Synthesis, Characterization and Antibacterial Screening of Schiff Base and It’s Metal (II) Complexes Derived from 3-Aminophenol and Salicylaldehyde

New Schiff base ligand was synthesis via a condensation of the ligands in methanol. The Schiff base were synthesized in 1:2 molar ratio reactions. The complexes [Mn(HL1)2Cl, Cu(HL1)2 and Ni(HL1)2Cl] have been characterized on the basis of FTIR, electronic spectra, melting points/decomposition temperature, solubility and molar conductance. The in-vitro antibacterial activity of the complexes was tested using two gram-negative (Escherichia coli and Salmonella typhimurium) and two gram-positive (Staphylococcus pyogenes and Staphylococcus aureus) bacterial strains. The IR bands of Schiff bases showed a broad-band at 3317 cm-1. The strong bands at 1590 cm-1 range was assigned to v(C=N) vibration which reveals coordination of the carbonyl group of the aldehyde and the amine group of the 3-aminophenol and salicylaldehyde which ascertain the formation of the azomethine bond. The ⱱ(C=N) observed at 1603, 1591 and 1591 cm-1 range in the spectra of the complexes showed a shift to higher frequencies in all the complexes. These show the participation of the azomethine nitrogen in the coordination. The bands at 690, 512 and 512 cm-1were assigned to (M–N) and the bands at 538, 461 and 461 cm-1 were assigned to (M–O). The electronic spectral data of the complexes suggest an octahedral and tetrahedral geometry for all the complexes. The molar conductivity indicates that the synthesized complexes are all non-electrolytes and soluble in protic solvent such as methanol and ethanol. The synthesized metal complexes showed improved broad-spectrum antimicrobial activity against gram-positive and gram-negative bacteria better than the Schiff base. Thus, the complexes should be considered as possible lead compounds to be developed into antibiotics against the tested bacterial strains E. coli, S. typhimurium, S. aureus and S. pyrogens.