High Energy Routes to Strained Molecules and Reactive Intermediates

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In this project funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Richard Johnson and his students at the University of New Hampshire Department of Chemistry will investigate the chemistry of highly energetic intermediates, which are generated either by protonation in superacids, hydrogen atom addition, thermolysis or electron transfer. One important goal is to explore the cationic and free-radical isomerization of polycyclic aromatic hydrocarbons. These are substances of broad importance across science - from interstellar chemistry to materials for molecular electronics. This project includes a high level of synergy between theory and experiment. The proposed research represents an intellectually rich and diverse series of computational and experimental experiences, which will serve as effective training for graduate and undergraduate students at the University of New Hampshire, including women and minorities. Outreach activities will focus on the development of new undergraduate laboratory experiments which are based on NSF-funded research across the field of chemistry. The proposed research continues previous NSF-funded studies. The major focus will be on rearrangements, cyclizations and coupling reactions of aromatic compounds. Proposed superacid-catalyzed chemistry will utilize a microwave reactor to extend the range of cationic chemistry to include new higher energy processes. Building on recent group discoveries, which include both superacid and free-radical catalyzed skeletal isomerizations of polycyclic aromatic hydrocarbons, the principal investigator and his students will combine theory and experiment to seek mechanistic understanding of these reactions. One important goal is to demonstrate that hydrogen atoms are universal catalysts in high temperature chemistry, just as the proton catalyzes reactions in solution. A second major emphasis will be on methodology development and new applications of the electron transfer model for polar bimolecular reactions which was developed at the University of New Hampshire. This model treats all polar bimolecular reactions as single electron transfer processes, using spin density maps to successfully predict regiochemistry and stereochemistry in a broad array of chemical reactions.