Synthesis and structural studies of new polyhydroxamic iron(III) complexes for the use in nuclear magnetic resonance imaging. Part II: Study of the complexes formed in situ from hydroxamic acids

Numerous analogous dihydroxamates of rhodotorulic acid have been prepared, and their mode of complexation of iron(III) and the stability of these complexes studied as a function of pH, for comparison wimh ferrioxamine B and the complex of acetohydroxamic acid with iron(III). This study has shown that the stoichiometry of the complexes is 2:3 (at a pH of 7) and 1:1 (at a pH of 2), and that, in spite of a complete complexation, their electrochemical behaviour varies greatly with pH. The very strong complexation constant observed (log β110 = 21.3) at a pH of 1 with the ligand N,N'-bis(acetylhydroxamino-3' propyl)-pentyloxy-4 pyridine-2,6-dicarboxamide confirms the strong complexation capacity of iron(III) by these complexes. The high relaxivity of the complex of iron(III) with the N,N'-bis(acetylhydroxyamino-3'-propyl)-(amino-4''-butyloxy)-4-pyridine -2,6-dicarboxamide suggests that this product could be a useful contrasting agent for nuclear magnetic imaging.

Duke Scholars

Author Alvin L. Crumbliss Chemistry