This award from the Chemical Structure, Dynamics and Mechanism Program of the Division of Chemistry supports Professor Dasan M. Thamattoor of the Chemistry Department at Colby College in Waterville, ME in his exploration of the following topics: 1) Generation of strained allene compounds via novel decomposition of spiropentanes; 2) Synthesis of derivatives of 1,2 cycloheptadiene and 1,2 cyclooctadiene that are stable enough to form crystals suitable for x-ray diffraction, and 3) Development of pyrolysis methods for converting cycloalkenylcarbenes to strained cyclic allenes. Computational studies using Density Functional Theory (DFT) would be done in parallel with the experiments to provide insight into product stabilities and reaction pathways. The proposed work, which integrates elements of synthetic, mechanistic, and computational organic chemistry, is designed to provide undergraduates with a wholesome research experience, and enable them to make original contributions to scientific knowledge.
Among the most important broader impacts of this research, as mentioned above, is the mentoring of undergraduate researchers and training them as future scientists in a predominantly undergraduate institution. A number of ideas for melding research and education, based on approaches that have already met with success, will be implemented. This is exemplified, for instance, by the incorporation of research-like projects and new pedagogical experiments in the introductory organic chemistry laboratory course. The proposal also seeks to continue Prof. Thamattoor's highly successful program that provides research opportunities to high school students over the summer months. Women, minorities, and students from disadvantaged backgrounds will also be recruited to participate in summer research activities. In addition, there will be new initiative that forges partnerships with elementary school teachers to specifically strengthen the science curriculum in the K-3 level. Finally, it is expected that a number of important fundamental chemical reaction pathways will be elucidated.
Many scientists have been fascinated by small-ring molecules incorporating the allenic subunit. Acyclic allenes have linear equilibrium geometries and the two orthogonally disposed, cumulated pi bonds ensure that the pair of substituents at the termini are also in planes that are perpendicular to each other. Of course, this preferred geometry can be only accommodated comfortably in larger ring systems (10-membered and up) but as the ring size decreases, the attendant distortions of the allenic group begin to inflict strain on the molecule. This work included several projects, appropriate for an undergraduate-oriented research program, that focused on the investigation of strained cyclic allenes. One goal was to develop an alternative method of generating these species based on the decomposition of specially designed spiropentanes. This new method complements existing methods and might even provide a route to hitherto inaccessible cyclic allenes. The second goal was to synthesize stable crystalline derivatives of 1,2-cycloheptadiene and 1,2-cyclooctadiene so that their solid state structures could be determined by single-crystal x-ray diffraction studies. This goal is significant as crystal structures of uncomplexed eight- and seven-membered carbocyclic allene derivatives are currently unavailable. This work has brought us closer to achieving the synthesis of the target allenes. The work integrated elements of synthetic, mechanistic, and computational organic chemistry, provided undergraduates with a wholesome research experience, and engaged them as partners in the scientific enterprise. The program, at the same time, also met important criteria of a quality science education in that it allowed students to learn useful experimental skills, think through problems, learn from mistakes, work collaboratively with others, and communicate effectively in written and oral formats. Over the life of this award a total of 21 Colby undergraduates, including four current students, have participated in research activities in our laboratory. In addition, 16 high school students were provided research internship opportunities over the past three summers. Women, minorities, and international students were all well represented among the participants. Successful partnerships were also forged with the teachers and special education staff to help teach children in the middle and elementary schools. Several publications and conference presentations featuring undergraduate student coauthors were derived from this award.
