Factors affecting the rate of electron transfer in mixed-valence biferrocenium cations

Electron transfer is a fundamental chemical process. It involves the movement of localized electronic charge from one atom, ion, or molecule to another. Despite its obvious fundamental nature, its practical importance, and several decades of active research, the factors which affect or control the electron transfer process are still not fully recognized or understood.The general environment surrounding the donor and acceptor sites of the electron transfer event consists of the intervening medium, which is the space most directly between the two sites, and what can be termed the 'global' environment, the balance of the space surrounding the sites of electron transfer. For intramolecular electron transfer in mixed-valence transition metal complexes, the donor and acceptor sites are typically the transition metal ions. The intervening environment usually consists of the ligand that bridges between the two metal centers; and the 'global' environment is highly variable. It can include non-bridging ligands, solvent molecules, counterions, other mixed valence molecules, zeolite cages, polymer matrices, interlamellar regions of clays, or even empty space.Much of the initial work concerning electron transfer between two well separated metal sites focused on the intervening media. Nevertheless, it seems reasonable that the 'global' environment may also play a significant role in determining the rate of electron transfer between two electron transfer sites.In this thesis, the dependence of intramolecular electron transfer on the 'global' environment is addressed. The molecular frameworks chosen are some mono-oxidized, mixed-valence biferrocenium systems shown below:$\sp*$Various forms of spectroscopy, with their inherent timescales, were used in conjunction with X-ray diffraction methods to determine the intramolecular electron transfer rates and characterize the 'global' environment.The effect on the rate of intramolecular electron transfer in the various cations with different anions is discussed. The nature of the 'global' environment is extremely important in influencing the electron transfer rate within the mixed-valence, biferrocenium cations. The position and dynamics of the anions found in the 'global' environment impact the intramolecular electron transfer rate greatly. ftn$\sp*$Please refer to the dissertation for diagrams.U of I OnlyETDs are only available to UIUC Users without author permissio