title: Nickel-quinolones interaction: part 3--Nickel(II) complexes of the antibacterial drug flumequine.
abstract: Nickel(II) complexes with the first-generation quinolone antibacterial agent flumequine in the presence or absence of nitrogen donor heterocyclic ligands (4-benzylpyridine, pyridine, 2,2'-bipyridine or 1,10-phenanthroline) have been structurally characterized by physicochemical and spectroscopic techniques. The experimental data suggest that flumequine acts as deprotonated bidentate ligand coordinated to Ni(II) through the carboxylato and ketone oxygen atoms. The crystal structures of bis(4-benzylpyridine)bis(flumequinato)nickel(II) 2, (2,2'-bipyridine)bis(flumequinato)nickel(II) 4 and (1,10-phenanthroline)bis(flumequinato)nickel(II) 5 have been determined by X-ray crystallography and are the first crystal structures of flumequinato complexes reported. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that the complexes bind to CT DNA and bis(aqua)bis(flumequinato)nickel(II) exhibits the highest binding constant to CT DNA. Competitive study with ethidium bromide (EB) has shown that the complexes can displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB. The cyclic voltammograms of the complexes recorded in DMSO solution and in 1/2 DMSO/buffer (containing 150 mM NaCl and 15 mM trisodium citrate at pH 7.0) solution have shown that in the presence of CT DNA they bind to CT DNA by the intercalative binding mode. The complexes exhibit good binding propensity to human or bovine serum albumin protein having relatively high binding constant values.
authors.affiliation: Department of General and Inorganic Chemistry, Faculty of Chemistry, Aristotle University of Thessaloniki, P.O. Box 135, GR-54124 Thessaloniki, Greece.
authors.forename: Kalliopi C
authors.initials: KC
authors.lastname: Skyrianou
authors.forename: Franc
authors.initials: F
authors.lastname: Perdih
authors.forename: Iztok
authors.initials: I
authors.lastname: Turel
authors.forename: Dimitris P
authors.initials: DP
authors.lastname: Kessissoglou
authors.forename: George
authors.initials: G
authors.lastname: Psomas
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002417:Cattle; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry; D024841:Fluoroquinolones / Q000737:chemistry*; D006801:Humans; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D015363:Quinolones / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D009942:Organometallic Compounds; D015363:Quinolones; D009532:Nickel; D004247:DNA; C427203:calf thymus DNA; C012976:flumequine