Mohamed I. Abou-Dobara

Supramolecular coordination and antimicrobial activities of constructed mixed ligand complexes

A novel series of copper(II) and palladium(II) with 4-derivatives benzaldehyde pyrazolone (L(n)) were synthesized. The mixed ligand complexes were prepared by using 1,10-phenanthroline (Phen) as second ligand. The structure of these complexes was identified and confirm by elemental analysis, molar conductivity, UV-Vis, IR and (1)H NMR spectroscopy and magnetic moment measurements as well as thermal analysis. The ligand behaves as a neutral bidentate ligand through ON donor sites. ESR spectra show the simultaneous presence of a planar trans and a nearly planar cis isomers in the 1:2 ratio for all N,O complexes [Cu(L(n))(2)]Cl(2)⋅2H(2)O. Schiff bases (L(n)) were tested against bacterial species; namely two Gram positive bacteria (Staphylococcus aureus and Bacillus cereus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) and fungal species (Aspergillus niger, Fusarium oxysporium, Penicillium italicum and Alternaria alternata). The tested compounds have antibacterial activity against S. aureus, B. cereus and K. pneumoniae.

Allyl rhodanine azo dye derivatives: Potential antimicrobials target d-alanyl carrier protein ligase and nucleoside diphosphate kinase: ABOU-DOBARA et al.

3‐Allyl‐5‐(4‐arylazo)‐2‐thioxothiazolidine‐4‐one (HLn) ligands (where n = 1 to 3) were hypothesized to have antimicrobial activities mediated through inhibition of new antimicrobial targets. The ligands (HLn) were synthesized and characterized by infrared (IR) and 1H nuclear magnetic resonance (1H NMR) spectra. The ligands (HLn) were in silico screened to their potential inhibition to models of d‐alanyl carrier protein ligase (DltA) (from Bacillus cereus, PDB code 3FCE) and nucleoside diphosphate kinase (NDK) (from Staphylococcus aureus; PDB code 3Q8U). HL3 ligand has the best energy and mode of binding to both NDK and DltA, even though its binding to DltA was stronger than that to NDK. In antimicrobial activity of HL3 ligand, morphological and cytological changes in HL3‐treated bacteria agreed with the in silico results. The HL3 ligand showed significant antimicrobial activity against B. cereus, S. aureus, and Fusarium oxysporium. The HL3‐treated bacterial cells appeared malformed and incompletely separated. Its cell walls appeared electron‐lucent and ruptured. They contained more mesosomes than normal cells. It was found that the HL3 ligand represented as a bactericide against B. cereus and S. aureusby blocking target DltA, and may target NDK.