Change search
ReferencesLink to record
Permanent link

Direct link
Speciation in peroxovanadate systems
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
2003 (English)In: Coordination Chemistry Reviews, Vol. 237, no 1-2, 77-87 p.Article in journal (Refereed) Published
Abstract [en]

Detailed and thorough potentiometric and 51V-NMR spectroscopic investigations of H+–H2VO4−–H2O2–Ligand systems have been performed at 25 °C in 0.15 M Na(Cl) ionic medium. Extensive ranges of vanadate, hydrogen peroxide and ligand concentration and of pH have been covered. The medium was chosen to represent the physiological conditions in human blood. The computer program , designed to treat different types of data simultaneously, has been used to establish the entire speciation in the systems. Before studying systems containing the ligand (L), the complete speciation in the subsystem H+–H2VO4−–H2O2 must be known under the same experimental conditions. The formation constants in this subsystem have earlier been determined and it was found that hydrogen peroxide interacts with vanadate in the whole pH range studied (0.5–10.5). In all, 10 peroxovanadate species were identified and diperoxovanadate species were found to be exceptionally stable at physiological pH. The ligands studied so far include imidazole (Im), -α-alanyl--histidine (Ah), -α-alanyl--serine (As), picolinic acid (Pi), and -(+)-lactic acid (La). In these five systems, as many as 3, 8, 6, 8, and 5 different peroxovanadate—L species (isomers included) were identified. A feature common to all these systems is that V(H2O2)2L species are formed at physiological pH. Notably, the 51V chemical shift values of diperoxovanadate moieties are always found in the range −670 to −770 ppm, and those of monoperoxovanadate from −540 to −670 ppm. The equilibrium conditions are illustrated in distribution diagrams and the effectiveness of the different ligands as complexation agents are compared. In the case of diperoxovanadate complexes, ligands with aromatic nitrogen (Im, Pi, Ah) are the most effective, the one with both aliphatic nitrogen and oxygen (As) is less effective, and the one with oxygen only (La) is the least preferred.

Place, publisher, year, edition, pages
2003. Vol. 237, no 1-2, 77-87 p.
Keyword [en]
Potentiometry, 51V-NMR, Speciation, Bioinorganic chemistry, Insulin-mimetic activity, Peroxovanadate complexes
URN: urn:nbn:se:umu:diva-9294DOI: 10.1016/S0010-8545(02)00223-0OAI: diva2:148965
Available from: 2008-03-18 Created: 2008-03-18 Last updated: 2013-02-14Bibliographically approved
In thesis
1. Vanadate and Peroxovanadate Complexes of Biomedical Relevance: A speciation approach with focus on diabetes
Open this publication in new window or tab >>Vanadate and Peroxovanadate Complexes of Biomedical Relevance: A speciation approach with focus on diabetes
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Diabetes mellitus is one of the most threatening epidemics of modern times with rapidly increasing incidence. Vanadium and peroxovanadium compounds have been shown to exert insulin–like actions and, in contrast to insulin, are orally applicable. However, problems with side–effects and toxicity remain. The exact mechanism(s) by which these compounds act are not yet fully known. Thus, a better understanding of the aqueous chemistry of vanadates and peroxovanadates in the presence of various (bio)ligands is needed.

The present thesis summarises six papers dealing mainly with aqueous speciation in different vanadate – and peroxovanadate – ligand systems of biological and medical relevance. Altogether, five ligands have been studied, including important blood constituents (lactate, citrate and phosphate), a potential drug candidate (picolinic acid), and a dipeptide (alanyl serine) to model the interaction of (peroxo)vanadate in the active site of enzymes. Since all five ligands have been studied both with vanadates and peroxovanadates, the number of systems described in the present work is eleven, including the vanadate – citrate – lactate mixed ligand system. The pH–independent formation constants have been determined for 33 ternary vanadate – ligand, 41 quaternary peroxovanadate – ligand and two vanadate – mixed ligand species in addition to the pKa values of all five ligands. These constants have been used to model physiological conditions, and the biomedical relevance of the different species is discussed.

The studies have been performed at 25 ºC in the physiological medium of 0.150 M Na(Cl), i.e. the ionic strength of human blood. No buffers have been used, and wide pH–ranges have usually been covered. The applied experimental techniques comprise mostly 51V NMR and potentiometry, but 31P, 13C, 1H and 14N NMR as well as EPR and ESI–MS have also been used to gain additional information. Multimethod data have been treated by the least–squares program LAKE and modelling has been carried out by the software package WinSGW.

Whenever possible, solution structures of the species have been proposed. In addition, simple biological tests have been carried out to determine the stability of the formed peroxovanadate complexes in the presence of human catalase. A brief comparison is given of the different vanadate – ligand and peroxovanadate – ligand systems with emphasis on observed trends and general features.

Place, publisher, year, edition, pages
Umeå: Kemi, 2005. 74 p.
Inorganic chemistry, vanadium, hydrogen peroxide, lactate, citrate, phosphate, alanyl serine, picolinic acid, speciation, formation constants, equilibrium, solution structure, potentiometry, NMR (51V, 31P, 13C, 1H), Oorganisk kemi
National Category
Inorganic Chemistry
Research subject
Inorganic Chemistry
urn:nbn:se:umu:diva-489 (URN)91-7305-854-8 (ISBN)
Public defence
2005-04-22, KB3A9, KBC-huset, Umeå Universitet, Umeå, 13:00
Available from: 2005-03-31 Created: 2005-03-31 Last updated: 2012-06-26Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Pettersson, LageAndersson, IngegärdGorzsás, András
By organisation
Department of Chemistry

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 33 hits
ReferencesLink to record
Permanent link

Direct link