Applications of nucleophilic substitution and addition reactions of dicationic ruthenium and iridium arene complexes in organic synthesis and materials chemistry

The research in this dissertation is focused on the chemistry associated with dicationic ruthenium and iridium arene complexes. Most known examples of these complexes are stable in air and moisture which greatly facilitate their isolation, purification and handling. However, complexation with a dicationic metal center dramatically activates the arene rings and their substituents in these complexes towards reaction with nucleophiles, in some cases by several orders of magnitude, providing access potentially beneficial chemical transformations.; Therefore, taking advantage of these enhanced reactivity allowed us to develop a new synthetic methodology for the synthesis of spirocyclic compounds, organic compounds composed of two or more rings joined by a single atom. This method relies on intramolecular nucleophilic addition reactions at the dicationic arene complexes to construct the spirocyclic framework and takes advantage of the substantial activation of the arene ligands in these complexes toward nucleophilic attack. Employing the more activated dicationic ruthenium and iridium arene complexes has allowed for the use of a wide range of nucleophilies in the intramolecular nucleophilic addition reactions, which could ultimately lead to the synthesis of several important types of spirocyclic ring systems. We also extensively investigated nucleophilic substitution reactions of mono and dihalogenated dicationic arene complexes. In the course of this work, we have successfully synthesized several dicationic arene complexes that exhibit exceptionally weak metal-arene bonds; we have investigated the arene displacement and arene exchange reactions of these complexes.