Related Experiment Video
Updated: Jun 22, 2026

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
Stability of binary and ternary copper(II) complexes with 1,10-phenanthroline, 2,2'-bipyridyl and some alpha-amino
1Department of Chemistry, Faculty of Arts and Sciences, Uludağ University. nturkel@uludag.edu.tr
Abstract:
Interactions of certain amino acids with some metal ions have significant consequences in biological systems. Metal ions can act as co-factors in the regulation of enzymatic reactions. Interactions of metal ions with amino acid side chains or with different organic complexes is also essential for many biological events. In this study, the stability constants of 1 : 1 : 1 ternary complexes of Cu(II) with 1,10-phenanthroline (Phen) as the primary ligand, and 2,2'-bipyridyl (Bpy) and some selected alpha-amino acids [(glycine (Gly), leucine (Leu), glutamine (Gln)] as secondary ligands, were identified in I=0.1 M ionic medium at t=(25+/-0.1) degrees C in aqueous solutions, by potentiometry. The protonation constants of the free ligands and the stability constants of the binary and ternary systems were also determined under the same experimental conditions. The protonation constants of all of the ligands and the stability constants of the formed complexes were evaluated by using the BEST computer program. The stabilities of the ternary complexes have been quantitatively compared with those of the corresponding binary complexes in terms of the some parameters. The concentration distributions of the complexes in solution were also evaluated. Species distributions as a function of pH reveal that the MAB ternary complexes predominate over a pH range, where M=Cu(II); A=Phen; B=Bpy, Gly, Leu and Gln.
More Related Videos
11:38Quantifying the Binding Interactions Between Cu(II) and Peptide Residues in the Presence and Absence of Chromophores
Published on: April 5, 2022
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
Related Concept Videos
Complexation Equilibria: Factors Influencing Stability of Complexes
Complexation Equilibria: The Chelate Effect
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
Complexometric Titration: Ligands
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...
Extraction: Advanced Methods