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Updated: Jul 11, 2026
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Atomic Layer Deposition of Vanadium Dioxide and a Temperature-dependent Optical Model
Published on: May 23, 2018
Speciation in the vanadate-alanylhistidine-peroxide system
H Schmidt1, I Andersson, D Rehder
1Department of Chemistry, Umeå University, Sweden.
Journal of Inorganic Biochemistry
|July 8, 2000
Summary
This study determined the speciation of vanadium complexes with L-alpha-alanyl-L-histidine and hydrogen peroxide. The main quaternary complexes, VX2Ah2- and VX2Ah-, dominate in the pH range of 5 to 9.
Area of Science:
- Inorganic Chemistry
- Analytical Chemistry
- Coordination Chemistry
Background:
- Vanadium speciation is crucial for understanding its biological and environmental roles.
- The interaction of vanadium with organic ligands and peroxide is complex and requires detailed investigation.
- L-alpha-alanyl-L-histidine (Ah) is a biologically relevant dipeptide that can chelate metal ions.
Purpose of the Study:
- To elucidate the speciation of vanadium in the quaternary system involving H+, H2VO4(-), H2O2, and L-alpha-alanyl-L-histidine (Ah).
- To identify and characterize the vanadium complexes formed under specific conditions.
- To determine the formation constants and equilibrium conditions of these complexes.
Main Methods:
- Quantitative 51V NMR spectroscopy was employed to identify and quantify vanadium species.
- Potentiometric titrations using a glass electrode provided complementary data.
- The LAKE computer program was utilized to analyze combined NMR and potentiometric data.
Main Results:
- Two ternary complexes, (H+)p(H2VO4-)q(Ah)r with (p, q, r) values (0, 1, 1) and (1, 1, 1), were identified in the H+-H2VO4(-)-Ah system.
- Seven quaternary complexes were determined in the H+-H2VO4(-)-H2O2-Ah system, including four with a V/peroxo ligand/Ah ratio of 1:1:1 and three with a 1:2:1 ratio.
- The complexes VX2Ah2- and VX2Ah- were identified as the predominant quaternary species, with a pKa of 8.26, and are most abundant between pH 5 and 9.
Conclusions:
- The study successfully characterized the complex speciation of vanadium in the quaternary system.
- The identified complexes and their formation constants provide valuable insights into vanadium chemistry.
- Distribution diagrams illustrate the equilibrium conditions, aiding in the understanding of vanadium behavior in similar environments.
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