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Oxidation kinetics of the potent insulin mimetic agent bis(maltolato)oxovanadium(IV) (BMOV) in water and in methanol

TitleOxidation kinetics of the potent insulin mimetic agent bis(maltolato)oxovanadium(IV) (BMOV) in water and in methanol
Publication TypeJournal Article
Year of Publication1996
AuthorsSun, Y, James, BR, Rettig, SJ, Orvig, C
JournalInorganic Chemistry
Volume35
Pagination1667-1673
Date PublishedMar
Type of ArticleArticle
ISBN Number0020-1669
KeywordsANATION, AQUEOUS-SOLUTION, COMPLEXES, CYSTEINE, KINASE, RAT ADIPOCYTES, VANADYL TREATMENT
Abstract

{The kinetics of oxidation of bis(maltolato)oxovanadium(IV), BMOV or VO(ma)(2), by dioxygen have been studied by UV-vis spectroscopy in both MeOH and H2O media. The VO(ma)(2):O-2 stoichiometry was 4:1. In aqueous solution, the pH-dependeut rate of the VO(ma)(2)/O-2 reaction to generate cis-[VO2(ma)(2)](-) is attributed to the deprotonation of coordinated H2O, the deprotonated species [VO(ma)(2)(OH)](-) being more easily oxidized (k(OH) = 0.39 M(-1) s(-1), 25 degrees C) than the neutral form VO(ma)(2)(H2O) (k(H2O) = 0.08 M(-1) s(-1), 25 degrees C). The activation parameters for the two second-order reactions in aqueous solution were deduced from variable temperature kinetic measurements. In MeOH, VO(ma)(2) was oxidized by dioxygen to cis-VO(OMe)(ma)(2), whose structure was characterized by single-crystal X-ray diffraction; the crystals were monoclinic, C2/c, with a = 28.103(1) Angstrom

URL<Go to ISI>://A1996UA16900042