| Chapter 1 deals with heme-based binuclear complexes containing iron-cyanide-copper bridges in three different oxidation states related to the heme-a 3/CuB site in cyanide-inhibited heme-copper oxidases. A series of assemblies containing the bridges FeIII-CN-Cu II, FeIII-NC-CuI, and FeII-NC-Cu I were prepared by reaction of [Fe(OEP)(Py)(CN)] and CuII/I precursors. These assemblies were characterized by X-ray crystallography and UV/vis and IR spectroscopy. Linkage isomerism, trends in νCN values, and relation to the enzymes are thoroughly discussed.; Chapter 2 provides the first systematic study of the electronic description of the electron transfer series [Ni(S2C2Me2) 2]z and [Mo(CO)2(S2C2Me 2)2]z (z = 0, 1−, 2−) by means of density functional theory. Spectroscopic, structural, and computational results make the ambiguities in descriptions of metal and ligand oxidation states in the series clear, revealing that traversal of the series in the reducing direction results in largely ligand-based reduction and that the ligand is an enedithiolate dianion in the terminal reduced members.; Chapter 3 describes the synthesis and structural characterization of synthetic analogues of the reduced sites of members of the DMSO reductase family of molybdoenzymes. A series of [Mo(QR′)(S 2C2R2)2]1− (Q = O, S, Se) represents the closest approaches thus far to the binding arrangements in the enzymes; dithiolene ligands simulate tight, symmetrical chelation by the pterindithiolene cofactor and the axial ligands R′Q − approximate serinate, cysteinate, or selenocysteinate binding. Monocarbonyl complexes [Mo(CO)(QR′)(S2C 2R2)2]1− (Q = S, Se), monooxo complexes [MoO(S2C2R2)2] 1−/2−, and the bridged dimers [Mo2(μ-Q)(S 2C2Me2)2]2− (Q = S, Se) and [Mo2(μ-SePh)(S2C2Ph 2)4]2− are also described.; As an extension of the chemistry in Chapter 3, the oxygen atom transfer reactions mediated by the synthetic analogues [MoIV(OR ′)(S2C2R2)2] 1− are discussed in Chapter 4. In systems with N-oxide and S-oxide substrates, the observed overall reaction sequence is [MoIV(OR′)(S2C2R 2)2]1− + XO → [MoVIO(OR ′)(S2C2R2)2] 1− → [MoVO(S2C2R 2)2]1−. Direct oxo transfer has been proven by isotope labeling. The MoVIO product in the first step is an intermediate in the overall reaction sequence, inasmuch as it is too unstable to isolate and decays to a MoVO product. This research affords the first analogue reaction systems of biological N-oxide and S-oxide substrates that are based on desoxo Mo(IV) complexes with biologically relevant coordination.; Chapter 5 reports the synthesis and structural characterization of the first synthetic analogues, mono(dithiolene) complexes [MoOCl(SAr)(bdt)] 1− and [MoO2(SAr)(bdt)]1, of th... |
