Synthesis, Characterization And Screening Of Selected Amine Complexes Of The 5-C5h5)(Co)(Pph3)Fe] For Organometallic Moiety [(Η Antibacterial Activity

The emergence of bacterial resistance to existing antibiotics and other drugs is a worldwide problem. New classes of antimicrobial compounds with complete new mode of action are therefore urgently needed to control the rise of the multidrug resistant pathogens. The objective of this study was to prepare, and characterize halfsandwich organometallic compounds of iron containing amine ligands with similar backbones as drug molecules used in the treatment of TB and to test their biological activities against selected bacteria. Half-sandwich organometallic complexes of the type [{(η5-C5H5)Fe(CO)(PPh3)}2µ-(L)]X2 (L = 1,2-diaminoethane, 1,3diaminopropane and 1,4-diaminobenzene, X = univalent counter-anion such as BF4-) were synthesized by reacting two equivalents of [(η5-C5H5)Fe(CO)(PPh3)(THF)]BF4 with L in dichloromethane. The complexes were isolated by precipitation using hexane as air-stable compounds which were then recrystallized and characterized by FTIR and NMR, spectroscopy, melting point determinations and elemental analysis. The characterized compounds were then subjected to in vitro bioassays to determine antibacterial activities against selected bacteria by agar disc diffusion method against Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli and Staphylococcus aureus with gentamicin as the positive control and 0.1% DMSO as the negative control. The organometallic complexes were found to be potent antibacterial agents. Their minimum inhibitory concentrations were determined through broth microdilution technique and found to inhibit the growth of the bacteria used when at as low concentrations as 6.25mg/ml for L = 1,2-diaminoethane,and 1,3-diaminopropane complexes. They indicated that the complexes (ethylenediamine and propylenediamine complexes), which mimicked ethambutol, were more active against all the bacteria used for this study. The paraphenelenediamine complex was found to have little activity against the bacteria used in this study.