Biologically vital metal-based antimicrobial active mixed ligand complexes: synthesis, characterization, DNA binding and cleavage studies


Research Department of Chemistry, VHNSN College, Virudhunagar-626 001, India


Few novel cobalt(II) and copper(II) complexes [M(fmp)3]Cl2, [M(fmp)(bpy)2]Cl2,
[M(fmp)(phen)2]Cl2 and [M(fmp)(phen)(bpy)]Cl2 (fmp = 3-furan-2-ylmethylene-pentane-2,4-
dione, phen = 1,10-phenanthroline, bpy = 2,2'-bipyridine) have been synthesized and
characterized by elemental analyses, molar conductance, magnetic susceptibility measurements,
IR, electronic, EPR, mass spectra and cyclic voltammetric studies. The synthesized complexes
are found to be monomeric and electrolytic nature. The UV-Vis., magnetic susceptibility and
EPR spectral data of the complexes suggest a distorted octahedral geometry for Cu(II)
complexes and octahedral geometry for Co(II) complexes around the central metal ion. The CV
profile of the complexes shows a quasi-reversible peak which indicates that the metal-ligand
linkage is more covalent in nature. Spectroscopic and viscosity measurements prove that the
[M(fmp)(phen)2]Cl2 complexes bind more efficiently with DNA than other complexes through
intercalative mode. The difference of peak potential and electrochemical parameters between
free and DNA-bound complexes shows the formation of an electrochemical active complex
between synthesized complexes and DNA. All the complexes cleave the Supercoiled pUC19
DNA in vitro under the presence of reducing agent (3-mercaptopropionic acid). The in vitro
antimicrobial activities of the compounds have been tested against the bacterial and fungal
strains using the disc diffusion method. The minimum inhibitory concentration (MIC) values
against the growth of microorganisms are much larger for metal chelates than the individual


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