THE FORMATION OF TERNARY COMPLEXES BETWEEN VO(MALTOLATE)(2) AND SMALLBIOLIGANDS

In order to assess the solution state of VO(IV) in organisms when admi nistered in the form of the bis(maltolato) complex (VO(malt)(2)), tern ary systems of VO (IV)-maltol with various bioligands (potential metal ion binders of biofluids and tissues), such as inorganic phosphates, adenosine nucleotides, catechol derivatives, citrate and oxalate, were studied. The speciation of VO(IV) in these ternary systems was studie d by pH-potentiometry, while the binding modes of the complexes were d etermined by spectral (UV-Vis and electron paramagnetic resonance) met hods. The results support strongly the assumption that VO(malt), under goes transformation into mixed ligand complexes formed with the variou s VO(IV) binders of biological fluids and tissues. (C) 1998 Elsevier S cience S.A. All rights reserved.