Thermal Properties, Antimicrobial Activity of Azo Complexes and Ultrastructure Study of Some Affected Bacteria

Abstract

A series of copper (II) complexes of bidentate azo rhodanine ligands (HLn) have been synthesized and characterized. The IR spectral and thermogravimetric analysis are used to characterize the isolated complexes. X-ray diffraction patterns show polycrystalline nature for as-synthesized ligand HL2 and its complex. Quantum chemical parameters, absolute hardness, global electrophilicity and additional electronic charge were calculated for HLn. Copper(II) complexes (1-4) are tested against four local bacterial species; namely two Gram positive bacteria (Staphylococcus aureus and Bacillus cereus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) and against four local fungal species (Aspergillus niger, Fusarium oxysporium, Penicillium italicum and Alternaria alternata). The tested complexes have good antibacterial activity against Staphylococcus aureus and Escherichia coli and have low antifungal activity against Aspergillus niger, Fusarium oxysporium and Alternaria alternata. We found that the complex (3) is more active than other complexes against Staphylococcus aureus and Escherichia coli as expected from Hammett's substituent coefficients (σR). Ultrastructure studies of the affected Staphylococcus aureus and Escherichia coli confirmed that complex (3) has bactericidal effect.

Review on the Antibacterial Mechanism of Plant-Derived Compounds against Multidrug-Resistant Bacteria (MDR)

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