Fe-III was found to be gradually reduced by indole-3-acetic acid (IAA) in s
lightly acidic nitrate solution with further reoxidation of the resulting F
e-II upon drying in air, which is reasoned to be of ecological significance
considering IAA excretion by many soil micro-organisms. Fe-III-IAA complex
was isolated; its composition. some physicochemical properties and structu
ral aspects were studied using Mossbauer, FTIR spectroscopic and other tech
niques. Possible influence of Fe-III coordination on the redox properties o
f the ligand is also considered from the viewpoint of the nature of the bon
ding system which involves the conjugated pi -electronic system of the pyrr
ole cycle along with the carboxylic O-donor atom. (C) 2001 Elsevier Science
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