EPR AND NMR-STUDIES OF FE(I)-NO COMPLEXES AND THEIR RELEVANCE IN BIOLOGICAL AND ENVIRONMENTAL PROCESSES

Nitric oxide is implicated in a wide range of biological functions and in many processes of ecological importance. The formation of iron-nit rosyl complexes is fairly well documented, although the oxidation stat e of the iron atom is not adequately elucidated: the metal ion is in t he formal+1 oxidation state forming low-and high-spin d(7) complexes. Owing to the documented evidence that iron-NO compounds are involved i n bioregulatory mechanisms and immune responses, and to the biological relevance of these processes and of related structures, the EPR and N MR features of these complexes were reconsidered and combined EPR and NMR analysis was carried out to obtain information on binding sites an d coordination behaviour. (C) 1997 John Wiley & Sons, Ltd.