P450 enzyme models carrying a SO3- ligand coordinating to iron have been synthesized and characterized. These complexes show characteristics very similar to those of iron-heme cofactors of P450 enzymes. Their reactivity towards different reactions catalyzed by P450 enzymes such as epoxidation of double bonds, hydroxylation of non-activated C-H bonds, N-dealkylation of amines, and cleavage of diols (C-C-bond cleavage) has been investigated. (c) 2005 Elsevier Inc. All rights reserved.