Water and time dependent interaction of iron(III) with indole-3-acetic acid

The influence of water on the interaction between iron(III) and indole-3-acetic acid (IAA) was studied in different organic solutions using rapid-scan stoppedflow spectrophotometry and rapid-freeze/quench Mössbauer spectroscopy. Measurements were also performed in ethanol– water and acetone–water mixtures. The results showed that the interaction between Fe and IAA resulted in dimeric Fe–IAA complex within 1 s, followed by a slow second step to give Fe and IAA(oxidized). No such products were formed in the absence of water. The visible and Mössbauer spectra reflect the nature of the organic solvent and that of the anion of iron(III) salts.