RUI: Reactive Intermediates and Unusual Molecules from Phenanthrene-based Precursors

With support from the Chemical Structure, Dynamics & Mechanism-B (CSDM-B) Program of the Chemistry Division and the Established Program to Stimulate Competitive Research (EPSCoR), Professor Dasan Thamattoor of the Department of Chemistry at Colby College and his team of undergraduate students are undertaking a study of reactive intermediates and unusual molecules generated from phenanthrene-based precursors. The structure and reactivity of the targeted chemical species, which are of academic as well as practical interest, will be investigated experimentally and by modern computational methods. In addition, several initiatives to create meaningful research experiences for undergraduates, foster international research collaborations with student participation, and promote high-quality science education for K-12 students in area schools will be pursued. Singlet vinylcarbenes play a key role in cyclopropene isomerizations and other important synthetic transformations. Yet little is known about their chemistry. Likewise, experimental data on the kinetics and structure of cyclopropylidene, the smallest carbocyclic carbene, and its derivatives, are quite sparse. In this proposal, cyclopropanated phenanthrene precursors will be used to investigate the structure and reactivities of vinylcarbenes and cyclopropylidenes. Furthermore, innovative approaches to using cyclobutanated phenanthrenes as sources of ketenes and allenes will be pursued. A broad range of experimental methods such as steady state photolysis, EPR spectroscopy, matrix isolation spectroscopy, and time-resolved laser flash photolysis as well as modern computational tools will be used in these investigations. The ready synthesis, stability, ease of handling, and versatility of the proposed precursors make these projects ideal for involving undergraduate students. The proposed work, which integrates synthetic, mechanistic, and computational organic chemistry, is designed to provide students with a comprehensive research experience, pique their curiosity, and engage them as partners in the discovery process. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.