Influence of substituent effects on spectroscopic properties and antimicrobial activity of 5-(4'-substituted phenylazo)-2-thioxothiazolidinone derivatives

5-(4'-substituted phenylazo)-2-thioxothiazolidinone derivatives (HLn) have been synthesized and characterized by elemental analysis, spectra (IR, electronic and H-1 NMR). The IR spectral data indicate that the compounds can exist in two resonance structures. The synthesized ligands were screened for their antimicrobial activity against four bacterial species, two Gram positive bacteria (Bacillus cereus and Staphylococcus aureus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) as well as against some species various of fungi; Aspergillus niger, Penicillium chrysogenum, Penicillium italicum and Fusarium oxysporium. The results showed that most these ligands are good antibacterial agents against B. cereus and S. aureus and antifungal agents against A. niger and F. oxysporium. HL3 was found to be the most effect compound against all tested microorganisms. The size of clear zone were ordered as follows p-(OCH3 < CH3 < H < Cl < NO2) as expected from Hammett's constant sigma(R).