Synthesis and antibacterial activity of some Schiff base complexes

Abstract

Two Schiff bases were synthesized from raceacetophenone: 1) ADS1 4-ethyl-6-{(E)-1-[(3-nitrophenyl)imino]ethyl}benzene-1,3-diol and 2) ADS3 4-ethyl-6-[(E)-1-{(2-nitrophenyl)imino]ethyl}benzene-1,3-diol. Then their metal complexes were formed. The metals selected for the preparation of complexes were copper, nickel, iron and zinc. Hence, in total 8 metal complexes were synthesized and screened for antibacterial activity against some clinically important bacteria, such as Pseudomonas aeruginosa, Proteus vulgaris, Proteus mirabilis, Klebsiella pneumoniae and Staphylococcus aureus. The in vitro antibacterial activity was determined by the Agar Ditch technique using DMF (polar) and 1,4-dioxane (non polar) as solvents. The Schiff bases showed greater activity than theirmetal complexes; themetal complexes showed differential effects on the bacterial strains investigated and the solvent used, suggesting that the antibacterial activity is dependent on the molecular structure of the compound, the solvent used and the bacterial strain under consideration. The Schiff base ADS3 in the polar solvent DMF showed better antibacterial activity towards the investigated bacterial strains. Amongst the four metals, Zn showed the best antibacterial activity followed by Fe in 1,4-dioxane while Ni followed by Zn and Fe showed the best antibacterial activity in DMF. P. vulgaris was the most resistant bacteria.

Copper(II) complexes of coumarin-derived Schiff bases and their anti-Candida activity

“…3d, 3g and 3j were tested as suspensions and their MIC 50 values were still lower than those of their corresponding free ligands. Previous work by Nair et al reported a series of Mn(II) and Cu(II) complexes which exhibited activities lower than the activities of their corresponding free ligands when tested using separately 1,4-dioxane and DMF as solvent [72]. This present study has identified a series of coumarin-derived Schiff bases and their Cu(II) complexes who have displayed good antifungal activity against a clinical strain of C. albicans.…”

Anticancer and antifungal activity of copper(II) complexes of quinolin-2(1H)-one-derived Schiff bases

“…Despite these findings, it is difficult to identify a structure activity relationship (SAR) with respect to electronic and steric properties of a compound. It was found that substitution of a methoxy group (15) in place of ethoxy group (14) had little effect on activity indicating that the bulky nature of the substituent has no effect on the activity of a compound at this position. It may prove difficult to identify a real SAR when the target of the ligands remained unidentified to date.…”

“…Transition metal complexes of Schiff bases have attracted a lot of interest due to their potent biological activities such as antifungal, antibacterial, anticancer and herbicidal applications [12][13][14][15][16]. These studies have shown that 0020-1693/$ -see front matter Ó 2010 Elsevier B.V. All rights reserved.…”

Synthesis, Surface Properties and Antimicrobial Activity of Some Germanium Nonionic Surfactants

“…The diameters of inhibition zones were measured after 24-48 hours at 35-37 for bacteria and 3-4 days at [25][26][27] for yeast and fungi of incubation at 28 , with subsequent filtering to remove mycelia fragments before the solution containing the spores was used for inoculation.…”

“…The chemical structure of these molecules is the main factor influencing their thermodynamic aspects. The equivalence between adsorption and micellization tendencies qualifies these surfactants as being applicable in the interfacial applications including emulsification, corrosion inhibition, and biocidal application 26 .…”