European Journal of Biomedical and Pharmaceutical Sciences

SYNTHESIS, CHEMICAL ANALYSIS AND ANTIMICROBIAL STUDIES OF PLATINUM AND COPPER COMPLEXES OF CONDENSATES OF SALICYLALDEHYDE AND 2-HYDROXYANILINE

Anumata S. E.*, Ezenweke L. O. and Orjiako E. N.

ABSTRACT

The incidence of drug resistance to microbes causing diseases to man and animal, even plants have necessitated further research towards development of molecular compounds that would break the barrier of resistance, guarantee safety and potency of pharmaceutical products. This study synthesis, chemical analysis and antimicrobial studies of Platinum(II) and Copper (II) as well as their mixed ligand of 2-Phenyliminomethylphenol (PMP) and 2,2-Hydroxybenzylideneaminophenol (HAP) is one of such attempts of development of new molecular compounds capable of breaking the barrier of resistances. The PMP and HAP were prepared by reacting Aniline and 2-aminophenol with salicylaldehyde respectively. The unmixed metal complexes were prepared by addition of either of 0.29 mmol 2-phenyliminomethylphenol ligand into the metal salt or 0.29 mmol 2,2-hydroxybenzylideneaminophenol ligand into the metal salt, while the mixed metal complexes were prepared by addition of equimolar amount of ligands of 2-Phenyliminomethylphenol and 2,2-Hydroxybenzylideneaminophenol into the metal salt. The molecular structures of the ligand and their complexes have been determined and characterized using spectroscopic techniques which includes GC-MS, FTIR, UV-Vis, 1HNMR, and X-Ray Diffraction studies. The melting point and solubility of the ligands and complexes synthesized were equally determined. Antimicrobial Screening were carried with ligands PMP and HAP and the metal complexes using clinical isolates of Gram Positive Bacteria (Staphylococcus aureus and Bacillus substilis), Gram Negative Bacteria (Escherichia coli and Pseudomonas aeruginosa) and Fungi (Candida albicans and Aspergillus niger). All complexes and ligands were found to be soluble in dimethylsulfoxide (DMSO). The molecular ion, molecular weight and molecular formula of the synthesized ligands and metal complexes were detected using the various fragments produced by the ligands and metal complexes based on their mass to charge ratio obtained from GC-MS spectra. Asymmetric octahedral geometry was observed for both Platinum(II) and Copper(II) complexes with PMP, HAP, and mixed ligands. A bidentate ligand is coordinated to the metal ions through oxygen atoms of carbonyl groups and nitrogen atoms of two imine groups for Platinum(II) and Copper(II) complexes. The XRD pattern indicates that the ligand and metal complexes are crystalline with high crystallite size of 119.23 nm to 638.67 nm. The FTIR spectra for 2-phenyliminomethylphenol (PMP) showed absorbance at the band 1569.2cm-1 as indicated by the stretching C=C bond in the benzene rings, bands at 1613.9 cm-1 as indicated by =C-N stretching in the benzene ring were actually observed. The electronic spectra of the complexes formed showed energy absorbed in the ultraviolet/visible region produced changes in the electronic energy of the compound resulting from transition of valence electrons in the complexes. The XRD results indicate the crystal formed by the ligands and their respective complexes are large. However, the ligands had higher size compared to the complexes formed, which could be due to the complexation reactions. X-Ray Diffractograms of the metal complexes investigated showed good intense peaks indicating high crystallinity. The ligand of 2-Phenyliminomethylphenol (PMP) and 2,2-hydroxybenzylideneaminophenol (HAP) showed partial inhibitory action on the clinical isolates of Gram Postive, Gram Negative and no inhibitory action on the Fungi while metal complexes of Pt(II), both mixed and unmixed showed either strong or stronger inhibition. Copper(II) was found to differ as its complexes all exhibited stronger inhibition on the clinical isolates of Gram Positve, Gram Negative and Fungi isolates. It was concluded that the synthesized ligands and complexes are purely crystalline as revealed by the chemical analysis, exhibited inhibitory actions on Gram Positive, Gram Negative and Fungi Species.

Keywords: 2-Phenyliminomethylphenol, Metal complexes, Salicylaldehyde, 2-hydroxyaniline, Ligands.