Related Experiment Video
Updated: Jun 8, 2026
05:59
Green Synthesis of Quinoline-Based Ionic Liquid
Published on: September 27, 2024
Hydroxyquinoline based binders: promising ligands for chelatotherapy?
Ana Budimir1, Nicholas Humbert, Mourad Elhabiri
1Laboratoire de Physico-Chimie Bioinorganique, UMR 7177 du CNRS, Université Louis Pasteur, Strasbourg, France. anab@pharma.hr
Journal of Inorganic Biochemistry
|October 8, 2010
Summary
Clioquinol, a neurological drug for Alzheimer's disease, effectively binds to metal ions like copper. This study details its coordination properties with biologically relevant divalent metals, crucial for understanding its therapeutic potential.
Area of Science:
- Coordination chemistry
- Neuropharmacology
- Biophysical chemistry
Background:
- Alzheimer's disease is a neurodegenerative disorder.
- Metal ion dyshomeostasis is implicated in Alzheimer's pathogenesis.
- Clioquinol is an oxine-type drug investigated for neurological conditions.
Purpose of the Study:
- To investigate the coordination properties of clioquinol with biologically relevant divalent metal ions.
- To characterize the metal-clioquinol species formed.
- To determine the stability of these complexes.
Main Methods:
- Electrospray mass spectrometry (ESI-MS)
- Absorption spectrophotometry
- Potentiometry
Main Results:
- Clioquinol forms both mono- and bis-chelated species with Cu, Zn, Ni, Co, and Mn.
- Stability constants were determined for the complexes.
- Cupric (Cu2+) complexes exhibited the highest stability among the studied metal ions.
Conclusions:
- The coordination behavior of clioquinol with divalent metal ions was elucidated.
- The high stability of copper-clioquinol complexes is significant.
- Findings contribute to understanding clioquinol's mechanism in Alzheimer's disease therapy.
Related Concept Videos
01:19Complexation Equilibria: The Chelate Effect
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
00:43Complexometric Titration: Ligands
Different monodentate and polydentate ligands are used as complexing agents in complexometric titration reactions. The formation of complexes by mono- and bidentate ligands involves two or more intermediate steps, limiting their use as complexing agents. In comparison, polydentate ligands can form complexes with metal ions in a single-step process, facilitating sharper end points. This means polydentate ligands, such as amino carboxylic acid derivatives, are most commonly employed in...
00:56Extraction: Advanced Methods
Metal ions can be separated from one another by complexation with organic ligands–the chelating agent– to form uncharged chelates. Here, the chelating agent must contain hydrophobic groups and behave as a weak acid, losing a proton to bind with the metal. Since most organic ligands used in this process are insoluble or undergo oxidation in the aqueous phase, the chelating agent is initially added to the organic phase and extracted into the aqueous phase. The metal-ligand complex is formed in...
01:22EDTA: Chemistry and Properties
Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...
02:51Metal-Ligand Bonds
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
01:26EDTA: Auxiliary Complexing Reagents
EDTA titrations are usually carried out in highly basic conditions, where the fully deprotonated form of EDTA, Y4−, actively complexes with the free metal ions in the solution. Several metal ions precipitate as hydrous oxide (hydroxides, oxides, or oxyhydroxides) under these conditions, lowering the concentration of free metal ions in the solution. For this reason, auxiliary complexing agents or ligands such as ammonia, tartrate, citrate, or triethanolamine are used in EDTA titrations to...