Siderophore chemistry of vanadium. Kinetics and equilibrium of interaction between vanadium(IV) and desferrioxamine B in aqueous acidic solutions

The kinetics and equilibrium of interaction between vanadyl sulfate and a natural trihydroxamate-based siderophore, desferrioxamine B methanesulfonate, were studied spectrophotometrically in acidic aqueous perchlorate solutions of 2.0 M ionic strength. The bi-, tetra-, and hexadentate-bonded complexes were formed under these conditions, and their stability constants were calculated. The rate constants for the formation and hydrolysis of the bi- and tetradentate complexes were estimated. The formation of the bidentate complex proceeds via two parallel pathways involving the hydrolyzed and unhydrolyzed vanadyl-aquo species. The hydrolyzed form was found to react with the siderophore ca. 10⁵ times faster than the unhydrolyzed form. © 1991 American Chemical Society.

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Author Ines Batinic-Haberle Radiation Oncology