Elsevier

Inorganica Chimica Acta

Volume 170, Issue 2, 17 April 1990, Pages 171-176
Inorganica Chimica Acta

Iron chelators of the pyridoxal isonicotinoyl hydrazone class Part II. Formation constants with iron(III) and iron(II)

https://doi.org/10.1016/S0020-1693(00)80472-7Get rights and content

Abstract

Formation constants for the iron(III) complexes of the orally effective iron chelator pyridoxal isonicotinoyl hydrazone (PIH) and three analogues: pyridoxal benzoyl hydrazone (PBH), 3-hydroxy- isonicotinaldehyde isonicotinoyl hydrazone (IIH) and salicylaldehyde isonicotinoyl hydrazone (SIH), have been determined by a combination of spectrophotometry and potentiometry. All four ligands bind iron(III) strongly giving, at physiological pH 7.4, values of pM (−log[uncomplexed metal]) between 27.7 and 50, comparable to or greater than those for transferrin (25.6) and desferrioxamine B (28.6). The complexation of Fe(II) by PIH has also been studied and has been found to be appreciable but very much weaker than that for Fe(III).

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    • The interaction of pyridoxal isonicotinoyl hydrazone (PIH) and salicylaldehyde isonicotinoyl hydrazone (SIH) with iron

      2018, Journal of Inorganic Biochemistry
      Citation Excerpt :

      Furthermore, favoring the assignment of the pKa value 4.4 to the ring N of the pyridoxine moiety, influences the calculation for the determination of pFe3 + values. The value resulting from this work ([Fe3 +]total = 10− 6 M, [PIH]total = 10− 5 M, pH 7.4) is 26.2, which is lower than the previously published value of 27.7 [26]. However, the previous workers adopted different conditions for pFe3 +, namely [Fe3 +]total = 10− 6 M, [PIH]total = 10− 3 M, pH 7.4.

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