Synthesis, Spectroscopic Characterization, and Biological Evaluation of Mixed Ligands Complexes From Schiff Base and 1,10-Phenanthroline With Multivalent Metal Ions

The new Schiff base (L) was synthesized from the condensation reaction of 3-amino-4-(1-methoxy-1-oxo-3-phenylpropane-2-ylamino)-4-oxobutanoic acid (aspartame) with 4-chlorobenzaldehyde in 3 drops of glacial acetic acid. This ligand is characterized by techniques: UV-Vis, FT_IR, 1HNMR, 13CNMR, Mass and C.H.N.O. A series of complexes were prepared with 1,10- phenanthroline as mixed ligands complexes. All mixed ligands complexes of chromium, cobalt, nickel, copper, palladium and platin have been characterized by the same ligands techniques. In addition to molar conductivity and magnetic moments, the NMR spectrum and mass spectrum were for ligands only. Results showed through previous techniques that the ligand (L) behaves as tetra dentate chelated ligand and binds to the metal ions through (N, O) with all the prepared complexes except for the palladium complex with the (N) atom only. Whereas in 1,10-phenanthroline coordinated by two nitrogen atoms as bidentate ligand. Two varieties of bacteria-gram positive (Staphylococcus aureus and Bacillus subtilis) and gram negative (Escherichia coli and Acinetobacter baumannii) as well as one type of fungus candida albicans at a concentration of 0.02 M were used to study the biological activity. The findings demonstrated that, in comparison to standard drugs and 1,10-phenanthroline, the produced ligand and metal complexes exhibit stronger inhibition of all species of bacteria and fungi. The standard (ΔHf0) and (ΔE0) of all prepared compounds were computed using the Hyper – Chem 8.0.7 program. Additionally, vibration frequencies, HOMO and LUMO for the ligand only to determine the active sites in molecule and the coordination regions that are likely to occur.