Date of Award


Degree Type


Degree Name

Doctor of Philosophy


The initial step of photosynthesis involves transfer of an electron from a photo-excited porphyrin donor to a nearby ubiquinone acceptor. Compounds containing a porphyrin covalently linked to a benzoquinone have been shown to mimic this initial transfer and as such are useful models for the study of photo-induced intramolecular electron transfer. The first chapter of this thesis describes the synthesis of a linked porphyrin-benzoquinone species, designated P4Q. This compound consists of a tetra-aryl porphyrin linked cis-1,3 across a cyclobutane ring to a benzoquinone.;The photophysical properties of this compound and of two precursor species, the hydroquinone analog and the dimethoxy phenyl analog, designated as P4QH{dollar}\sb2{dollar} and P4DMB respectively, were measured in six solvents. The results indicate that intramolecular photo-induced electron transfer is possible in P4Q, and that relative to similar species it is surprisingly facile. The relatively fast observed rates for this electron transfer are rationalized in terms of the mediating role that the connecting linkage plays. The observed solvent effect on the rate of electron transfer was found to be consistent with Marcus theory.;The second and final chapter of this thesis outlines the attempted preparation of a water soluble porphyrin-cyclodextrin species and the attempts to determine complex dissociation constants for {dollar}\beta{dollar}-cyclodextrin-electron acceptor complexes in aqueous solution. This was an attempt to extend the use of {dollar}\beta{dollar}-cyclodextrin as a connecting linkage to aqueous solution. Cyclodextrins are useful as connecting linkages due to their ability to form inclusion complexes with a wide variety of species. This allows one porphyrin derivative, that linked to the cyclodextrin, to be used for screening several potential electron acceptors with a minimum of synthetic work. The attempts to measure the equilibrium dissociation constants were part of an attempt to quantify the kinetics of electron transfer in this system.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.