Superoxidedismutase-mimetic copper(II) complexes containing saccharinate and 4-aminopyridine/4-cyanopyridine

EVELINA G. FERRER,, NATALIA BAEZA, LUCIANA G. NASO , EDUARDO E. CASTELLANO, OSCAR E. PIRO, PATRICIA A.M. WILLIAMS

JOURNAL OF TRACE ELEMENTS IN MEDICINE AND BIOLOGY

ELSEVIER GMBH

Lugar: Alemania; Año: 2010 vol. 24 p. 20 - 26

0946-672X

Two copper(II) complexes, [Cu(sac)2(4-cypy)2(H2O)], 1 and [Cu(sac)2(4-Ampy)2(H2O)], 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(H2O)] 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 C2-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 (O2-) (pH 7.5) at micromolar concentrations. Therefore, these complexes behaved as useful SOD-mimetic compounds.