Mechanistic studies on the activation of NO by iron and cobalt complexes

In this review, the reactions of nitric oxide with selected Fe and Co complexes of biological and environmental importance are reviewed. Fundamental chemical kinetics and mechanisms of reactions that lead to the formation and decay of nitrosyl complexes are illustrated and discussed on the basis of studies on Fe-II chelates, Fe-II/III pentacyano complexes, Fe-III porphyrins, cytochrome P450 and model complexes, Co-II/III porphyrins and vitamin B-12. Throughout the review, the focus is on mechanistic details of the binding of NO to and the release of NO from metal complexes and on the nature of the stable metal-NO complexes produced in solution. As will be seen for most of the presented reactions, the interaction of NO with the metal complex involves activation of the small NO molecule so that charge transfer occurs as a result of the formation of the metal-NO bond. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)