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Updated: Jun 28, 2026
05:21
The Effect of Ultraviolet Radiation on the Chemical Bath Deposition of Bis(thiourea) Cadmium Chloride Crystals and the Subsequent CdS Obtention
Published on: August 30, 2018
Convolution-deconvolution cyclic voltammetric equilibria study on cadmium(II)-L-histidinate in aqueous solutions
R Abdel-Hamid1, M K Rabia, A B El-Nady
1Department of Chemistry, Faculty of Science, Sohag, Egypt.
Talanta
|September 1, 1994
Summary
This study investigated cadmium(II)-L-histidinate complexation using cyclic voltammetry. Different pH conditions revealed distinct binary and ternary cadmium-histidine complexes, with stability constants computed.
Area of Science:
- Coordination Chemistry
- Electrochemistry
- Analytical Chemistry
Background:
- L-histidine is a biologically relevant amino acid.
- Cadmium(II) is a toxic heavy metal with known complexation behavior.
- Understanding metal-ligand interactions is crucial in environmental and biological systems.
Purpose of the Study:
- To investigate the complexation of cadmium(II) with L-histidinate in aqueous solution.
- To determine the speciation and stability of cadmium-histidine complexes at different pH values.
- To elucidate the structure of the formed complexes based on histidine's ligating sites.
Main Methods:
- Cyclic voltammetry was used to study the electrochemical behavior of cadmium(II) and its complexes.
- The POLAG computer program processed the voltammetric data for analysis.
- Experiments were conducted in 0.1 mol/dm(3) NaClO(4) aqueous solution at 298K and varying pH.
Main Results:
- Cadmium(II) reduction and its complexes showed reversible, diffusion-controlled, two-electron waves across the pH range.
- At pH 6.73-7.44, the system involved binary complexes ([Cd(HisO.H)], [Cd(HisO.H(2))(2)]) and a ternary complex ([Cd(HisO.H)(HisO.H(2))]).
- At pH 8.53-8.92, the dominant species were binary complexes ([Cd(HisO)(2)]) and cadmium hydroxide ([Cd(OH)]).
Conclusions:
- The speciation of cadmium(II)-L-histidinate complexes is highly pH-dependent.
- Overall stability constants for the identified complexes were successfully computed.
- The study provides insights into the structural aspects of cadmium-histidine complexes based on histidine's coordination.
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