ABSTRACT

The synthesis, characterization and preliminary antimicrobial studies of some novel Schiff base ligands;  N,N/ - Bis(2-hydroxybenzylidene)-1,4-phenylenediimine(M) and N,N/ - Bis(4-dimethylaminobenzylidene)-1,4-phenylenediimine (N)  were undertaken. It was prepared by the condensation reaction of 1,4-phenylenediamine with 4-dimethylaminobenzadehyde and 2-hydroxybenzaldehde .Their Co(II), Mn(VII), Mo(VII) metal complexes were synthesized by coupling them respectively with the individual formed ligands. These ligands and their complexes were characterized on the basis of their melting point, stoichiometry, electronic spectra, infrared spectra and antimicrobial their antimicrobial properties. Spectrophotometric analysis gave the stoichiometry to be 1:1 metals to ligand mole ratio for the Co(II) and Mn(VII)  complexes of the N,N/ - Bis(2-hydroxybenzylidene)-1,4-phenylenediimine(M)  ligand and a 1:2 metal to ligand mole ratio for its Mo(VII) complex. Secondly its N,N/ - Bis(4-dimethylaminobenzylidene)-1,4-phenylenediimine (N) ligand gave a 2:3 metal   to ligand mole ratio for its Co(II) complex, a 1:4 ratio for its Mn(VII), and a 1:1 ratio for  Mo(VII) complexes.  Based on their spectral studies  the ligandN,N/Bis(2-hydroxybenzylidene)-1,4-phenylenediimine(M) was observed to be bidentate through the participation of the oxygen from their hydroxyl endand N,N/ - Bis(4-dimethylaminobenzylidene)-1,4-phenylenediimine (N) was bidentate through the participation of their imine nitrogen end. The ligand and its complexes were tested against Candida albicans , Escherichia coli,Salmonella typhi, Enterococcus feacalis and Staphylococcus aureus  with dimethylformamide (DMF) as the control. These screening were performed at different concentrations by the agar-well diffusion method and the gram negative organism showed activity that the metal complexes are more potent than the parent Schiff base ligand.