Redox behavior of aliphatic hydroxamic acid and its iron(III) complexes

N-Hydroxydodecanamide (HA12) and its trihydroxamato-iron(III) complex (HA12Fe3) have been synthesized and characterized by various methods including structural determination by single crystal X-ray diffraction and cyclic voltammetry (CV). In order to complete our previous CV study on HA12 and its complexes, our aim was to investigate the variation in redox potential upon changes in concentration and pH. The redox couples previously observed with HA12 and HA12Fe3 at 100 µM shifts towards less positive values when the concentration or pH of the solution increases. These results indicate that oxidation is easier when concentrations are higher and in basic media. The slopes of -0.06 V/pH (in agreement with the theoretical data) and -0.077 V/pH (slightly higher than the theoretical slope) were observed for HA12 and HA12Fe3, respectively. This observation would explain the slower oxidation of HA12Fe3 than HA12.