title: Superoxidedismutase-mimetic copper(II) complexes containing saccharinate and 4-aminopyridine/4-cyanopyridine.
abstract: Two copper(II) complexes, [Cu(sac)(2)(4-cypy)(2)(H(2)O)], 1 and [Cu(sac)(2)(4-Ampy)(2)(H(2)O)], 2 (4-cypy: 4-cyanopyridine; 4-Ampy: 4-aminopyridine) were prepared. Physicochemical properties of the complexes were studied by spectroscopic (solution UV-vis, diffuse reflectance and IR) techniques. Structural X-ray diffraction data could be obtained only for [Cu(sac)(2)(4-cypy)(2)(H(2)O)] that it crystallized in the tetragonal space group P4cc with a=b=15.313(1), c=13.240(1)A, and Z=4 molecules per unit cell. The complex was cited on a crystallographic C(2)-axis with the Cu(II) ion in a square-pyramidal environment, coordinated at the pyramid basis to the nitrogen atom of two saccharine anions [d(Cu-N)=2.011(3)A] and the pyridine N-atom of two 4-cyanopyridine ligands [d(Cu-N)=2.038(4)A]. The coordination was completed by a water molecule at the pyramid apex [d(Cu-Ow)=2.189(5)A]. Elemental and spectroscopic analyses revealed an O-saccharinate coordination mode for complex 2 and a square-pyramidal structure. Only complex 2 retained its structure in methanolic solution. However, both complexes were able to catalyze the dismutation of superoxide anion (O(2)(-)) (pH 7.5) at micromolar concentrations. Therefore, these complexes behaved as useful SOD-mimetic compounds.
authors.affiliation: Centro de Química Inorgánica (CEQUINOR/CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C. Correo 962, 1900 La Plata, Argentina.
authors.forename: Evelina G
authors.initials: EG
authors.lastname: Ferrer
authors.forename: Natalia
authors.initials: N
authors.lastname: Baeza
authors.forename: Luciana G
authors.initials: LG
authors.lastname: Naso
authors.forename: Eduardo E
authors.initials: EE
authors.lastname: Castellano
authors.forename: Oscar E
authors.initials: OE
authors.lastname: Piro
authors.forename: Patricia A M
authors.initials: PA
authors.lastname: Williams
mesh_terms: D015761:4-Aminopyridine / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D009570:Nitriles / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry; D013482:Superoxide Dismutase / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D009570:Nitriles; D011725:Pyridines; D015761:4-Aminopyridine; C494727:4-cyanopyridine; D013482:Superoxide Dismutase