Reactions of ligated Fe(III) complexes with nitrite

CHED 853

Christopher E. Carrig and Stephen K. O'Shea.
The concentration of nitrite ion has risen in the aquatic environment due to the increased application of nitrate and ammonium agricultural fertilizers. Nitrite ion has contaminated household drinking water in a number of communities to toxic levels. Excess nitrite ion in the blood can cause the medical condition methemoglobinemia. This research investigated the formation of Fe (II) nitrosyl adduct as a model of the less studied "free" or non-protein-bound iron in biological fluids. The rate of reaction of nitrite ion with varying precomplexed iron (III) center in the presence of triphenylphosphine was followed in situ by uv/vis spectroscopy. The series of nitrogen based ligands used were cyclam, pentamine, tetramine, triamine diamine and dipyridyl. This research shows a relationship between the ease of reduction of the ligated Fe (III) and the pseudo first order kinetics for the formation the iron (II) nitrosyl adduct.