| Over the last decade, large-scale computer simulations based on quantum chemical methods have proven to be valuable tools for discovering mechanistic details of catalytic reactions and multi-electron redox processes. It is our view that a critical ingredient for the successful integration of theory and experiment lies in a balanced approach that embraces both evenhandedly. This integrated approach is applied to examine three very diverse fields: (i) irreversible, non-Nernstian redox processes ( ii) electrocatalytic CO2 reduction via a Ru- and Re-based polypyridyl catalysts and (iii) Cu-catalyzed cross-coupling reactions.;Cisplatin is one of the most successful anticancer drugs currently in use. Whereas its therapeutic value remains high, cisplatin displays several major problems, i.e. side effects and cancer cell resistance. One inspiring approach of improving cisplatin is to utilize Pt(IV) prodrugs that can be activated by a two-electron reduction once they are inside the cell. Unfortunately, the mechanism of the two-electron reduction process of these prodrugs has not been established. A series of electrochemical experiments coupled with calculations was employed to elucidate the structure of the Pt(III) intermediate and the mechanism for the irreversible, two-electron reduction process. In addition, a reliable estimate for the standard reduction potential E° was derived for the electrochemically irreversible Pt(IV) reduction, and was compared directly to the calculated reduction potentials. Finally, this valuable methodology still proved useful for a variety of other mechanistic applications.;The second problem of interest is related to the ever-increasing need for sources of energy. A critical technology needed for the production of fuel via artificial photosynthesis is the catalytic reduction of CO2 . A majority of work completed in the literature concentrates on the efficiency of their specific catalyst as opposed to its mechanism. By focusing on the mechanistic details with the aid of both computation and experimental techniques, we are no longer attempting to blindly design a catalyst for the reduction of CO2, but taking a more rational approach to catalyst improvement.;The final project focuses on judiciously designing organometallic ligand scaffolds for organic transformations, as opposed to catalyst optimization through a series of repetitive screening processes. Thus mapping a complete mechanism for the Cu-catalyzed Suzuki cross-coupling reaction of two C(sp 2) substrates is essential for discovering how to directly influence the rate-determining step. Only by understanding the structural motifs of the catalyst that manipulate the rate of the reaction can a more ideal ligand design be proposed and tested. |
