Interaction of 2-amino-N-hydroxypropanamide with vanadium(V) in aqueous solution

Formation and structure in aqueous solution of complexes between vanadium(V) and aminohydroxamic acids that potentiates vanadium’s insulinomimetic activity: l-glutamic γ-hydroxamic and l-aspartic-β-hydroxamic acids

“…Since vanadium(V) ion does not exhibit any d-d transition in the visible spectrum, the color observed must be attributed to a strong oxygen to metal charge-transfer absorbance band in the ultraviolet [26,27] that extends into the visible range. This behavior was observed in our previous works about the vanadium(V) complexation by acetohydroxamic [11], b-alaninehydroxamic [13], glycinehydroxamic and a-aminohydroxamic acids [28]. In all these cases there is no consumption or release of protons, as observed now.…”

“…Comparing the values attributed to asp-b-ha and glu-c-ha with b-alaha [13] it becomes clear that the presence of the carboxylic group in asp-b-ha increases the acidity of both amino and hydroxamic acid group and decrease the acidity of the amino group of gluc-ha.…”

“…(1) was applied and the final set of mononuclear species and their formation constants that fit the potentiometric data reasonably well are shown in Table 1. This table also includes data of the vanadium (V)-b-alaninehydroxamic acid system [13].…”

“…In previous papers, we have demonstrated how combined potentiometric, spectrophotometric and 51 V NMR methods allowed the identification of several species and determination of their formation constants in aqueous solution containing vanadium(V) and acetohydroxamic acid [11,12] and b-alaninehydroxamic acid [13]. In both systems, at least two vanadium-ligand 0020-1693/$ -see front matter Ó 2010 Elsevier B.V. All rights reserved.…”

The Chemistry and Biochemistry of Vanadium and the Biological Activities Exerted by Vanadium Compounds

“…497,498 Speciation studies on alkylhydroxamic acid-vanadate complexes give log K f values on the order of 7-38 depending on the pH. 499,500 Cinnamoylhydroxamate was shown to form 1:1 and 1:2 complexes with V(V) at 1.8 M HCl in 2-methyl-4-pentanone; the stepwise formation constants were given and an octahedral coordination geometry was suggested. 501 The first structurally characterized V-hydroxamate complexes were the V(V)-complexes of benzohydroxamic acid (92), 502 the dihydroxamate N,N′-dihydroxy-N,N′-diisopropylheptanediamide, 502 and N-phenylbenzohydroxamic acid (93).…”