ABSTRACT
Two copper(II) complexes [CuL(1)Cl]ClO(4) and [CuL(2)MeCN](ClO(4))(2)xH(2)O were synthesized (L(1)= 1-(benzimidazole-2-ylmethyl)-1,4,7-triazacyclononane, L(2)= 1,4-bis(benzimidazole-2-ylmethyl)-1,4,7-triazacyclonone). The benzimidazole groups were N-substituents of tacn, and the complexes are more stable than their parents. They are able to catalyse the dismutation of superoxide anion in aqueous solutions at physiological pH and in bovine serum albumin solution (0.5 mg ml(-1)). X-ray structure analysis and EPR and electronic spectra show that the structure of complex is more similar to the Cu(II) centre of Cu(2)Zn(2)SOD than that. Comparing with other Cu(II) complexes, the complex possesses both high SOD activity and highly thermodynamic stability.
Subject(s)
Benzimidazoles/chemistry , Biomimetic Materials/chemistry , Copper/chemistry , Heterocyclic Compounds/chemistry , Molecular Mimicry , Superoxide Dismutase/chemistry , Superoxide Dismutase/metabolism , Biomimetic Materials/metabolism , Catalysis , Crystallography, X-Ray , Electrochemistry , Electron Spin Resonance Spectroscopy , Enzyme Stability , Hydrogen-Ion Concentration , Molecular Structure , Serum Albumin, Bovine/chemistry , Solutions/chemistry , Superoxides/metabolism , Thermodynamics , TitrimetryABSTRACT
The electrochemical behavior of Cu(2)Zn(2)SOD on mercury electrodes was studied by controlled potential electrolysis. By comparison of UV, Raman spectra and activity of Cu(2)Zn(2)SOD before electrochemical reduction and after re-oxidation, it is proved that the conformation and activity are not changed.
Subject(s)
Electrolysis/methods , Erythrocytes/enzymology , Mercury/chemistry , Spectrum Analysis, Raman/methods , Superoxide Dismutase/metabolism , Animals , Cattle , Copper/chemistry , Electrodes , Oxidation-Reduction , Potentiometry , Superoxide Dismutase/chemistry , Zinc/chemistryABSTRACT
Four heterodinuclear cryptates [EuML(dmf)](ClO(4))(2) (M=Ca, Cd, Ni, Zn) were synthesized by a two-step method (L denotes deprotonated anionic cryptand synthesized by condensation of tris(2-aminoethyl)amine with 2,6-diformyl-4-chlorophenol). The ES-MS spectra of the four cryptates and the crystal structure of [EuNiL(dmf)](ClO(4))(2) x MeCN confirm that a strict dinuclear Eu(III)-M(II) entity exits in the cryptates. The cyclic voltammetry and luminescence spectral investigations indicate that the introduction of second metal ions into the mononuclear Eu(III) cryptate result in a negative shift of the redox potential of Eu(III) and a change in luminescence intensity of Eu(III). The cryptate [EuML(dmf)](ClO(4))(2) was shown to quench the emission of Eu(III) when M=Ni and to enhance the emission of Eu(III) when M=Ca, Cd, and Zn in the sequence: mononuclearSubject(s)
Europium/chemistry
, Luminescent Measurements
, Metals/chemistry
, Molecular Structure
, Spectrometry, Mass, Electrospray Ionization
