title: Speciation study of an imidazolate-bridged copper(II)-zinc(II) complex in aqueous solution.
abstract: The solution equilibrium and the binding mode of the species in the five-component system containing two metal ions (copper(II) and zinc(II)) and three ligands (A=diethylenetriamine, B=imidazole, C=tris(2-aminoethyl)amine) were investigated by pH-potentiometric titration, UV-visible spectrophotometry and EPR (electron paramagnetic resonance) spectroscopic titration in aqueous solution in the 2-11 pH range. An imidazolate-bridged heterobinuclear complex (ACuBH(-1)ZnC) was found to evolve above pH=7 and was stable between pH 7 and 11. The existence of the ACuBH(-1)ZnC complex (by determination of its molecular weight) was proved by mass spectrometry (ESI-MS (electrospray ionization mass spectrometry) and MALDI (matrix-assisted laser desorption/ionization) techniques). The electrochemical behaviour and the superoxide dismutase activity of this complex were also tested by cyclic voltammetry and the Riboflavin/NBT (nitro blue tetrazolium) assay, respectively.
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged H-6720, Hungary.
authors.forename: I
authors.initials: I
authors.lastname: Szilágyi
authors.forename: I
authors.initials: I
authors.lastname: Labádi
authors.forename: K
authors.initials: K
authors.lastname: Hernadi
authors.forename: I
authors.initials: I
authors.lastname: Pálinkó
authors.forename: N V
authors.initials: NV
authors.lastname: Nagy
authors.forename: L
authors.initials: L
authors.lastname: Korecz
authors.forename: A
authors.initials: A
authors.lastname: Rockenbauer
authors.forename: Z
authors.initials: Z
authors.lastname: Kele
authors.forename: T
authors.initials: T
authors.lastname: Kiss
mesh_terms: D001665:Binding Sites; D003300:Copper / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D011199:Potentiometry; D012996:Solutions / Q000737:chemistry; D013057:Spectrum Analysis; D013482:Superoxide Dismutase / Q000737:chemistry / Q000378:metabolism; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D007093:Imidazoles; D008024:Ligands; D012996:Solutions; D017967:Zinc Compounds; D003300:Copper; D013482:Superoxide Dismutase