Oxygen Atom Transfer (OAT) Reactions Performed by Synthetic Nonheme Oxoiron(IV) Species Supported by Tetraaza-Macrocyclic Ligands.

Abstract

Non-heme iron enzymes are of great importance in harvesting O2 to carry out versatile oxidation reactions such as the hydroxylation of aliphatic and aromatic substrates, olefin epoxidation, alkane halogenation and other vital biological transformations. The reactive oxoiron(IV) intermediate found in these non-heme iron enzymes has been synthesized separately in the absence of the enzyme active site and shown to mimic the enzymatic transformations. The focus of such applications relies heavily on the ability of these reactive oxoiron(IV) species to abstract H-atoms from organic substrates, despite the fact that enzymes typically perform two-electron oxidations of the substrates, such as oxygen atom transfer (OAT) reactions.This thesis explores three types of OAT reactions performed by different synthetic non-heme oxoiron(IV) complexes. It first complexes, demonstrating the different behaviors of the oxoiron(IV) moiety. Chapter 2 focuses on the exchange of the Fe(IV)=O moiety with water in non-heme systems as compared to their heme analogs. More importantly, Chapter 3 elucidates the general mechanism for the hydroxylation of a pendant aromatic ring by an oxoiron(IV) species to provide a complete reaction scheme. Lastly, Chapter 4 examines the ligand effects on perturbing the ability of an oxoiron(IV) species to transfer its oxygen atom, with the unexpected discovery of an FeIII-OH species performing disproportionation reactions.