title: Synthesis, structure and biological activity of copper(II) complexes with oxolinic acid.
abstract: The neutral mononuclear copper complexes with the quinolone antibacterial drug oxolinic acid in the presence or not of a nitrogen donor heterocyclic ligand 1,10-phenanthroline, 2,2'-bipyridine or 2,2'-dipyridylamine have been synthesized and characterized with infrared, UV-visible and electron paramagnetic resonance spectroscopies. The experimental data suggest that oxolinic acid acts as a deprotonated bidentate ligand and is coordinated to the metal ion through the pyridone and one carboxylate oxygen atoms. The crystal structure of (chloro)(1,10-phenanthroline)(oxolinato) copper(II), 2, has been determined with X-ray crystallography. For all complexes a distorted square pyramidal environment around Cu(II) is suggested. The EPR (electron paramagnetic resonance) behavior of 2 in aqueous solutions indicates mixture of dimeric and monomeric species. The investigation of the interaction of the complexes with calf-thymus DNA has been performed with diverse spectroscopic techniques and showed that the complexes are bound to calf-thymus DNA. The antimicrobial activity of the complexes has been tested on three different microorganisms. The complexes show a decreased biological activity in comparison to the free oxolinic acid.
authors.affiliation: Institute of Physical Chemistry, NCSR Demokritos, 15310 Aghia Paraskevi, Attikis, Greece. gpsomas@chem.demokritos.gr <gpsomas@chem.demokritos.gr>
authors.forename: George
authors.initials: G
authors.lastname: Psomas
authors.forename: Alketa
authors.initials: A
authors.lastname: Tarushi
authors.forename: Eleni K
authors.initials: EK
authors.lastname: Efthimiadou
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Sanakis
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Raptopoulou
authors.forename: Nikos
authors.initials: N
authors.lastname: Katsaros
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects; D002417:Cattle; D002942:Circular Dichroism; D003300:Copper / Q000737:chemistry* / Q000494:pharmacology; D004247:DNA / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D010093:Oxolinic Acid / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D013056:Spectrophotometry, Ultraviolet
chemical_list: D009942:Organometallic Compounds; D003300:Copper; D004247:DNA; C427203:calf thymus DNA; D010093:Oxolinic Acid