Electronic Structure of Metal Ion-Dioxygen Complexes

Citation

Miskowski, Vincent Mark (1973) Electronic Structure of Metal Ion-Dioxygen Complexes. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ZFYP-9D77. https://resolver.caltech.edu/CaltechTHESIS:02022018-101456398

Abstract

The electronic structures of cobalt complexes containing O₂ units as ligands have been investigated, primarily by electronic spectroscopy. Various cobalt complexes containing, the structural units present in the O₂ complexes were investigated, and a systematic and self-consistent classification of their ligand field electronic transitions, charge-transfer electronic transitions, and excited state reactivities developed, which provided a basis for understanding the O₂ complexes.

The O₂ complexes investigated were all found to contain low-spin d⁶ cobalt (III) central metal ions, by spectroscopic criteria, and either peroxide or superoxide ligands. The O₂^n- ligands have positions in the spectrochemical series between those of ammonia and water, and have characteristic charge-transfer transitions in their complexes, superoxide complexes showing low energy metal-to-ligand transitions, while both superoxide and peroxide complexes show characteristic ligand-to-metal transitions in the UV. Extensive comparisons were made to O₂ complexes of other metal ions, and the binding of dioxygen to metal ions concluded to be oxidative addition in general. Autoxidation of metal ions and the structures and properties of oxymetalloproteins have been considered in the light of these results, and the formulation of addition of O₂ to Cu(I) and Fe(II) as one- and two-electron oxidative addition, respectively, is discussed.

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