Structural study of the interaction of vanadate with the ligand 1,2-dimethyl-3-hydroxy-4-pyridinone (Hdmpp) in aqueous solution

• Type: Article in International Scientific Journal
• Date: 2000

Authors

Castro, MMCA (Author) Other; Geraldes, CFGC (Author) Other; Gameiro, P (Author) FCUP; Pereira, E (Author) FCUP; Castro, B (Author) FCUP; Rangel, M (Author) ICBAS

Journal

Title: Journal of Inorganic Biochemistry

Vol. 80

Pages: 177-179

ISSN: 0162-0134

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 29 Citations

Scopus - 29 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-001-01V

DOI: 10.1016/s0162-0134(00)00028-3

Abstract (EN): The interaction of vanadate with the ligand 1,2-dimethyl-3-hydroxy-4-pyridinone (Hdmpp) was studied in aqueous solution using a combination of multinuclear NMR and EPR spectroscopies, as well as potentiometry and cyclic voltammetry. The different species in solution were identified and characterized, and their pK(a) values and stability constants determined. The vanadium complexes formed in solution are strongly dependent on media composition (ionic strength, presence of buffer), pH and metal-to-ligand ratio (M:L). Two major species - V(V)/dmpp and V(V)/(dmpp)(2) - are formed in a 140 mM NaCl solution within the pH range 4.5 to 9.0, when M:L = 1:2. In the presence of excess ligand (M:L less than or equal to 1:5), only the 1:2 complex is present, and at pH < 4 paramagnetic species are detected by EPR in solution, thus indicating a reducing capacity of the ligand. Cyclic voltammetry shows that redox processes in solution are not just electron transfer, but are accompanied by chemical reactions. The pK(a) values and stability constants were determined both by V-51 NMR spectroscopy and potentiometry. The present results have a particular interest in the understanding of the aqueous solution chemistry in aerobic conditions of bis(1,2-dimethyl-3-hydroxy-4-pyridinonato) oxovanadium(IV) complex, VO(dmpp)(2), a vanadium compound with potential insulin-mimetic properties.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 3