The synthesis, characterization and reactivity of oxidized and reduced heme/non-heme diiron complexes

Chapter 1 serves as an introduction to enzymatic systems employing nitric oxide redox chemistry, specifically nitrite reductases and nitric oxide reductase. Synthetic iron and copper coordination complexes and their interactions with nitrogen oxide (NOx) substrates are examined.; Chapter 2 is the resonance Raman investigation of [(5L)Fe III-O-FeIII-Cl]+, with characterization of the asymmetric Fe-O-Fe vibration of the mu-oxo heme/non-heme diiron unit. Spectroscopic data from the model complex is directly related to similar findings for the enzyme nitric oxide reductase (NOR), suggesting that the biological system contains a heme/non-heme diiron mu-oxo moiety.; Chapter 3 discusses the synthesis of [(6L)FeIII -O-FeIII-Cl]+ and related complexes, along with their characterization by UV-Visible, resonance Raman, Mossbauer, and NMR spectroscopies. This data is further complemented by SQUID magnetic susceptibility measurements and the structure has been elucidated by X-ray crystallography. These compounds are structural and spectroscopic models for the oxidized active site in the enzyme nitric oxide reductase.; Chapter 4 presents the synthesis of the corresponding reduced complex [(6L)FeII...FeII-Cl] +, which has been characterized by UV-Visible, NMR, and resonance Raman spectroscopies. We further discuss the reactivity of the reduced complex with dioxygen, carbon monoxide, and nitric oxide. The relevance to these systems to bacterial nitric oxide reductase is discussed.; Chapter 5 describes the photochemistry of [(6L)Fe III-O-FeIII-Cl]+. Laser or lamp photolysis of [(6L)FeIII-O-FeIII-Cl] + results in the clean formation of [(6L)Fe II...FeII-Cl]+ with subsequent oxidation of solvent or substrates. The use of chlorinated aromatic solvents for this reaction results in the isolation of a (P)FeIII-Cl species with concomitant solvent dehalogenation.