title: A dinuclear copper(II) complex with adeninate bridge ligands and prominent DNA cleavage activity. Structural and spectroscopic characterization and magnetic properties.
abstract: A new dinuclear copper(II) complex has been synthesized and structurally characterized: [Cu(mu-ade)(tolSO3)(phen)]2.2H2O (Hade = adenine, tolSO3- = toluenesulfonate anion). Its magnetic properties and electronic paramagnetic resonance (EPR) spectra have been studied in detail. The compound has two metal centers bridged by two adeninate NCN groups. The coordination geometry of the copper(II) ions in the dinuclear entity is distorted square pyramidal, with the four equatorial positions occupied by two phenanthroline N atoms and two N atoms from different adenine molecules. The axial position is occupied by one sulfonate O atom. Magnetic susceptibility data show antiferromagnetic behavior with an estimated exchange constant of -2J = 65 cm-1. The EPR spectrum has been obtained at both X- and Q-band frequencies; a study at different temperatures has been carried out at the latter. Above 20 K, the Q-band spectra are characteristic of S = 1 species with a small zero-field splitting parameter (D = 0.0970 cm-1). A detailed study of the DNA-complex interaction has been performed. The title complex efficiently cleaves the pUC18 plasmid in the presence of reducing agents. Both the kinetics and the mechanism of the cleavage reaction are examined and described herein.
authors.affiliation: Departament de Química Inorgànica, Facultat de Farmàcia, Universitat de València, 46100-Burjassot, Spain.
authors.forename: José Luis
authors.initials: JL
authors.lastname: García-Giménez
authors.forename: Gloria
authors.initials: G
authors.lastname: Alzuet
authors.forename: Marta
authors.initials: M
authors.lastname: Gonzalez-Alvarez
authors.forename: Alfonso
authors.initials: A
authors.lastname: Castiñeiras
authors.forename: Malva
authors.initials: M
authors.lastname: Liu-Gonzalez
authors.forename: Joaquín
authors.initials: J
authors.lastname: Borras
mesh_terms: D000225:Adenine / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D006860:Hydrogen Bonding; D007700:Kinetics; D008024:Ligands; D008280:Magnetics; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D003300:Copper; D004247:DNA; D000225:Adenine