Copper(II) complexes as superoxide dismutase mimics: Synthesis, characterization, crystal structure and bioactivity of copper(II) complexes

• Published in: Inorganica Chimica Acta 2009-11, Vol.362 (14), p.4891-4898
• Main Authors: Patel, R.N., Shukla, K.K., Singh, Anurag, Choudhary, M., Chauhan, U.K., Dwivedi, S.
• Format: Article
• Language: English
• Subjects: Copper(II) complexes; Superoxide dismutase (SOD) activity; X-band EPR
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2009.07.037

Two new copper(II) complexes of the type [Cu(L)X 2), where PSBP = 4-phenyl semicarbazide-2-benzoylpyridine and X = Cl/Br have been synthesized and characterized by elemental analyses, magnetic measurements, electronic absorption, conductivity measurements and epr spectroscopy. The crystal structures (1) of these complexes have been successfully determined and are turn out to be CuN 3OCl 2 or CuN 3OBr 2 trigonal bipyramidal distorted square based pyramidal (TBDSBP) geometry around copper(II) metal centers. These two complexes exhibit significant SOD activity being the superior catalysts. Two new copper(II) complexes of the type [Cu(L)X 2), where L = (E)-N-phenyl-2-[phenyl (pyridine-2-yl)methylene]hydrazinecarboxamide X = Cl/Br have been synthesized and characterized by elemental analyses, FAB (fast atomic bombardment) magnetic measurements, electronic absorption, conductivity measurements cyclic voltammetry (CV) and Electron paramagnetic resonance (epr) spectroscopy. The structures of these complexes determined by single crystal X-ray crystallography show a distorted square based pyramidal (DSBP) geometry around copper(II) metal center. The distorted CuN 2OX (X = Cl/Br) basal plane in them is comprised of two nitrogen and one oxygen atoms of the meridionally coordinated ligand and a chloride or bromide ion and axial position is occupied by other halide ion. The epr spectra of these complexes in frozen solutions of DMSO showed a signal at g ca. 2. The trend in g-value ( g || > g ⊥ > 2.00) suggest that the unpaired electron on copper(II) has d x 2 - y 2 character. Biological activities in terms of superoxide dismutase (SOD) and antimicrobial properties of copper(II) complexes have also been measured. The superoxide dismutase activity reveals that these two complexes catalyze the fast disproportionation of superoxide in DMSO solution.