(pyrimidinic nitrogen) and sulfonamidic nitrogen,with three molecules of water outside
the coordination sphere. Both Fe(III) and Cu(II) complexes exhibit octahedral geometry.
The antibacterial activity of the complexes and the ligands was investigated against
Esherichia coli, Staphylococcus aureus and Klebsiella pneumonia. The data obtained
revealed that the complexes showed greater activity against the three micro-organisms
when compared to parent compound. Stability constant of the complexes were evaluated
for the metal salts, the order of stability constant β was found to be Cu (II) > Fe (III)
>Ni(II)> Co (II) > Cd (II).The values of stability constant (β) was found to be log 6.31,
5.93, 5.29, 4.63 and 3.92, respectively. The stability constant data revealed that this
ligand may be used as antidote or chelating agent for medical treatment of metals
overload or poisoning.
