Speciation study of an imidazolate-bridged copper(II)-zinc(II) complex in aqueous solution
I Szilágyi1, I Labádi, K Hernadi
1Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged H-6720, Hungary.
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.
Related Concept Videos
Formation of Complex Ions
Valence Bond Theory
Ladder Diagrams: Complexation Equilibria
The formation constant, K1, for the formation of Cd(NH3)2+ complex from cadmium and ammonia is 3.55 × 102. Log K1 (i.e. pNH3) is 2.55, and...
Complexation Equilibria: Overview
The equilibrium constant of the complexation reaction is represented as the formation constant...
EDTA: Auxiliary Complexing Reagents
Extraction: Advanced Methods


