Correlation between the structure and biological activity studies of supramolecular coordination azodye compounds

A series of novel bidentate azodye quinoline ligands were synthesized with various p-aromatic amines like p-(OCH3, CH3, H, Cl and NO2). Novel azodye (HLn) and complexes [Cu(II)/Ni(II)] of these ligands have been characterized on the basis of elemental analysis, molar conductance and magnetic measurements, infrared and electronic spectral studies. Suitable structures have been proposed for these complexes. The synthesized ligands and their metal complexes were screened for their antimicrobial activity against four local 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 four local fungal species; namely Aspergillus niger, Alternaria alternata, Penicillium italicum and Fusarium oxysporium. The tested compounds have good antibacterial activity against B. cereus, E. coli and K. pneumoniae. Very low effect was detected against S. aureus and F. oxysporium. We found that the results of antifungal activity of HLn revealed that the complexes are more toxic than ligands against fungi due to the transition metal involved in the coordination. Also Cu2+ complexes are more active than Ni2+ complexes against B. cereus, E. coli and K. pneumoniae. The size of the clear zone was in the following order p-(OCH3 < CH3 < H < Cl < NO2) as expected from Hammett's constants sigma(R). (C) 2013 Production and hosting by Elsevier B.V. on behalf of King Saud University.