Background: In this paper, all the complexes with the general formulae I(a-e) [MLCl2H2O] and II(a-e) [ML2]Cl2, were synthesized from divalent metal ions Co, Ni, Cu, Zn, or Mn with Schiff base (HL) which derived from cephalexin and isatin in the ratio of metal to ligand 1:1 for the primer and 1:2 for the later, this ligand Schiff base was tridentate NNO Schiff base. Complexes were characterized by elemental analysis, molar conductance and magnetic susceptibility measurements, electronic, FT-IR and 1HNMR spectral studies.
Objective: The aim of this work was the synthesis of a novel Schiff base derived from cephalexin and isatin and synthesis of ten new complexes derived from this Schiff base and divalent metal ions (CO, Ni, Cu, Zn and Mn) in (1:1) ratio for complexes I(a-e) and (1-2) ratio for complexes II(a-e), and to test their antibacterial activity.
Methodology: The α-amino group of the cephalexin (Ceph) antibiotic was directly undergone nucleophilic addition into a Schiff base ligand when it was refluxed in ethanolic solution with isatin using an acid catalyst. This ligand was coordinated with divalent metal ions with ratio (1:1) and (1:2), by its refluxing in ethanolic solution to form the title complexes.
Results and Discussion: The chemical structures of the new ligand Schiff base and the neutral nonelectrolyte octahedral geometry of complexes I (a-e) and electrolyte octahedral geometry of complexes II(a-e) were confirmed through (1HNR, FT-IR, U.V. and electronic spectra) in addition to elemental microanalysis, magnetic susceptibility and molar conductivity.
Conclusions: The Schiff bases ligand derived from Cephalexin (Ceph) with isatin and its complexation with divalent metal ions in (1:1) and (1:2) molar ratio of metal ion to ligand showed the interesting synthesis of simple procedures, high yields and good confirmation by all analysis methods with octahedral geometry and nonelectrolyte nature of complexes I(a-e) and electrolyte nature of complexes II(a-e). They have exhibited no antibacterial activity against Pseudomonas bacteria, but they exhibited minimum inhibitory concentration (MIC) (μg/ml) values against E.coli., especially those of manganese complexes I (e) and II (e), which displayed this activity at all concentrations.