Magnetic properties of a diferrous-water complex and ligands for modeling the active site of MMOH

Abstract

Chapter 1: The Importance of Modeling Diiron Sites in Nature.There are a variety of metalloenzymes that have nearly identical carboxylate-bridged diiron active sites. An example is sMMOH, an enzyme that catalyzes the conversion of methane to methanol. A detailed description of the active site of sMMOH[red] is given and attempts at reproducing its structure in a model complex are discussed. Chapter 2: A Diiron(II) Diaqua Complex: Modeling Water in the Active Site of sMMOH[red]. There are water molecules in the first and second coordination spheres of the diiron centers in sMMOH[red]. A carboxylate-bridged diferrous complex, [Fe₂...(THF)₂], was synthesized to incorporate the presence of water in a model complex and to investigate the function(s) of these water molecules. The synthesis, structural characterization and magnetic properties of this complex are presented. Chapter 3: Ligands for Modeling the Syn Disposition of Nitrogen Atoms in the Active Site of MMOH. The active sites of a variety of carboxylate-bridged diiron metalloenzymes are very similar and feature the syn disposition of two histidine ligands with respect to the iron-iron vector. This orientation has not yet been modeled in a diiron complex with four carboxylate ligands and a stable yet flexible platform. Such geometry may be necessary to replicate the functions of these enzymes. The syntheses of ligands intended to enforce this syn disposition are described and directions for future ligand design are outlined.