SOLUTION CHEMISTRY OF VANADIUM(IV) AND VANADIUM(V) WITH THE BIDENTATELIGAND 1,2-DIMETHYL-3-HYDROXY-4(1H)-PYRIDINONE - RELEVANCE TO THE TREATMENT OF DIABETES

1,2-Dimethyl-3-hydroxy-4(1H)-pyridinone (HL) forms an unusually wide r ange of oxo, hydroxy and non-oxo complexes with vanadium(IV) and vanad ium(V) in aqueous solution; the tris non-oxo vanadium(IV) complex [V(I V)L(3)](+) is the first such monocationic complex to be studied in aqu eous solution and the monocationic tris hydroxyvanadium(V) complex [V- V(OH)L(3)](+) is the first such species to be reported; the neutral hi s complex [V-V(O)(OH)L(2)] is of physiological significance in the tre atment of diabetes.