RUI: Enhancing Undergraduate Chemical Education Through Research: The Experimental and Theoretical Investigation of Unusual Carbenes

Colby College, Waterville ME

Investigators

Abstract

Carbene-like products obtained from nitrogen-containing precursors may in fact come from the excited state of the precursors themselves. In addition, many nitrogenous precursors can be hazardous to handle or may simply not be synthetically available to generate carbenes of interest - e.g., a convenient and widely applicable method of generating a-hydroxycarbenes is currently unavailable. This proposal describes an undergraduate-oriented research program designed to study unusual carbenes generated from various cyclopropanated aromatics instead of conventional sources such as diazo compounds and diazirines. These non-nitrogenous precursors provide a safe, viable, and alternative route to carbene generation. Specific projects include the investigation a-hydroxycarbenes and novel heterocyclopropylcarbenes (including oxiranyl- and aziridinyl carbenes) and the generation of a-ketocarbenes to address key mechanistic issues in Wolff rearrangement processes. Electron spin resonance spectroscopy, time-resolved laser flash photolysis, and advanced computational methods will be brought to bear on the investigations as well. With this Research at Undergraduate Institutions Award, the Organic and Macromolecular Chemistry Program supports the research of Professor Dasan M. Thamattoor, of the Department of Chemistry at Colby College. Professor Thamattoor and his students are exploring, via theory and wet chemistry, the preparation, structure, and reactivity of unusual electron-deficient species known as carbenes. These unusual species play central roles in a wide variety of chemical processes, and development of a detailed understanding of their structure and reaction chemistry will lead to the development of better predictive tools for the control of chemical reactivity. Whereas other routes to some of the targeted carbenes are known, Professor Thamattoor's studies address serious questions about the structure and reactivity of the carbenes generated via these other routes, and in addition offer promise for the generation of new, previously unavailable carbenes. Through a partnership with the Maine Research Internships for Teachers and Students (MERITS) program, Professor Thamattoor will enhance the educational experience provided by this research program by including high school teachers and students.